jdk/src/share/classes/javax/swing/GroupLayout.java
changeset 2 90ce3da70b43
child 1301 15e81207e1f2
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/jdk/src/share/classes/javax/swing/GroupLayout.java	Sat Dec 01 00:00:00 2007 +0000
@@ -0,0 +1,3741 @@
+/*
+ * Copyright 2006 Sun Microsystems, Inc.  All Rights Reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.  Sun designates this
+ * particular file as subject to the "Classpath" exception as provided
+ * by Sun in the LICENSE file that accompanied this code.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ */
+package javax.swing;
+
+import java.awt.Component;
+import java.awt.Container;
+import java.awt.Dimension;
+import java.awt.Insets;
+import java.awt.LayoutManager2;
+import java.util.*;
+import static java.awt.Component.BaselineResizeBehavior;
+import static javax.swing.LayoutStyle.ComponentPlacement;
+import static javax.swing.SwingConstants.HORIZONTAL;
+import static javax.swing.SwingConstants.VERTICAL;
+
+/**
+ * {@code GroupLayout} is a {@code LayoutManager} that hierarchically
+ * groups components in order to position them in a {@code Container}.
+ * {@code GroupLayout} is intended for use by builders, but may be
+ * hand-coded as well.
+ * Grouping is done by instances of the {@link Group Group} class. {@code
+ * GroupLayout} supports two types of groups. A sequential group
+ * positions its child elements sequentially, one after another. A
+ * parallel group aligns its child elements in one of four ways.
+ * <p>
+ * Each group may contain any number of elements, where an element is
+ * a {@code Group}, {@code Component}, or gap. A gap can be thought
+ * of as an invisible component with a minimum, preferred and maximum
+ * size. In addition {@code GroupLayout} supports a preferred gap,
+ * whose value comes from {@code LayoutStyle}.
+ * <p>
+ * Elements are similar to a spring. Each element has a range as
+ * specified by a minimum, preferred and maximum.  Gaps have either a
+ * developer-specified range, or a range determined by {@code
+ * LayoutStyle}. The range for {@code Component}s is determined from
+ * the {@code Component}'s {@code getMinimumSize}, {@code
+ * getPreferredSize} and {@code getMaximumSize} methods. In addition,
+ * when adding {@code Component}s you may specify a particular range
+ * to use instead of that from the component. The range for a {@code
+ * Group} is determined by the type of group. A {@code ParallelGroup}'s
+ * range is the maximum of the ranges of its elements. A {@code
+ * SequentialGroup}'s range is the sum of the ranges of its elements.
+ * <p>
+ * {@code GroupLayout} treats each axis independently.  That is, there
+ * is a group representing the horizontal axis, and a group
+ * representing the vertical axis.  The horizontal group is
+ * responsible for determining the minimum, preferred and maximum size
+ * along the horizontal axis as well as setting the x and width of the
+ * components contained in it. The vertical group is responsible for
+ * determining the minimum, preferred and maximum size along the
+ * vertical axis as well as setting the y and height of the
+ * components contained in it. Each {@code Component} must exist in both
+ * a horizontal and vertical group, otherwise an {@code IllegalStateException}
+ * is thrown during layout, or when the minimum, preferred or
+ * maximum size is requested.
+ * <p>
+ * The following diagram shows a sequential group along the horizontal
+ * axis. The sequential group contains three components. A parallel group
+ * was used along the vertical axis.
+ * <p align="center">
+ * <img src="doc-files/groupLayout.1.gif">
+ * <p>
+ * To reinforce that each axis is treated independently the diagram shows
+ * the range of each group and element along each axis. The
+ * range of each component has been projected onto the axes,
+ * and the groups are rendered in blue (horizontal) and red (vertical).
+ * For readability there is a gap between each of the elements in the
+ * sequential group.
+ * <p>
+ * The sequential group along the horizontal axis is rendered as a solid
+ * blue line. Notice the sequential group is the sum of the children elements
+ * it contains.
+ * <p>
+ * Along the vertical axis the parallel group is the maximum of the height
+ * of each of the components. As all three components have the same height,
+ * the parallel group has the same height.
+ * <p>
+ * The following diagram shows the same three components, but with the
+ * parallel group along the horizontal axis and the sequential group along
+ * the vertical axis.
+ * <p>
+ * <p align="center">
+ * <img src="doc-files/groupLayout.2.gif">
+ * <p>
+ * As {@code c1} is the largest of the three components, the parallel
+ * group is sized to {@code c1}. As {@code c2} and {@code c3} are smaller
+ * than {@code c1} they are aligned based on the alignment specified
+ * for the component (if specified) or the default alignment of the
+ * parallel group. In the diagram {@code c2} and {@code c3} were created
+ * with an alignment of {@code LEADING}. If the component orientation were
+ * right-to-left then {@code c2} and {@code c3} would be positioned on
+ * the opposite side.
+ * <p>
+ * The following diagram shows a sequential group along both the horizontal
+ * and vertical axis.
+ * <p align="center">
+ * <img src="doc-files/groupLayout.3.gif">
+ * <p>
+ * {@code GroupLayout} provides the ability to insert gaps between
+ * {@code Component}s. The size of the gap is determined by an
+ * instance of {@code LayoutStyle}. This may be turned on using the
+ * {@code setAutoCreateGaps} method.  Similarly, you may use
+ * the {@code setAutoCreateContainerGaps} method to insert gaps
+ * between components that touch the edge of the parent container and the
+ * container.
+ * <p>
+ * The following builds a panel consisting of two labels in
+ * one column, followed by two textfields in the next column:
+ * <pre>
+ *   JComponent panel = ...;
+ *   GroupLayout layout = new GroupLayout(panel);
+ *   panel.setLayout(layout);
+ *
+ *   // Turn on automatically adding gaps between components
+ *   layout.setAutoCreateGaps(true);
+ *
+ *   // Turn on automatically creating gaps between components that touch
+ *   // the edge of the container and the container.
+ *   layout.setAutoCreateContainerGaps(true);
+ *
+ *   // Create a sequential group for the horizontal axis.
+ *
+ *   GroupLayout.SequentialGroup hGroup = layout.createSequentialGroup();
+ *
+ *   // The sequential group in turn contains two parallel groups.
+ *   // One parallel group contains the labels, the other the text fields.
+ *   // Putting the labels in a parallel group along the horizontal axis
+ *   // positions them at the same x location.
+ *   //
+ *   // Variable indentation is used to reinforce the level of grouping.
+ *   hGroup.addGroup(layout.createParallelGroup().
+ *            addComponent(label1).addComponent(label2));
+ *   hGroup.addGroup(layout.createParallelGroup().
+ *            addComponent(tf1).addComponent(tf2));
+ *   layout.setHorizontalGroup(hGroup);
+ *
+ *   // Create a sequential group for the vertical axis.
+ *   GroupLayout.SequentialGroup vGroup = layout.createSequentialGroup();
+ *
+ *   // The sequential group contains two parallel groups that align
+ *   // the contents along the baseline. The first parallel group contains
+ *   // the first label and text field, and the second parallel group contains
+ *   // the second label and text field. By using a sequential group
+ *   // the labels and text fields are positioned vertically after one another.
+ *   vGroup.addGroup(layout.createParallelGroup(Alignment.BASELINE).
+ *            addComponent(label1).addComponent(tf1));
+ *   vGroup.addGroup(layout.createParallelGroup(Alignment.BASELINE).
+ *            addComponent(label2).addComponent(tf2));
+ *   layout.setVerticalGroup(vGroup);
+ * </pre>
+ * <p>
+ * When run the following is produced.
+ * <p align="center">
+ * <img src="doc-files/groupLayout.example.png">
+ * <p>
+ * This layout consists of the following.
+ * <ul><li>The horizontal axis consists of a sequential group containing two
+ *         parallel groups.  The first parallel group contains the labels,
+ *         and the second parallel group contains the text fields.
+ *     <li>The vertical axis consists of a sequential group
+ *         containing two parallel groups.  The parallel groups are configured
+ *         to align their components along the baseline. The first parallel
+ *         group contains the first label and first text field, and
+ *         the second group consists of the second label and second
+ *         text field.
+ * </ul>
+ * There are a couple of things to notice in this code:
+ * <ul>
+ *   <li>You need not explicitly add the components to the container; this
+ *       is indirectly done by using one of the {@code add} methods of
+ *       {@code Group}.
+ *   <li>The various {@code add} methods return
+ *       the caller.  This allows for easy chaining of invocations.  For
+ *       example, {@code group.addComponent(label1).addComponent(label2);} is
+ *       equivalent to
+ *       {@code group.addComponent(label1); group.addComponent(label2);}.
+ *   <li>There are no public constructors for {@code Group}s; instead
+ *       use the create methods of {@code GroupLayout}.
+ * </ul>
+ *
+ * @author Tomas Pavek
+ * @author Jan Stola
+ * @author Scott Violet
+ * @since 1.6
+ */
+public class GroupLayout implements LayoutManager2 {
+    // Used in size calculations
+    private static final int MIN_SIZE = 0;
+
+    private static final int PREF_SIZE = 1;
+
+    private static final int MAX_SIZE = 2;
+
+    // Used by prepare, indicates min, pref or max isn't going to be used.
+    private static final int SPECIFIC_SIZE = 3;
+
+    private static final int UNSET = Integer.MIN_VALUE;
+
+    /**
+     * Indicates the size from the component or gap should be used for a
+     * particular range value.
+     *
+     * @see Group
+     */
+    public static final int DEFAULT_SIZE = -1;
+
+    /**
+     * Indicates the preferred size from the component or gap should
+     * be used for a particular range value.
+     *
+     * @see Group
+     */
+    public static final int PREFERRED_SIZE = -2;
+
+    // Whether or not we automatically try and create the preferred
+    // padding between components.
+    private boolean autocreatePadding;
+
+    // Whether or not we automatically try and create the preferred
+    // padding between components the touch the edge of the container and
+    // the container.
+    private boolean autocreateContainerPadding;
+
+    /**
+     * Group responsible for layout along the horizontal axis.  This is NOT
+     * the user specified group, use getHorizontalGroup to dig that out.
+     */
+    private Group horizontalGroup;
+
+    /**
+     * Group responsible for layout along the vertical axis.  This is NOT
+     * the user specified group, use getVerticalGroup to dig that out.
+     */
+    private Group verticalGroup;
+
+    // Maps from Component to ComponentInfo.  This is used for tracking
+    // information specific to a Component.
+    private Map<Component,ComponentInfo> componentInfos;
+
+    // Container we're doing layout for.
+    private Container host;
+
+    // Used by areParallelSiblings, cached to avoid excessive garbage.
+    private Set<Spring> tmpParallelSet;
+
+    // Indicates Springs have changed in some way since last change.
+    private boolean springsChanged;
+
+    // Indicates invalidateLayout has been invoked.
+    private boolean isValid;
+
+    // Whether or not any preferred padding (or container padding) springs
+    // exist
+    private boolean hasPreferredPaddingSprings;
+
+    /**
+     * The LayoutStyle instance to use, if null the sharedInstance is used.
+     */
+    private LayoutStyle layoutStyle;
+
+    /**
+     * If true, components that are not visible are treated as though they
+     * aren't there.
+     */
+    private boolean honorsVisibility;
+
+
+    /**
+     * Enumeration of the possible ways {@code ParallelGroup} can align
+     * its children.
+     *
+     * @see #createParallelGroup(Alignment)
+     * @since 1.6
+     */
+    public enum Alignment {
+        /**
+         * Indicates the elements should be
+         * aligned to the origin.  For the horizontal axis with a left to
+         * right orientation this means aligned to the left edge. For the
+         * vertical axis leading means aligned to the top edge.
+         *
+         * @see #createParallelGroup(Alignment)
+         */
+        LEADING,
+
+        /**
+         * Indicates the elements should be aligned to the end of the
+         * region.  For the horizontal axis with a left to right
+         * orientation this means aligned to the right edge. For the
+         * vertical axis trailing means aligned to the bottom edge.
+         *
+         * @see #createParallelGroup(Alignment)
+         */
+        TRAILING,
+
+        /**
+         * Indicates the elements should be centered in
+         * the region.
+         *
+         * @see #createParallelGroup(Alignment)
+         */
+        CENTER,
+
+        /**
+         * Indicates the elements should be aligned along
+         * their baseline.
+         *
+         * @see #createParallelGroup(Alignment)
+         * @see #createBaselineGroup(boolean,boolean)
+         */
+        BASELINE
+    }
+
+
+    private static void checkSize(int min, int pref, int max,
+            boolean isComponentSpring) {
+        checkResizeType(min, isComponentSpring);
+        if (!isComponentSpring && pref < 0) {
+            throw new IllegalArgumentException("Pref must be >= 0");
+        } else if (isComponentSpring) {
+            checkResizeType(pref, true);
+        }
+        checkResizeType(max, isComponentSpring);
+        checkLessThan(min, pref);
+        checkLessThan(pref, max);
+    }
+
+    private static void checkResizeType(int type, boolean isComponentSpring) {
+        if (type < 0 && ((isComponentSpring && type != DEFAULT_SIZE &&
+                type != PREFERRED_SIZE) ||
+                (!isComponentSpring && type != PREFERRED_SIZE))) {
+            throw new IllegalArgumentException("Invalid size");
+        }
+    }
+
+    private static void checkLessThan(int min, int max) {
+        if (min >= 0 && max >= 0 && min > max) {
+            throw new IllegalArgumentException(
+                    "Following is not met: min<=pref<=max");
+        }
+    }
+
+    /**
+     * Creates a {@code GroupLayout} for the specified {@code Container}.
+     *
+     * @param host the {@code Container} the {@code GroupLayout} is
+     *        the {@code LayoutManager} for
+     * @throws IllegalArgumentException if host is {@code null}
+     */
+    public GroupLayout(Container host) {
+        if (host == null) {
+            throw new IllegalArgumentException("Container must be non-null");
+        }
+        honorsVisibility = true;
+        this.host = host;
+        setHorizontalGroup(createParallelGroup(Alignment.LEADING, true));
+        setVerticalGroup(createParallelGroup(Alignment.LEADING, true));
+        componentInfos = new HashMap<Component,ComponentInfo>();
+        tmpParallelSet = new HashSet<Spring>();
+    }
+
+    /**
+     * Sets whether component visiblity is considered when sizing and
+     * positioning components. A value of {@code true} indicates that
+     * non-visible components should not be treated as part of the
+     * layout. A value of {@code false} indicates that components should be
+     * positioned and sized regardless of visibility.
+     * <p>
+     * A value of {@code false} is useful when the visibility of components
+     * is dynamically adjusted and you don't want surrounding components and
+     * the sizing to change.
+     * <p>
+     * The specified value is used for components that do not have an
+     * explicit visibility specified.
+     * <p>
+     * The default is {@code true}.
+     *
+     * @param honorsVisibility whether component visiblity is considered when
+     *                         sizing and positioning components
+     * @see #setHonorsVisibility(Component,Boolean)
+     */
+    public void setHonorsVisibility(boolean honorsVisibility) {
+        if (this.honorsVisibility != honorsVisibility) {
+            this.honorsVisibility = honorsVisibility;
+            springsChanged = true;
+            isValid = false;
+            invalidateHost();
+        }
+    }
+
+    /**
+     * Returns whether component visiblity is considered when sizing and
+     * positioning components.
+     *
+     * @return whether component visiblity is considered when sizing and
+     *         positioning components
+     */
+    public boolean getHonorsVisibility() {
+        return honorsVisibility;
+    }
+
+    /**
+     * Sets whether the component's visiblity is considered for
+     * sizing and positioning. A value of {@code Boolean.TRUE}
+     * indicates that if {@code component} is not visible it should
+     * not be treated as part of the layout. A value of {@code false}
+     * indicates that {@code component} is positioned and sized
+     * regardless of it's visibility.  A value of {@code null}
+     * indicates the value specified by the single argument method {@code
+     * setHonorsVisibility} should be used.
+     * <p>
+     * If {@code component} is not a child of the {@code Container} this
+     * {@code GroupLayout} is managine, it will be added to the
+     * {@code Container}.
+     *
+     * @param component the component
+     * @param honorsVisibility whether {@code component}'s visiblity should be
+     *              considered for sizing and positioning
+     * @throws IllegalArgumentException if {@code component} is {@code null}
+     * @see #setHonorsVisibility(Component,Boolean)
+     */
+    public void setHonorsVisibility(Component component,
+            Boolean honorsVisibility) {
+        if (component == null) {
+            throw new IllegalArgumentException("Component must be non-null");
+        }
+        getComponentInfo(component).setHonorsVisibility(honorsVisibility);
+        springsChanged = true;
+        isValid = false;
+        invalidateHost();
+    }
+
+    /**
+     * Sets whether a gap between components should automatically be
+     * created.  For example, if this is {@code true} and you add two
+     * components to a {@code SequentialGroup} a gap between the
+     * two components is automatically be created.  The default is
+     * {@code false}.
+     *
+     * @param autoCreatePadding whether a gap between components is
+     *        automatically created
+     */
+    public void setAutoCreateGaps(boolean autoCreatePadding) {
+        if (this.autocreatePadding != autoCreatePadding) {
+            this.autocreatePadding = autoCreatePadding;
+            invalidateHost();
+        }
+    }
+
+    /**
+     * Returns {@code true} if gaps between components are automatically
+     * created.
+     *
+     * @return {@code true} if gaps between components are automatically
+     *         created
+     */
+    public boolean getAutoCreateGaps() {
+        return autocreatePadding;
+    }
+
+    /**
+     * Sets whether a gap between the container and components that
+     * touch the border of the container should automatically be
+     * created. The default is {@code false}.
+     *
+     * @param autoCreateContainerPadding whether a gap between the container and
+     *        components that touch the border of the container should
+     *        automatically be created
+     */
+    public void setAutoCreateContainerGaps(boolean autoCreateContainerPadding){
+        if (this.autocreateContainerPadding != autoCreateContainerPadding) {
+            this.autocreateContainerPadding = autoCreateContainerPadding;
+            horizontalGroup = createTopLevelGroup(getHorizontalGroup());
+            verticalGroup = createTopLevelGroup(getVerticalGroup());
+            invalidateHost();
+        }
+    }
+
+    /**
+     * Returns {@code true} if gaps between the container and components that
+     * border the container are automatically created.
+     *
+     * @return {@code true} if gaps between the container and components that
+     *         border the container are automatically created
+     */
+    public boolean getAutoCreateContainerGaps() {
+        return autocreateContainerPadding;
+    }
+
+    /**
+     * Sets the {@code Group} that positions and sizes
+     * components along the horizontal axis.
+     *
+     * @param group the {@code Group} that positions and sizes
+     *        components along the horizontal axis
+     * @throws IllegalArgumentException if group is {@code null}
+     */
+    public void setHorizontalGroup(Group group) {
+        if (group == null) {
+            throw new IllegalArgumentException("Group must be non-null");
+        }
+        horizontalGroup = createTopLevelGroup(group);
+        invalidateHost();
+    }
+
+    /**
+     * Returns the {@code Group} that positions and sizes components
+     * along the horizontal axis.
+     *
+     * @return the {@code Group} responsible for positioning and
+     *         sizing component along the horizontal axis
+     */
+    private Group getHorizontalGroup() {
+        int index = 0;
+        if (horizontalGroup.springs.size() > 1) {
+            index = 1;
+        }
+        return (Group)horizontalGroup.springs.get(index);
+    }
+
+    /**
+     * Sets the {@code Group} that positions and sizes
+     * components along the vertical axis.
+     *
+     * @param group the {@code Group} that positions and sizes
+     *        components along the vertical axis
+     * @throws IllegalArgumentException if group is {@code null}
+     */
+    public void setVerticalGroup(Group group) {
+        if (group == null) {
+            throw new IllegalArgumentException("Group must be non-null");
+        }
+        verticalGroup = createTopLevelGroup(group);
+        invalidateHost();
+    }
+
+    /**
+     * Returns the {@code Group} that positions and sizes components
+     * along the vertical axis.
+     *
+     * @return the {@code Group} responsible for positioning and
+     *         sizing component along the vertical axis
+     */
+    private Group getVerticalGroup() {
+        int index = 0;
+        if (verticalGroup.springs.size() > 1) {
+            index = 1;
+        }
+        return (Group)verticalGroup.springs.get(index);
+    }
+
+    /**
+     * Wraps the user specified group in a sequential group.  If
+     * container gaps should be generated the necessary springs are
+     * added.
+     */
+    private Group createTopLevelGroup(Group specifiedGroup) {
+        SequentialGroup group = createSequentialGroup();
+        if (getAutoCreateContainerGaps()) {
+            group.addSpring(new ContainerAutoPreferredGapSpring());
+            group.addGroup(specifiedGroup);
+            group.addSpring(new ContainerAutoPreferredGapSpring());
+        } else {
+            group.addGroup(specifiedGroup);
+        }
+        return group;
+    }
+
+    /**
+     * Creates and returns a {@code SequentialGroup}.
+     *
+     * @return a new {@code SequentialGroup}
+     */
+    public SequentialGroup createSequentialGroup() {
+        return new SequentialGroup();
+    }
+
+    /**
+     * Creates and returns a {@code ParallelGroup} with an alignment of
+     * {@code Alignment.LEADING}.  This is a cover method for the more
+     * general {@code createParallelGroup(Alignment)} method.
+     *
+     * @return a new {@code ParallelGroup}
+     * @see #createParallelGroup(Alignment)
+     */
+    public ParallelGroup createParallelGroup() {
+        return createParallelGroup(Alignment.LEADING);
+    }
+
+    /**
+     * Creates and returns a {@code ParallelGroup} with the specified
+     * alignment.  This is a cover method for the more general {@code
+     * createParallelGroup(Alignment,boolean)} method with {@code true}
+     * supplied for the second argument.
+     *
+     * @param alignment the alignment for the elements of the group
+     * @throws IllegalArgumentException if {@code alignment} is {@code null}
+     * @return a new {@code ParallelGroup}
+     * @see #createBaselineGroup
+     * @see ParallelGroup
+     */
+    public ParallelGroup createParallelGroup(Alignment alignment) {
+        return createParallelGroup(alignment, true);
+    }
+
+    /**
+     * Creates and returns a {@code ParallelGroup} with the specified
+     * alignment and resize behavior. The {@code
+     * alignment} argument specifies how children elements are
+     * positioned that do not fill the group. For example, if a {@code
+     * ParallelGroup} with an alignment of {@code TRAILING} is given
+     * 100 and a child only needs 50, the child is
+     * positioned at the position 50 (with a component orientation of
+     * left-to-right).
+     * <p>
+     * Baseline alignment is only useful when used along the vertical
+     * axis. A {@code ParallelGroup} created with a baseline alignment
+     * along the horizontal axis is treated as {@code LEADING}.
+     * <p>
+     * Refer to {@link GroupLayout.ParallelGroup ParallelGroup} for details on
+     * the behavior of baseline groups.
+     *
+     * @param alignment the alignment for the elements of the group
+     * @param resizable {@code true} if the group is resizable; if the group
+     *        is not resizable the preferred size is used for the
+     *        minimum and maximum size of the group
+     * @throws IllegalArgumentException if {@code alignment} is {@code null}
+     * @return a new {@code ParallelGroup}
+     * @see #createBaselineGroup
+     * @see GroupLayout.ParallelGroup
+     */
+    public ParallelGroup createParallelGroup(Alignment alignment,
+            boolean resizable){
+        if (alignment == Alignment.BASELINE) {
+            return new BaselineGroup(resizable);
+        }
+        return new ParallelGroup(alignment, resizable);
+    }
+
+    /**
+     * Creates and returns a {@code ParallelGroup} that aligns it's
+     * elements along the baseline.
+     *
+     * @param resizable whether the group is resizable
+     * @param anchorBaselineToTop whether the baseline is anchored to
+     *        the top or bottom of the group
+     * @see #createBaselineGroup
+     * @see ParallelGroup
+     */
+    public ParallelGroup createBaselineGroup(boolean resizable,
+            boolean anchorBaselineToTop) {
+        return new BaselineGroup(resizable, anchorBaselineToTop);
+    }
+
+    /**
+     * Forces the specified components to have the same size
+     * regardless of their preferred, minimum or maximum sizes. Components that
+     * are linked are given the maximum of the preferred size of each of
+     * the linked components. For example, if you link two components with
+     * a preferred width of 10 and 20, both components are given a width of 20.
+     * <p>
+     * This can be used multiple times to force any number of
+     * components to share the same size.
+     * <p>
+     * Linked Components are not be resizable.
+     *
+     * @param components the {@code Component}s that are to have the same size
+     * @throws IllegalArgumentException if {@code components} is
+     *         {@code null}, or contains {@code null}
+     * @see #linkSize(int,Component[])
+     */
+    public void linkSize(Component... components) {
+        linkSize(SwingConstants.HORIZONTAL, components);
+        linkSize(SwingConstants.VERTICAL, components);
+    }
+
+    /**
+     * Forces the specified components to have the same size along the
+     * specified axis regardless of their preferred, minimum or
+     * maximum sizes. Components that are linked are given the maximum
+     * of the preferred size of each of the linked components. For
+     * example, if you link two components along the horizontal axis
+     * and the preferred width is 10 and 20, both components are given
+     * a width of 20.
+     * <p>
+     * This can be used multiple times to force any number of
+     * components to share the same size.
+     * <p>
+     * Linked {@code Component}s are not be resizable.
+     *
+     * @param components the {@code Component}s that are to have the same size
+     * @param axis the axis to link the size along; one of
+     *             {@code SwingConstants.HORIZONTAL} or
+     *             {@code SwingConstans.VERTICAL}
+     * @throws IllegalArgumentException if {@code components} is
+     *         {@code null}, or contains {@code null}; or {@code axis}
+     *          is not {@code SwingConstants.HORIZONTAL} or
+     *          {@code SwingConstants.VERTICAL}
+     */
+    public void linkSize(int axis, Component... components) {
+        if (components == null) {
+            throw new IllegalArgumentException("Components must be non-null");
+        }
+        for (int counter = components.length - 1; counter >= 0; counter--) {
+            Component c = components[counter];
+            if (components[counter] == null) {
+                throw new IllegalArgumentException(
+                        "Components must be non-null");
+            }
+            // Force the component to be added
+            getComponentInfo(c);
+        }
+        int glAxis;
+        if (axis == SwingConstants.HORIZONTAL) {
+            glAxis = HORIZONTAL;
+        } else if (axis == SwingConstants.VERTICAL) {
+            glAxis = VERTICAL;
+        } else {
+            throw new IllegalArgumentException("Axis must be one of " +
+                    "SwingConstants.HORIZONTAL or SwingConstants.VERTICAL");
+        }
+        LinkInfo master = getComponentInfo(
+                components[components.length - 1]).getLinkInfo(glAxis);
+        for (int counter = components.length - 2; counter >= 0; counter--) {
+            master.add(getComponentInfo(components[counter]));
+        }
+        invalidateHost();
+    }
+
+    /**
+     * Replaces an existing component with a new one.
+     *
+     * @param existingComponent the component that should be removed
+     *        and replaced with {@code newComponent}
+     * @param newComponent the component to put in
+     *        {@code existingComponent}'s place
+     * @throws IllegalArgumentException if either of the components are
+     *         {@code null} or {@code existingComponent} is not being managed
+     *         by this layout manager
+     */
+    public void replace(Component existingComponent, Component newComponent) {
+        if (existingComponent == null || newComponent == null) {
+            throw new IllegalArgumentException("Components must be non-null");
+        }
+        // Make sure all the components have been registered, otherwise we may
+        // not update the correct Springs.
+        if (springsChanged) {
+            registerComponents(horizontalGroup, HORIZONTAL);
+            registerComponents(verticalGroup, VERTICAL);
+        }
+        ComponentInfo info = componentInfos.remove(existingComponent);
+        if (info == null) {
+            throw new IllegalArgumentException("Component must already exist");
+        }
+        host.remove(existingComponent);
+        if (newComponent.getParent() != host) {
+            host.add(newComponent);
+        }
+        info.setComponent(newComponent);
+        componentInfos.put(newComponent, info);
+        invalidateHost();
+    }
+
+    /**
+     * Sets the {@code LayoutStyle} used to calculate the preferred
+     * gaps between components. A value of {@code null} indicates the
+     * shared instance of {@code LayoutStyle} should be used.
+     *
+     * @param layoutStyle the {@code LayoutStyle} to use
+     * @see LayoutStyle
+     */
+    public void setLayoutStyle(LayoutStyle layoutStyle) {
+        this.layoutStyle = layoutStyle;
+        invalidateHost();
+    }
+
+    /**
+     * Returns the {@code LayoutStyle} used for calculating the preferred
+     * gap between components. This returns the value specified to
+     * {@code setLayoutStyle}, which may be {@code null}.
+     *
+     * @return the {@code LayoutStyle} used for calculating the preferred
+     *         gap between components
+     */
+    public LayoutStyle getLayoutStyle() {
+        return layoutStyle;
+    }
+
+    private LayoutStyle getLayoutStyle0() {
+        LayoutStyle layoutStyle = getLayoutStyle();
+        if (layoutStyle == null) {
+            layoutStyle = LayoutStyle.getInstance();
+        }
+        return layoutStyle;
+    }
+
+    private void invalidateHost() {
+        if (host instanceof JComponent) {
+            ((JComponent)host).revalidate();
+        } else {
+            host.invalidate();
+        }
+        host.repaint();
+    }
+
+    //
+    // LayoutManager
+    //
+    /**
+     * Notification that a {@code Component} has been added to
+     * the parent container.  You should not invoke this method
+     * directly, instead you should use one of the {@code Group}
+     * methods to add a {@code Component}.
+     *
+     * @param name the string to be associated with the component
+     * @param component the {@code Component} to be added
+     */
+    public void addLayoutComponent(String name, Component component) {
+    }
+
+    /**
+     * Notification that a {@code Component} has been removed from
+     * the parent container.  You should not invoke this method
+     * directly, instead invoke {@code remove} on the parent
+     * {@code Container}.
+     *
+     * @param component the component to be removed
+     * @see java.awt.Component#remove
+     */
+    public void removeLayoutComponent(Component component) {
+        ComponentInfo info = componentInfos.remove(component);
+        if (info != null) {
+            info.dispose();
+            springsChanged = true;
+            isValid = false;
+        }
+    }
+
+    /**
+     * Returns the preferred size for the specified container.
+     *
+     * @param parent the container to return the preferred size for
+     * @return the preferred size for {@code parent}
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} this was created with
+     * @throws IllegalStateException if any of the components added to
+     *         this layout are not in both a horizontal and vertical group
+     * @see java.awt.Container#getPreferredSize
+     */
+    public Dimension preferredLayoutSize(Container parent) {
+        checkParent(parent);
+        prepare(PREF_SIZE);
+        return adjustSize(horizontalGroup.getPreferredSize(HORIZONTAL),
+                verticalGroup.getPreferredSize(VERTICAL));
+    }
+
+    /**
+     * Returns the minimum size for the specified container.
+     *
+     * @param parent the container to return the size for
+     * @return the minimum size for {@code parent}
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} that this was created with
+     * @throws IllegalStateException if any of the components added to
+     *         this layout are not in both a horizontal and vertical group
+     * @see java.awt.Container#getMinimumSize
+     */
+    public Dimension minimumLayoutSize(Container parent) {
+        checkParent(parent);
+        prepare(MIN_SIZE);
+        return adjustSize(horizontalGroup.getMinimumSize(HORIZONTAL),
+                verticalGroup.getMinimumSize(VERTICAL));
+    }
+
+    /**
+     * Lays out the specified container.
+     *
+     * @param parent the container to be laid out
+     * @throws IllegalStateException if any of the components added to
+     *         this layout are not in both a horizontal and vertical group
+     */
+    public void layoutContainer(Container parent) {
+        // Step 1: Prepare for layout.
+        prepare(SPECIFIC_SIZE);
+        Insets insets = parent.getInsets();
+        int width = parent.getWidth() - insets.left - insets.right;
+        int height = parent.getHeight() - insets.top - insets.bottom;
+        boolean ltr = isLeftToRight();
+        if (getAutoCreateGaps() || getAutoCreateContainerGaps() ||
+                hasPreferredPaddingSprings) {
+            // Step 2: Calculate autopadding springs
+            calculateAutopadding(horizontalGroup, HORIZONTAL, SPECIFIC_SIZE, 0,
+                    width);
+            calculateAutopadding(verticalGroup, VERTICAL, SPECIFIC_SIZE, 0,
+                    height);
+        }
+        // Step 3: set the size of the groups.
+        horizontalGroup.setSize(HORIZONTAL, 0, width);
+        verticalGroup.setSize(VERTICAL, 0, height);
+        // Step 4: apply the size to the components.
+        for (ComponentInfo info : componentInfos.values()) {
+            info.setBounds(insets, width, ltr);
+        }
+    }
+
+    //
+    // LayoutManager2
+    //
+    /**
+     * Notification that a {@code Component} has been added to
+     * the parent container.  You should not invoke this method
+     * directly, instead you should use one of the {@code Group}
+     * methods to add a {@code Component}.
+     *
+     * @param component the component added
+     * @param constraints description of where to place the component
+     */
+    public void addLayoutComponent(Component component, Object constraints) {
+    }
+
+    /**
+     * Returns the maximum size for the specified container.
+     *
+     * @param parent the container to return the size for
+     * @return the maximum size for {@code parent}
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} that this was created with
+     * @throws IllegalStateException if any of the components added to
+     *         this layout are not in both a horizontal and vertical group
+     * @see java.awt.Container#getMaximumSize
+     */
+    public Dimension maximumLayoutSize(Container parent) {
+        checkParent(parent);
+        prepare(MAX_SIZE);
+        return adjustSize(horizontalGroup.getMaximumSize(HORIZONTAL),
+                verticalGroup.getMaximumSize(VERTICAL));
+    }
+
+    /**
+     * Returns the alignment along the x axis.  This specifies how
+     * the component would like to be aligned relative to other
+     * components.  The value should be a number between 0 and 1
+     * where 0 represents alignment along the origin, 1 is aligned
+     * the furthest away from the origin, 0.5 is centered, etc.
+     *
+     * @param parent the {@code Container} hosting this {@code LayoutManager}
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} that this was created with
+     * @return the alignment; this implementation returns {@code .5}
+     */
+    public float getLayoutAlignmentX(Container parent) {
+        checkParent(parent);
+        return .5f;
+    }
+
+    /**
+     * Returns the alignment along the y axis.  This specifies how
+     * the component would like to be aligned relative to other
+     * components.  The value should be a number between 0 and 1
+     * where 0 represents alignment along the origin, 1 is aligned
+     * the furthest away from the origin, 0.5 is centered, etc.
+     *
+     * @param parent the {@code Container} hosting this {@code LayoutManager}
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} that this was created with
+     * @return alignment; this implementation returns {@code .5}
+     */
+    public float getLayoutAlignmentY(Container parent) {
+        checkParent(parent);
+        return .5f;
+    }
+
+    /**
+     * Invalidates the layout, indicating that if the layout manager
+     * has cached information it should be discarded.
+     *
+     * @param parent the {@code Container} hosting this LayoutManager
+     * @throws IllegalArgumentException if {@code parent} is not
+     *         the same {@code Container} that this was created with
+     */
+    public void invalidateLayout(Container parent) {
+        checkParent(parent);
+        // invalidateLayout is called from Container.invalidate, which
+        // does NOT grab the treelock.  All other methods do.  To make sure
+        // there aren't any possible threading problems we grab the tree lock
+        // here.
+        synchronized(parent.getTreeLock()) {
+            isValid = false;
+        }
+    }
+
+    private void prepare(int sizeType) {
+        boolean visChanged = false;
+        // Step 1: If not-valid, clear springs and update visibility.
+        if (!isValid) {
+            isValid = true;
+            horizontalGroup.setSize(HORIZONTAL, UNSET, UNSET);
+            verticalGroup.setSize(VERTICAL, UNSET, UNSET);
+            for (ComponentInfo ci : componentInfos.values()) {
+                if (ci.updateVisibility()) {
+                    visChanged = true;
+                }
+                ci.clearCachedSize();
+            }
+        }
+        // Step 2: Make sure components are bound to ComponentInfos
+        if (springsChanged) {
+            registerComponents(horizontalGroup, HORIZONTAL);
+            registerComponents(verticalGroup, VERTICAL);
+        }
+        // Step 3: Adjust the autopadding. This removes existing
+        // autopadding, then recalculates where it should go.
+        if (springsChanged || visChanged) {
+            checkComponents();
+            horizontalGroup.removeAutopadding();
+            verticalGroup.removeAutopadding();
+            if (getAutoCreateGaps()) {
+                insertAutopadding(true);
+            } else if (hasPreferredPaddingSprings ||
+                    getAutoCreateContainerGaps()) {
+                insertAutopadding(false);
+            }
+            springsChanged = false;
+        }
+        // Step 4: (for min/pref/max size calculations only) calculate the
+        // autopadding. This invokes for unsetting the calculated values, then
+        // recalculating them.
+        // If sizeType == SPECIFIC_SIZE, it indicates we're doing layout, this
+        // step will be done later on.
+        if (sizeType != SPECIFIC_SIZE && (getAutoCreateGaps() ||
+                getAutoCreateContainerGaps() || hasPreferredPaddingSprings)) {
+            calculateAutopadding(horizontalGroup, HORIZONTAL, sizeType, 0, 0);
+            calculateAutopadding(verticalGroup, VERTICAL, sizeType, 0, 0);
+        }
+    }
+
+    private void calculateAutopadding(Group group, int axis, int sizeType,
+            int origin, int size) {
+        group.unsetAutopadding();
+        switch(sizeType) {
+            case MIN_SIZE:
+                size = group.getMinimumSize(axis);
+                break;
+            case PREF_SIZE:
+                size = group.getPreferredSize(axis);
+                break;
+            case MAX_SIZE:
+                size = group.getMaximumSize(axis);
+                break;
+            default:
+                break;
+        }
+        group.setSize(axis, origin, size);
+        group.calculateAutopadding(axis);
+    }
+
+    private void checkComponents() {
+        for (ComponentInfo info : componentInfos.values()) {
+            if (info.horizontalSpring == null) {
+                throw new IllegalStateException(info.component +
+                        " is not attached to a horizontal group");
+            }
+            if (info.verticalSpring == null) {
+                throw new IllegalStateException(info.component +
+                        " is not attached to a vertical group");
+            }
+        }
+    }
+
+    private void registerComponents(Group group, int axis) {
+        List<Spring> springs = group.springs;
+        for (int counter = springs.size() - 1; counter >= 0; counter--) {
+            Spring spring = springs.get(counter);
+            if (spring instanceof ComponentSpring) {
+                ((ComponentSpring)spring).installIfNecessary(axis);
+            } else if (spring instanceof Group) {
+                registerComponents((Group)spring, axis);
+            }
+        }
+    }
+
+    private Dimension adjustSize(int width, int height) {
+        Insets insets = host.getInsets();
+        return new Dimension(width + insets.left + insets.right,
+                height + insets.top + insets.bottom);
+    }
+
+    private void checkParent(Container parent) {
+        if (parent != host) {
+            throw new IllegalArgumentException(
+                    "GroupLayout can only be used with one Container at a time");
+        }
+    }
+
+    /**
+     * Returns the {@code ComponentInfo} for the specified Component,
+     * creating one if necessary.
+     */
+    private ComponentInfo getComponentInfo(Component component) {
+        ComponentInfo info = (ComponentInfo)componentInfos.get(component);
+        if (info == null) {
+            info = new ComponentInfo(component);
+            componentInfos.put(component, info);
+            if (component.getParent() != host) {
+                host.add(component);
+            }
+        }
+        return info;
+    }
+
+    /**
+     * Adjusts the autopadding springs for the horizontal and vertical
+     * groups.  If {@code insert} is {@code true} this will insert auto padding
+     * springs, otherwise this will only adjust the springs that
+     * comprise auto preferred padding springs.
+     */
+    private void insertAutopadding(boolean insert) {
+        horizontalGroup.insertAutopadding(HORIZONTAL,
+                new ArrayList<AutoPreferredGapSpring>(1),
+                new ArrayList<AutoPreferredGapSpring>(1),
+                new ArrayList<ComponentSpring>(1),
+                new ArrayList<ComponentSpring>(1), insert);
+        verticalGroup.insertAutopadding(VERTICAL,
+                new ArrayList<AutoPreferredGapSpring>(1),
+                new ArrayList<AutoPreferredGapSpring>(1),
+                new ArrayList<ComponentSpring>(1),
+                new ArrayList<ComponentSpring>(1), insert);
+    }
+
+    /**
+     * Returns {@code true} if the two Components have a common ParallelGroup
+     * ancestor along the particular axis.
+     */
+    private boolean areParallelSiblings(Component source, Component target,
+            int axis) {
+        ComponentInfo sourceInfo = getComponentInfo(source);
+        ComponentInfo targetInfo = getComponentInfo(target);
+        Spring sourceSpring;
+        Spring targetSpring;
+        if (axis == HORIZONTAL) {
+            sourceSpring = sourceInfo.horizontalSpring;
+            targetSpring = targetInfo.horizontalSpring;
+        } else {
+            sourceSpring = sourceInfo.verticalSpring;
+            targetSpring = targetInfo.verticalSpring;
+        }
+        Set<Spring> sourcePath = tmpParallelSet;
+        sourcePath.clear();
+        Spring spring = sourceSpring.getParent();
+        while (spring != null) {
+            sourcePath.add(spring);
+            spring = spring.getParent();
+        }
+        spring = targetSpring.getParent();
+        while (spring != null) {
+            if (sourcePath.contains(spring)) {
+                sourcePath.clear();
+                while (spring != null) {
+                    if (spring instanceof ParallelGroup) {
+                        return true;
+                    }
+                    spring = spring.getParent();
+                }
+                return false;
+            }
+            spring = spring.getParent();
+        }
+        sourcePath.clear();
+        return false;
+    }
+
+    private boolean isLeftToRight() {
+        return host.getComponentOrientation().isLeftToRight();
+    }
+
+    /**
+     * Returns a string representation of this {@code GroupLayout}.
+     * This method is intended to be used for debugging purposes,
+     * and the content and format of the returned string may vary
+     * between implementations.
+     *
+     * @return a string representation of this {@code GroupLayout}
+     **/
+    public String toString() {
+        if (springsChanged) {
+            registerComponents(horizontalGroup, HORIZONTAL);
+            registerComponents(verticalGroup, VERTICAL);
+        }
+        StringBuffer buffer = new StringBuffer();
+        buffer.append("HORIZONTAL\n");
+        createSpringDescription(buffer, horizontalGroup, "  ", HORIZONTAL);
+        buffer.append("\nVERTICAL\n");
+        createSpringDescription(buffer, verticalGroup, "  ", VERTICAL);
+        return buffer.toString();
+    }
+
+    private void createSpringDescription(StringBuffer buffer, Spring spring,
+            String indent, int axis) {
+        String origin = "";
+        String padding = "";
+        if (spring instanceof ComponentSpring) {
+            ComponentSpring cSpring = (ComponentSpring)spring;
+            origin = Integer.toString(cSpring.getOrigin()) + " ";
+            String name = cSpring.getComponent().getName();
+            if (name != null) {
+                origin = "name=" + name + ", ";
+            }
+        }
+        if (spring instanceof AutoPreferredGapSpring) {
+            AutoPreferredGapSpring paddingSpring =
+                    (AutoPreferredGapSpring)spring;
+            padding = ", userCreated=" + paddingSpring.getUserCreated() +
+                    ", matches=" + paddingSpring.getMatchDescription();
+        }
+        buffer.append(indent + spring.getClass().getName() + " " +
+                Integer.toHexString(spring.hashCode()) + " " +
+                origin +
+                ", size=" + spring.getSize() +
+                ", alignment=" + spring.getAlignment() +
+                " prefs=[" + spring.getMinimumSize(axis) +
+                " " + spring.getPreferredSize(axis) +
+                " " + spring.getMaximumSize(axis) +
+                padding + "]\n");
+        if (spring instanceof Group) {
+            List<Spring> springs = ((Group)spring).springs;
+            indent += "  ";
+            for (int counter = 0; counter < springs.size(); counter++) {
+                createSpringDescription(buffer, springs.get(counter), indent,
+                        axis);
+            }
+        }
+    }
+
+
+    /**
+     * Spring consists of a range: min, pref and max, a value some where in
+     * the middle of that, and a location. Spring caches the
+     * min/max/pref.  If the min/pref/max has internally changes, or needs
+     * to be updated you must invoke clear.
+     */
+    private abstract class Spring {
+        private int size;
+        private int min;
+        private int max;
+        private int pref;
+        private Spring parent;
+
+        private Alignment alignment;
+
+        Spring() {
+            min = pref = max = UNSET;
+        }
+
+        /**
+         * Calculates and returns the minimum size.
+         *
+         * @param axis the axis of layout; one of HORIZONTAL or VERTICAL
+         * @return the minimum size
+         */
+        abstract int calculateMinimumSize(int axis);
+
+        /**
+         * Calculates and returns the preferred size.
+         *
+         * @param axis the axis of layout; one of HORIZONTAL or VERTICAL
+         * @return the preferred size
+         */
+        abstract int calculatePreferredSize(int axis);
+
+        /**
+         * Calculates and returns the minimum size.
+         *
+         * @param axis the axis of layout; one of HORIZONTAL or VERTICAL
+         * @return the minimum size
+         */
+        abstract int calculateMaximumSize(int axis);
+
+        /**
+         * Sets the parent of this Spring.
+         */
+        void setParent(Spring parent) {
+            this.parent = parent;
+        }
+
+        /**
+         * Returns the parent of this spring.
+         */
+        Spring getParent() {
+            return parent;
+        }
+
+        // This is here purely as a conveniance for ParallelGroup to avoid
+        // having to track alignment separately.
+        void setAlignment(Alignment alignment) {
+            this.alignment = alignment;
+        }
+
+        /**
+         * Alignment for this Spring, this may be null.
+         */
+        Alignment getAlignment() {
+            return alignment;
+        }
+
+        /**
+         * Returns the minimum size.
+         */
+        final int getMinimumSize(int axis) {
+            if (min == UNSET) {
+                min = constrain(calculateMinimumSize(axis));
+            }
+            return min;
+        }
+
+        /**
+         * Returns the preferred size.
+         */
+        final int getPreferredSize(int axis) {
+            if (pref == UNSET) {
+                pref = constrain(calculatePreferredSize(axis));
+            }
+            return pref;
+        }
+
+        /**
+         * Returns the maximum size.
+         */
+        final int getMaximumSize(int axis) {
+            if (max == UNSET) {
+                max = constrain(calculateMaximumSize(axis));
+            }
+            return max;
+        }
+
+        /**
+         * Sets the value and location of the spring.  Subclasses
+         * will want to invoke super, then do any additional sizing.
+         *
+         * @param axis HORIZONTAL or VERTICAL
+         * @param origin of this Spring
+         * @param size of the Spring.  If size is UNSET, this invokes
+         *        clear.
+         */
+        void setSize(int axis, int origin, int size) {
+            this.size = size;
+            if (size == UNSET) {
+                unset();
+            }
+        }
+
+        /**
+         * Resets the cached min/max/pref.
+         */
+        void unset() {
+            size = min = pref = max = UNSET;
+        }
+
+        /**
+         * Returns the current size.
+         */
+        int getSize() {
+            return size;
+        }
+
+        int constrain(int value) {
+            return Math.min(value, Short.MAX_VALUE);
+        }
+
+        int getBaseline() {
+            return -1;
+        }
+
+        BaselineResizeBehavior getBaselineResizeBehavior() {
+            return BaselineResizeBehavior.OTHER;
+        }
+
+        final boolean isResizable(int axis) {
+            int min = getMinimumSize(axis);
+            int pref = getPreferredSize(axis);
+            return (min != pref || pref != getMaximumSize(axis));
+        }
+
+        /**
+         * Returns {@code true} if this spring will ALWAYS have a zero
+         * size. This should NOT check the current size, rather it's
+         * meant to quickly test if this Spring will always have a
+         * zero size.
+         *
+         * @param treatAutopaddingAsZeroSized if {@code true}, auto padding
+         *        springs should be treated as having a size of {@code 0}
+         * @return {@code true} if this spring will have a zero size,
+         *         {@code false} otherwise
+         */
+        abstract boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized);
+    }
+
+    /**
+     * {@code Group} provides the basis for the two types of
+     * operations supported by {@code GroupLayout}: laying out
+     * components one after another ({@link SequentialGroup SequentialGroup})
+     * or aligned ({@link ParallelGroup ParallelGroup}). {@code Group} and
+     * its subclasses have no public constructor; to create one use
+     * one of {@code createSequentialGroup} or
+     * {@code createParallelGroup}. Additionally, taking a {@code Group}
+     * created from one {@code GroupLayout} and using it with another
+     * will produce undefined results.
+     * <p>
+     * Various methods in {@code Group} and its subclasses allow you
+     * to explicitly specify the range. The arguments to these methods
+     * can take two forms, either a value greater than or equal to 0,
+     * or one of {@code DEFAULT_SIZE} or {@code PREFERRED_SIZE}. A
+     * value greater than or equal to {@code 0} indicates a specific
+     * size. {@code DEFAULT_SIZE} indicates the corresponding size
+     * from the component should be used.  For example, if {@code
+     * DEFAULT_SIZE} is passed as the minimum size argument, the
+     * minimum size is obtained from invoking {@code getMinimumSize}
+     * on the component. Likewise, {@code PREFERRED_SIZE} indicates
+     * the value from {@code getPreferredSize} should be used.
+     * The following example adds {@code myComponent} to {@code group}
+     * with specific values for the range. That is, the minimum is
+     * explicitly specified as 100, preferred as 200, and maximum as
+     * 300.
+     * <pre>
+     *   group.addComponent(myComponent, 100, 200, 300);
+     * </pre>
+     * The following example adds {@code myComponent} to {@code group} using
+     * a combination of the forms. The minimum size is forced to be the
+     * same as the preferred size, the preferred size is determined by
+     * using {@code myComponent.getPreferredSize} and the maximum is
+     * determined by invoking {@code getMaximumSize} on the component.
+     * <pre>
+     *   group.addComponent(myComponent, GroupLayout.PREFERRED_SIZE,
+     *             GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE);
+     * </pre>
+     * <p>
+     * Unless otherwise specified all the methods of {@code Group} and
+     * its subclasses that allow you to specify a range throw an
+     * {@code IllegalArgumentException} if passed an invalid range. An
+     * invalid range is one in which any of the values are &lt; 0 and
+     * not one of {@code PREFERRED_SIZE} or {@code DEFAULT_SIZE}, or
+     * the following is not met (for specific values): {@code min}
+     * &lt;= {@code pref} &lt;= {@code max}.
+     * <p>
+     * Similarly any methods that take a {@code Component} throw a
+     * {@code NullPointerException} if passed {@code null} and any methods
+     * that take a {@code Group} throw an {@code IllegalArgumentException} if
+     * passed {@code null}.
+     *
+     * @see #createSequentialGroup
+     * @see #createParallelGroup
+     * @since 1.6
+     */
+    public abstract class Group extends Spring {
+        // private int origin;
+        // private int size;
+        List<Spring> springs;
+
+        Group() {
+            springs = new ArrayList<Spring>();
+        }
+
+        /**
+         * Adds a {@code Group} to this {@code Group}.
+         *
+         * @param group the {@code Group} to add
+         * @return this {@code Group}
+         */
+        public Group addGroup(Group group) {
+            return addSpring(group);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code Group}.
+         *
+         * @param component the {@code Component} to add
+         * @return this {@code Group}
+         */
+        public Group addComponent(Component component) {
+            return addComponent(component, DEFAULT_SIZE, DEFAULT_SIZE,
+                    DEFAULT_SIZE);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code Group}
+         * with the specified size.
+         *
+         * @param component the {@code Component} to add
+         * @param min the minimum size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @param pref the preferred size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @param max the maximum size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @return this {@code Group}
+         */
+        public Group addComponent(Component component, int min, int pref,
+                int max) {
+            return addSpring(new ComponentSpring(component, min, pref, max));
+        }
+
+        /**
+         * Adds a rigid gap to this {@code Group}.
+         *
+         * @param size the size of the gap
+         * @return this {@code Group}
+         * @throws IllegalArgumentException if {@code size} is less than
+         *         {@code 0}
+         */
+        public Group addGap(int size) {
+            return addGap(size, size, size);
+        }
+
+        /**
+         * Adds a gap to this {@code Group} with the specified size.
+         *
+         * @param min the minimum size of the gap
+         * @param pref the preferred size of the gap
+         * @param max the maximum size of the gap
+         * @throws IllegalArgumentException if any of the values are
+         *         less than {@code 0}
+         * @return this {@code Group}
+         */
+        public Group addGap(int min, int pref, int max) {
+            return addSpring(new GapSpring(min, pref, max));
+        }
+
+        Spring getSpring(int index) {
+            return springs.get(index);
+        }
+
+        int indexOf(Spring spring) {
+            return springs.indexOf(spring);
+        }
+
+        /**
+         * Adds the Spring to the list of {@code Spring}s and returns
+         * the receiver.
+         */
+        Group addSpring(Spring spring) {
+            springs.add(spring);
+            spring.setParent(this);
+            if (!(spring instanceof AutoPreferredGapSpring) ||
+                    !((AutoPreferredGapSpring)spring).getUserCreated()) {
+                springsChanged = true;
+            }
+            return this;
+        }
+
+        //
+        // Spring methods
+        //
+
+        void setSize(int axis, int origin, int size) {
+            super.setSize(axis, origin, size);
+            if (size == UNSET) {
+                for (int counter = springs.size() - 1; counter >= 0;
+                counter--) {
+                    getSpring(counter).setSize(axis, origin, size);
+                }
+            } else {
+                setValidSize(axis, origin, size);
+            }
+        }
+
+        /**
+         * This is invoked from {@code setSize} if passed a value
+         * other than UNSET.
+         */
+        abstract void setValidSize(int axis, int origin, int size);
+
+        int calculateMinimumSize(int axis) {
+            return calculateSize(axis, MIN_SIZE);
+        }
+
+        int calculatePreferredSize(int axis) {
+            return calculateSize(axis, PREF_SIZE);
+        }
+
+        int calculateMaximumSize(int axis) {
+            return calculateSize(axis, MAX_SIZE);
+        }
+
+        /**
+         * Calculates the specified size.  This is called from
+         * one of the {@code getMinimumSize0},
+         * {@code getPreferredSize0} or
+         * {@code getMaximumSize0} methods.  This will invoke
+         * to {@code operator} to combine the values.
+         */
+        int calculateSize(int axis, int type) {
+            int count = springs.size();
+            if (count == 0) {
+                return 0;
+            }
+            if (count == 1) {
+                return getSpringSize(getSpring(0), axis, type);
+            }
+            int size = constrain(operator(getSpringSize(getSpring(0), axis,
+                    type), getSpringSize(getSpring(1), axis, type)));
+            for (int counter = 2; counter < count; counter++) {
+                size = constrain(operator(size, getSpringSize(
+                        getSpring(counter), axis, type)));
+            }
+            return size;
+        }
+
+        int getSpringSize(Spring spring, int axis, int type) {
+            switch(type) {
+                case MIN_SIZE:
+                    return spring.getMinimumSize(axis);
+                case PREF_SIZE:
+                    return spring.getPreferredSize(axis);
+                case MAX_SIZE:
+                    return spring.getMaximumSize(axis);
+            }
+            assert false;
+            return 0;
+        }
+
+        /**
+         * Used to compute how the two values representing two springs
+         * will be combined.  For example, a group that layed things out
+         * one after the next would return {@code a + b}.
+         */
+        abstract int operator(int a, int b);
+
+        //
+        // Padding
+        //
+
+        /**
+         * Adjusts the autopadding springs in this group and its children.
+         * If {@code insert} is true this will insert auto padding
+         * springs, otherwise this will only adjust the springs that
+         * comprise auto preferred padding springs.
+         *
+         * @param axis the axis of the springs; HORIZONTAL or VERTICAL
+         * @param leadingPadding List of AutopaddingSprings that occur before
+         *                       this Group
+         * @param trailingPadding any trailing autopadding springs are added
+         *                        to this on exit
+         * @param leading List of ComponentSprings that occur before this Group
+         * @param trailing any trailing ComponentSpring are added to this
+         *                 List
+         * @param insert Whether or not to insert AutopaddingSprings or just
+         *               adjust any existing AutopaddingSprings.
+         */
+        abstract void insertAutopadding(int axis,
+                List<AutoPreferredGapSpring> leadingPadding,
+                List<AutoPreferredGapSpring> trailingPadding,
+                List<ComponentSpring> leading, List<ComponentSpring> trailing,
+                boolean insert);
+
+        /**
+         * Removes any AutopaddingSprings for this Group and its children.
+         */
+        void removeAutopadding() {
+            unset();
+            for (int counter = springs.size() - 1; counter >= 0; counter--) {
+                Spring spring = springs.get(counter);
+                if (spring instanceof AutoPreferredGapSpring) {
+                    if (((AutoPreferredGapSpring)spring).getUserCreated()) {
+                        ((AutoPreferredGapSpring)spring).reset();
+                    } else {
+                        springs.remove(counter);
+                    }
+                } else if (spring instanceof Group) {
+                    ((Group)spring).removeAutopadding();
+                }
+            }
+        }
+
+        void unsetAutopadding() {
+            // Clear cached pref/min/max.
+            unset();
+            for (int counter = springs.size() - 1; counter >= 0; counter--) {
+                Spring spring = springs.get(counter);
+                if (spring instanceof AutoPreferredGapSpring) {
+                    ((AutoPreferredGapSpring)spring).unset();
+                } else if (spring instanceof Group) {
+                    ((Group)spring).unsetAutopadding();
+                }
+            }
+        }
+
+        void calculateAutopadding(int axis) {
+            for (int counter = springs.size() - 1; counter >= 0; counter--) {
+                Spring spring = springs.get(counter);
+                if (spring instanceof AutoPreferredGapSpring) {
+                    // Force size to be reset.
+                    spring.unset();
+                    ((AutoPreferredGapSpring)spring).calculatePadding(axis);
+                } else if (spring instanceof Group) {
+                    ((Group)spring).calculateAutopadding(axis);
+                }
+            }
+            // Clear cached pref/min/max.
+            unset();
+        }
+
+        @Override
+        boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized) {
+            for (int i = springs.size() - 1; i >= 0; i--) {
+                Spring spring = springs.get(i);
+                if (!spring.willHaveZeroSize(treatAutopaddingAsZeroSized)) {
+                    return false;
+                }
+            }
+            return true;
+        }
+    }
+
+
+    /**
+     * A {@code Group} that positions and sizes its elements
+     * sequentially, one after another.  This class has no public
+     * constructor, use the {@code createSequentialGroup} method
+     * to create one.
+     * <p>
+     * In order to align a {@code SequentialGroup} along the baseline
+     * of a baseline aligned {@code ParallelGroup} you need to specify
+     * which of the elements of the {@code SequentialGroup} is used to
+     * determine the baseline.  The element used to calculate the
+     * baseline is specified using one of the {@code add} methods that
+     * take a {@code boolean}. The last element added with a value of
+     * {@code true} for {@code useAsBaseline} is used to calculate the
+     * baseline.
+     *
+     * @see #createSequentialGroup
+     * @since 1.6
+     */
+    public class SequentialGroup extends Group {
+        private Spring baselineSpring;
+
+        SequentialGroup() {
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public SequentialGroup addGroup(Group group) {
+            return (SequentialGroup)super.addGroup(group);
+        }
+
+        /**
+         * Adds a {@code Group} to this {@code Group}.
+         *
+         * @param group the {@code Group} to add
+         * @param useAsBaseline whether the specified {@code Group} should
+         *        be used to calculate the baseline for this {@code Group}
+         * @return this {@code Group}
+         */
+        public SequentialGroup addGroup(boolean useAsBaseline, Group group) {
+            super.addGroup(group);
+            if (useAsBaseline) {
+                baselineSpring = group;
+            }
+            return this;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public SequentialGroup addComponent(Component component) {
+            return (SequentialGroup)super.addComponent(component);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code Group}.
+         *
+         * @param useAsBaseline whether the specified {@code Component} should
+         *        be used to calculate the baseline for this {@code Group}
+         * @param component the {@code Component} to add
+         * @return this {@code Group}
+         */
+        public SequentialGroup addComponent(boolean useAsBaseline,
+                Component component) {
+            super.addComponent(component);
+            if (useAsBaseline) {
+                baselineSpring = springs.get(springs.size() - 1);
+            }
+            return this;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public SequentialGroup addComponent(Component component, int min,
+                int pref, int max) {
+            return (SequentialGroup)super.addComponent(
+                    component, min, pref, max);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code Group}
+         * with the specified size.
+         *
+         * @param useAsBaseline whether the specified {@code Component} should
+         *        be used to calculate the baseline for this {@code Group}
+         * @param component the {@code Component} to add
+         * @param min the minimum size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @param pref the preferred size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @param max the maximum size or one of {@code DEFAULT_SIZE} or
+         *            {@code PREFERRED_SIZE}
+         * @return this {@code Group}
+         */
+        public SequentialGroup addComponent(boolean useAsBaseline,
+                Component component, int min, int pref, int max) {
+            super.addComponent(component, min, pref, max);
+            if (useAsBaseline) {
+                baselineSpring = springs.get(springs.size() - 1);
+            }
+            return this;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public SequentialGroup addGap(int size) {
+            return (SequentialGroup)super.addGap(size);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public SequentialGroup addGap(int min, int pref, int max) {
+            return (SequentialGroup)super.addGap(min, pref, max);
+        }
+
+        /**
+         * Adds an element representing the preferred gap between two
+         * components. The element created to represent the gap is not
+         * resizable.
+         *
+         * @param comp1 the first component
+         * @param comp2 the second component
+         * @param type the type of gap; one of the constants defined by
+         *        {@code LayoutStyle}
+         * @return this {@code SequentialGroup}
+         * @throws IllegalArgumentException if {@code type}, {@code comp1} or
+         *         {@code comp2} is {@code null}
+         * @see LayoutStyle
+         */
+        public SequentialGroup addPreferredGap(JComponent comp1,
+                JComponent comp2, ComponentPlacement type) {
+            return addPreferredGap(comp1, comp2, type, DEFAULT_SIZE,
+                    PREFERRED_SIZE);
+        }
+
+        /**
+         * Adds an element representing the preferred gap between two
+         * components.
+         *
+         * @param comp1 the first component
+         * @param comp2 the second component
+         * @param type the type of gap
+         * @param pref the preferred size of the grap; one of
+         *        {@code DEFAULT_SIZE} or a value &gt;= 0
+         * @param max the maximum size of the gap; one of
+         *        {@code DEFAULT_SIZE}, {@code PREFERRED_SIZE}
+         *        or a value &gt;= 0
+         * @return this {@code SequentialGroup}
+         * @throws IllegalArgumentException if {@code type}, {@code comp1} or
+         *         {@code comp2} is {@code null}
+         * @see LayoutStyle
+         */
+        public SequentialGroup addPreferredGap(JComponent comp1,
+                JComponent comp2, ComponentPlacement type, int pref,
+                int max) {
+            if (type == null) {
+                throw new IllegalArgumentException("Type must be non-null");
+            }
+            if (comp1 == null || comp2 == null) {
+                throw new IllegalArgumentException(
+                        "Components must be non-null");
+            }
+            checkPreferredGapValues(pref, max);
+            return (SequentialGroup)addSpring(new PreferredGapSpring(
+                    comp1, comp2, type, pref, max));
+        }
+
+        /**
+         * Adds an element representing the preferred gap between the
+         * nearest components.  During layout, neighboring
+         * components are found, and the size of the added gap is set
+         * based on the preferred gap between the components.  If no
+         * neighboring components are found the gap has a size of {@code 0}.
+         * <p>
+         * The element created to represent the gap is not
+         * resizable.
+         *
+         * @param type the type of gap; one of
+         *        {@code LayoutStyle.ComponentPlacement.RELATED} or
+         *        {@code LayoutStyle.ComponentPlacement.UNRELATED}
+         * @return this {@code SequentialGroup}
+         * @see LayoutStyle
+         * @throws IllegalArgumentException if {@code type} is not one of
+         *         {@code LayoutStyle.ComponentPlacement.RELATED} or
+         *         {@code LayoutStyle.ComponentPlacement.UNRELATED}
+         */
+        public SequentialGroup addPreferredGap(ComponentPlacement type) {
+            return addPreferredGap(type, DEFAULT_SIZE, DEFAULT_SIZE);
+        }
+
+        /**
+         * Adds an element representing the preferred gap between the
+         * nearest components.  During layout, neighboring
+         * components are found, and the minimum of this
+         * gap is set based on the size of the preferred gap between the
+         * neighboring components.  If no neighboring components are found the
+         * minimum size is set to 0.
+         *
+         * @param type the type of gap; one of
+         *        {@code LayoutStyle.ComponentPlacement.RELATED} or
+         *        {@code LayoutStyle.ComponentPlacement.UNRELATED}
+         * @param pref the preferred size of the grap; one of
+         *        {@code DEFAULT_SIZE} or a value &gt;= 0
+         * @param max the maximum size of the gap; one of
+         *        {@code DEFAULT_SIZE}, {@code PREFERRED_SIZE}
+         *        or a value &gt;= 0
+         * @return this {@code SequentialGroup}
+         * @throws IllegalArgumentException if {@code type} is not one of
+         *         {@code LayoutStyle.ComponentPlacement.RELATED} or
+         *         {@code LayoutStyle.ComponentPlacement.UNRELATED}
+         * @see LayoutStyle
+         */
+        public SequentialGroup addPreferredGap(ComponentPlacement type,
+                int pref, int max) {
+            if (type != ComponentPlacement.RELATED &&
+                    type != ComponentPlacement.UNRELATED) {
+                throw new IllegalArgumentException(
+                        "Type must be one of " +
+                        "LayoutStyle.ComponentPlacement.RELATED or " +
+                        "LayoutStyle.ComponentPlacement.UNRELATED");
+            }
+            checkPreferredGapValues(pref, max);
+            hasPreferredPaddingSprings = true;
+            return (SequentialGroup)addSpring(new AutoPreferredGapSpring(
+                    type, pref, max));
+        }
+
+        /**
+         * Adds an element representing the preferred gap between an edge
+         * the container and components that touch the border of the
+         * container. This has no effect if the added gap does not
+         * touch an edge of the parent container.
+         * <p>
+         * The element created to represent the gap is not
+         * resizable.
+         *
+         * @return this {@code SequentialGroup}
+         */
+        public SequentialGroup addContainerGap() {
+            return addContainerGap(DEFAULT_SIZE, DEFAULT_SIZE);
+        }
+
+        /**
+         * Adds an element representing the preferred gap between one
+         * edge of the container and the next or previous {@code
+         * Component} with the specified size. This has no
+         * effect if the next or previous element is not a {@code
+         * Component} and does not touch one edge of the parent
+         * container.
+         *
+         * @param pref the preferred size; one of {@code DEFAULT_SIZE} or a
+         *              value &gt;= 0
+         * @param max the maximum size; one of {@code DEFAULT_SIZE},
+         *        {@code PREFERRED_SIZE} or a value &gt;= 0
+         * @return this {@code SequentialGroup}
+         */
+        public SequentialGroup addContainerGap(int pref, int max) {
+            if ((pref < 0 && pref != DEFAULT_SIZE) ||
+                    (max < 0 && max != DEFAULT_SIZE && max != PREFERRED_SIZE)||
+                    (pref >= 0 && max >= 0 && pref > max)) {
+                throw new IllegalArgumentException(
+                        "Pref and max must be either DEFAULT_VALUE " +
+                        "or >= 0 and pref <= max");
+            }
+            hasPreferredPaddingSprings = true;
+            return (SequentialGroup)addSpring(
+                    new ContainerAutoPreferredGapSpring(pref, max));
+        }
+
+        int operator(int a, int b) {
+            return constrain(a) + constrain(b);
+        }
+
+        void setValidSize(int axis, int origin, int size) {
+            int pref = getPreferredSize(axis);
+            if (size == pref) {
+                // Layout at preferred size
+                for (Spring spring : springs) {
+                    int springPref = spring.getPreferredSize(axis);
+                    spring.setSize(axis, origin, springPref);
+                    origin += springPref;
+                }
+            } else if (springs.size() == 1) {
+                Spring spring = getSpring(0);
+                spring.setSize(axis, origin, Math.min(
+                        Math.max(size, spring.getMinimumSize(axis)),
+                        spring.getMaximumSize(axis)));
+            } else if (springs.size() > 1) {
+                // Adjust between min/pref
+                setValidSizeNotPreferred(axis, origin, size);
+            }
+        }
+
+        private void setValidSizeNotPreferred(int axis, int origin, int size) {
+            int delta = size - getPreferredSize(axis);
+            assert delta != 0;
+            boolean useMin = (delta < 0);
+            int springCount = springs.size();
+            if (useMin) {
+                delta *= -1;
+            }
+
+            // The following algorithm if used for resizing springs:
+            // 1. Calculate the resizability of each spring (pref - min or
+            //    max - pref) into a list.
+            // 2. Sort the list in ascending order
+            // 3. Iterate through each of the resizable Springs, attempting
+            //    to give them (pref - size) / resizeCount
+            // 4. For any Springs that can not accomodate that much space
+            //    add the remainder back to the amount to distribute and
+            //    recalculate how must space the remaining springs will get.
+            // 5. Set the size of the springs.
+
+            // First pass, sort the resizable springs into the List resizable
+            List<SpringDelta> resizable = buildResizableList(axis, useMin);
+            int resizableCount = resizable.size();
+
+            if (resizableCount > 0) {
+                // How much we would like to give each Spring.
+                int sDelta = delta / resizableCount;
+                // Remaining space.
+                int slop = delta - sDelta * resizableCount;
+                int[] sizes = new int[springCount];
+                int sign = useMin ? -1 : 1;
+                // Second pass, accumulate the resulting deltas (relative to
+                // preferred) into sizes.
+                for (int counter = 0; counter < resizableCount; counter++) {
+                    SpringDelta springDelta = resizable.get(counter);
+                    if ((counter + 1) == resizableCount) {
+                        sDelta += slop;
+                    }
+                    springDelta.delta = Math.min(sDelta, springDelta.delta);
+                    delta -= springDelta.delta;
+                    if (springDelta.delta != sDelta && counter + 1 <
+                            resizableCount) {
+                        // Spring didn't take all the space, reset how much
+                        // each spring will get.
+                        sDelta = delta / (resizableCount - counter - 1);
+                        slop = delta - sDelta * (resizableCount - counter - 1);
+                    }
+                    sizes[springDelta.index] = sign * springDelta.delta;
+                }
+
+                // And finally set the size of each spring
+                for (int counter = 0; counter < springCount; counter++) {
+                    Spring spring = getSpring(counter);
+                    int sSize = spring.getPreferredSize(axis) + sizes[counter];
+                    spring.setSize(axis, origin, sSize);
+                    origin += sSize;
+                }
+            } else {
+                // Nothing resizable, use the min or max of each of the
+                // springs.
+                for (int counter = 0; counter < springCount; counter++) {
+                    Spring spring = getSpring(counter);
+                    int sSize;
+                    if (useMin) {
+                        sSize = spring.getMinimumSize(axis);
+                    } else {
+                        sSize = spring.getMaximumSize(axis);
+                    }
+                    spring.setSize(axis, origin, sSize);
+                    origin += sSize;
+                }
+            }
+        }
+
+        /**
+         * Returns the sorted list of SpringDelta's for the current set of
+         * Springs. The list is ordered based on the amount of flexibility of
+         * the springs.
+         */
+        private List<SpringDelta> buildResizableList(int axis,
+                boolean useMin) {
+            // First pass, figure out what is resizable
+            int size = springs.size();
+            List<SpringDelta> sorted = new ArrayList<SpringDelta>(size);
+            for (int counter = 0; counter < size; counter++) {
+                Spring spring = getSpring(counter);
+                int sDelta;
+                if (useMin) {
+                    sDelta = spring.getPreferredSize(axis) -
+                            spring.getMinimumSize(axis);
+                } else {
+                    sDelta = spring.getMaximumSize(axis) -
+                            spring.getPreferredSize(axis);
+                }
+                if (sDelta > 0) {
+                    sorted.add(new SpringDelta(counter, sDelta));
+                }
+            }
+            Collections.sort(sorted);
+            return sorted;
+        }
+
+        private int indexOfNextNonZeroSpring(
+                int index, boolean treatAutopaddingAsZeroSized) {
+            while (index < springs.size()) {
+                Spring spring = springs.get(index);
+                if (!spring.willHaveZeroSize(treatAutopaddingAsZeroSized)) {
+                    return index;
+                }
+                index++;
+            }
+            return index;
+        }
+
+        @Override
+        void insertAutopadding(int axis,
+                List<AutoPreferredGapSpring> leadingPadding,
+                List<AutoPreferredGapSpring> trailingPadding,
+                List<ComponentSpring> leading, List<ComponentSpring> trailing,
+                boolean insert) {
+            List<AutoPreferredGapSpring> newLeadingPadding =
+                    new ArrayList<AutoPreferredGapSpring>(leadingPadding);
+            List<AutoPreferredGapSpring> newTrailingPadding =
+                    new ArrayList<AutoPreferredGapSpring>(1);
+            List<ComponentSpring> newLeading =
+                    new ArrayList<ComponentSpring>(leading);
+            List<ComponentSpring> newTrailing = null;
+            int counter = 0;
+            // Warning, this must use springs.size, as it may change during the
+            // loop.
+            while (counter < springs.size()) {
+                Spring spring = getSpring(counter);
+                if (spring instanceof AutoPreferredGapSpring) {
+                    if (newLeadingPadding.size() == 0) {
+                        // Autopadding spring. Set the sources of the
+                        // autopadding spring based on newLeading.
+                        AutoPreferredGapSpring padding =
+                            (AutoPreferredGapSpring)spring;
+                        padding.setSources(newLeading);
+                        newLeading.clear();
+                        counter = indexOfNextNonZeroSpring(counter + 1, true);
+                        if (counter == springs.size()) {
+                            // Last spring in the list, add it to
+                            // trailingPadding.
+                            if (!(padding instanceof
+                                  ContainerAutoPreferredGapSpring)) {
+                                trailingPadding.add(padding);
+                            }
+                        } else {
+                            newLeadingPadding.clear();
+                            newLeadingPadding.add(padding);
+                        }
+                    } else {
+                        counter = indexOfNextNonZeroSpring(counter + 1, true);
+                    }
+                } else {
+                    // Not a padding spring
+                    if (newLeading.size() > 0 && insert) {
+                        // There's leading ComponentSprings, create an
+                        // autopadding spring.
+                        AutoPreferredGapSpring padding =
+                                new AutoPreferredGapSpring();
+                        // Force the newly created spring to be considered
+                        // by NOT incrementing counter
+                        springs.add(counter, padding);
+                        continue;
+                    }
+                    if (spring instanceof ComponentSpring) {
+                        // Spring is a Component, make it the target of any
+                        // leading AutopaddingSpring.
+                        ComponentSpring cSpring = (ComponentSpring)spring;
+                        if (!cSpring.isVisible()) {
+                            counter++;
+                            continue;
+                        }
+                        for (AutoPreferredGapSpring gapSpring : newLeadingPadding) {
+                            gapSpring.addTarget(cSpring, axis);
+                        }
+                        newLeading.clear();
+                        newLeadingPadding.clear();
+                        counter = indexOfNextNonZeroSpring(counter + 1, false);
+                        if (counter == springs.size()) {
+                            // Last Spring, add it to trailing
+                            trailing.add(cSpring);
+                        } else {
+                            // Not that last Spring, add it to leading
+                            newLeading.add(cSpring);
+                        }
+                    } else if (spring instanceof Group) {
+                        // Forward call to child Group
+                        if (newTrailing == null) {
+                            newTrailing = new ArrayList<ComponentSpring>(1);
+                        } else {
+                            newTrailing.clear();
+                        }
+                        newTrailingPadding.clear();
+                        ((Group)spring).insertAutopadding(axis,
+                                newLeadingPadding, newTrailingPadding,
+                                newLeading, newTrailing, insert);
+                        newLeading.clear();
+                        newLeadingPadding.clear();
+                        counter = indexOfNextNonZeroSpring(
+                                    counter + 1, (newTrailing.size() == 0));
+                        if (counter == springs.size()) {
+                            trailing.addAll(newTrailing);
+                            trailingPadding.addAll(newTrailingPadding);
+                        } else {
+                            newLeading.addAll(newTrailing);
+                            newLeadingPadding.addAll(newTrailingPadding);
+                        }
+                    } else {
+                        // Gap
+                        newLeadingPadding.clear();
+                        newLeading.clear();
+                        counter++;
+                    }
+                }
+            }
+        }
+
+        int getBaseline() {
+            if (baselineSpring != null) {
+                int baseline = baselineSpring.getBaseline();
+                if (baseline >= 0) {
+                    int size = 0;
+                    for (Spring spring : springs) {
+                        if (spring == baselineSpring) {
+                            return size + baseline;
+                        } else {
+                            size += spring.getPreferredSize(VERTICAL);
+                        }
+                    }
+                }
+            }
+            return -1;
+        }
+
+        BaselineResizeBehavior getBaselineResizeBehavior() {
+            if (isResizable(VERTICAL)) {
+                if (!baselineSpring.isResizable(VERTICAL)) {
+                    // Spring to use for baseline isn't resizable. In this case
+                    // baseline resize behavior can be determined based on how
+                    // preceeding springs resize.
+                    boolean leadingResizable = false;
+                    for (Spring spring : springs) {
+                        if (spring == baselineSpring) {
+                            break;
+                        } else if (spring.isResizable(VERTICAL)) {
+                            leadingResizable = true;
+                            break;
+                        }
+                    }
+                    boolean trailingResizable = false;
+                    for (int i = springs.size() - 1; i >= 0; i--) {
+                        Spring spring = springs.get(i);
+                        if (spring == baselineSpring) {
+                            break;
+                        }
+                        if (spring.isResizable(VERTICAL)) {
+                            trailingResizable = true;
+                            break;
+                        }
+                    }
+                    if (leadingResizable && !trailingResizable) {
+                        return BaselineResizeBehavior.CONSTANT_DESCENT;
+                    } else if (!leadingResizable && trailingResizable) {
+                        return BaselineResizeBehavior.CONSTANT_ASCENT;
+                    }
+                    // If we get here, both leading and trailing springs are
+                    // resizable. Fall through to OTHER.
+                } else {
+                    BaselineResizeBehavior brb = baselineSpring.getBaselineResizeBehavior();
+                    if (brb == BaselineResizeBehavior.CONSTANT_ASCENT) {
+                        for (Spring spring : springs) {
+                            if (spring == baselineSpring) {
+                                return BaselineResizeBehavior.CONSTANT_ASCENT;
+                            }
+                            if (spring.isResizable(VERTICAL)) {
+                                return BaselineResizeBehavior.OTHER;
+                            }
+                        }
+                    } else if (brb == BaselineResizeBehavior.CONSTANT_DESCENT) {
+                        for (int i = springs.size() - 1; i >= 0; i--) {
+                            Spring spring = springs.get(i);
+                            if (spring == baselineSpring) {
+                                return BaselineResizeBehavior.CONSTANT_DESCENT;
+                            }
+                            if (spring.isResizable(VERTICAL)) {
+                                return BaselineResizeBehavior.OTHER;
+                            }
+                        }
+                    }
+                }
+                return BaselineResizeBehavior.OTHER;
+            }
+            // Not resizable, treat as constant_ascent
+            return BaselineResizeBehavior.CONSTANT_ASCENT;
+        }
+
+        private void checkPreferredGapValues(int pref, int max) {
+            if ((pref < 0 && pref != DEFAULT_SIZE && pref != PREFERRED_SIZE) ||
+                    (max < 0 && max != DEFAULT_SIZE && max != PREFERRED_SIZE)||
+                    (pref >= 0 && max >= 0 && pref > max)) {
+                throw new IllegalArgumentException(
+                        "Pref and max must be either DEFAULT_SIZE, " +
+                        "PREFERRED_SIZE, or >= 0 and pref <= max");
+            }
+        }
+    }
+
+
+    /**
+     * Used by SequentialGroup in calculating resizability of springs.
+     */
+    private static final class SpringDelta implements Comparable<SpringDelta> {
+        // Original index.
+        public final int index;
+        // Delta, one of pref - min or max - pref.
+        public int delta;
+
+        public SpringDelta(int index, int delta) {
+            this.index = index;
+            this.delta = delta;
+        }
+
+        public int compareTo(SpringDelta o) {
+            return delta - o.delta;
+        }
+
+        public String toString() {
+            return super.toString() + "[index=" + index + ", delta=" +
+                    delta + "]";
+        }
+    }
+
+
+    /**
+     * A {@code Group} that aligns and sizes it's children.
+     * {@code ParallelGroup} aligns it's children in
+     * four possible ways: along the baseline, centered, anchored to the
+     * leading edge, or anchored to the trailing edge.
+     * <h3>Baseline</h3>
+     * A {@code ParallelGroup} that aligns it's children along the
+     * baseline must first decide where the baseline is
+     * anchored. The baseline can either be anchored to the top, or
+     * anchored to the bottom of the group. That is, the distance between the
+     * baseline and the beginning of the group can be a constant
+     * distance, or the distance between the end of the group and the
+     * baseline can be a constant distance. The possible choices
+     * correspond to the {@code BaselineResizeBehavior} constants
+     * {@link
+     * java.awt.Component.BaselineResizeBehavior#CONSTANT_ASCENT CONSTANT_ASCENT} and
+     * {@link
+     * java.awt.Component.BaselineResizeBehavior#CONSTANT_DESCENT CONSTANT_DESCENT}.
+     * <p>
+     * The baseline anchor may be explicitly specified by the
+     * {@code createBaselineGroup} method, or determined based on the elements.
+     * If not explicitly specified, the baseline will be anchored to
+     * the bottom if all the elements with a baseline, and that are
+     * aligned to the baseline, have a baseline resize behavior of
+     * {@code CONSTANT_DESCENT}; otherwise the baseline is anchored to the top
+     * of the group.
+     * <p>
+     * Elements aligned to the baseline are resizable if they have have
+     * a baseline resize behavior of {@code CONSTANT_ASCENT} or
+     * {@code CONSTANT_DESCENT}. Elements with a baseline resize
+     * behavior of {@code OTHER} or {@code CENTER_OFFSET} are not resizable.
+     * <p>
+     * The baseline is calculated based on the preferred height of each
+     * of the elements that have a baseline. The baseline is
+     * calculated using the following algorithm:
+     * {@code max(maxNonBaselineHeight, maxAscent + maxDescent)}, where the
+     * {@code maxNonBaselineHeight} is the maximum height of all elements
+     * that do not have a baseline, or are not aligned along the baseline.
+     * {@code maxAscent} is the maximum ascent (baseline) of all elements that
+     * have a baseline and are aligned along the baseline.
+     * {@code maxDescent} is the maximum descent (preferred height - baseline)
+     * of all elements that have a baseline and are aligned along the baseline.
+     * <p>
+     * A {@code ParallelGroup} that aligns it's elements along the baseline
+     * is only useful along the vertical axis. If you create a
+     * baseline group and use it along the horizontal axis an
+     * {@code IllegalStateException} is thrown when you ask
+     * {@code GroupLayout} for the minimum, preferred or maximum size or
+     * attempt to layout the components.
+     * <p>
+     * Elements that are not aligned to the baseline and smaller than the size
+     * of the {@code ParallelGroup} are positioned in one of three
+     * ways: centered, anchored to the leading edge, or anchored to the
+     * trailing edge.
+     *
+     * <h3>Non-baseline {@code ParallelGroup}</h3>
+     * {@code ParallelGroup}s created with an alignment other than
+     * {@code BASELINE} align elements that are smaller than the size
+     * of the group in one of three ways: centered, anchored to the
+     * leading edge, or anchored to the trailing edge.
+     * <p>
+     * The leading edge is based on the axis and {@code
+     * ComponentOrientation}.  For the vertical axis the top edge is
+     * always the leading edge, and the bottom edge is always the
+     * trailing edge. When the {@code ComponentOrientation} is {@code
+     * LEFT_TO_RIGHT}, the leading edge is the left edge and the
+     * trailing edge the right edge. A {@code ComponentOrientation} of
+     * {@code RIGHT_TO_LEFT} flips the left and right edges. Child
+     * elements are aligned based on the specified alignment the
+     * element was added with. If you do not specify an alignment, the
+     * alignment specified for the {@code ParallelGroup} is used.
+     * <p>
+     * To align elements along the baseline you {@code createBaselineGroup},
+     * or {@code createParallelGroup} with an alignment of {@code BASELINE}.
+     * If the group was not created with a baseline alignment, and you attempt
+     * to add an element specifying a baseline alignment, an
+     * {@code IllegalArgumentException} is thrown.
+     *
+     * @see #createParallelGroup()
+     * @see #createBaselineGroup(boolean,boolean)
+     * @since 1.6
+     */
+    public class ParallelGroup extends Group {
+        // How children are layed out.
+        private final Alignment childAlignment;
+        // Whether or not we're resizable.
+        private final boolean resizable;
+
+        ParallelGroup(Alignment childAlignment, boolean resizable) {
+            this.childAlignment = childAlignment;
+            this.resizable = resizable;
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public ParallelGroup addGroup(Group group) {
+            return (ParallelGroup)super.addGroup(group);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public ParallelGroup addComponent(Component component) {
+            return (ParallelGroup)super.addComponent(component);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public ParallelGroup addComponent(Component component, int min, int pref,
+                int max) {
+            return (ParallelGroup)super.addComponent(component, min, pref, max);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public ParallelGroup addGap(int pref) {
+            return (ParallelGroup)super.addGap(pref);
+        }
+
+        /**
+         * {@inheritDoc}
+         */
+        public ParallelGroup addGap(int min, int pref, int max) {
+            return (ParallelGroup)super.addGap(min, pref, max);
+        }
+
+        /**
+         * Adds a {@code Group} to this {@code ParallelGroup} with the
+         * specified alignment. If the child is smaller than the
+         * {@code Group} it is aligned based on the specified
+         * alignment.
+         *
+         * @param alignment the alignment
+         * @param group the {@code Group} to add
+         * @return this {@code ParallelGroup}
+         * @throws IllegalArgumentException if {@code alignment} is
+         *         {@code null}
+         */
+        public ParallelGroup addGroup(Alignment alignment, Group group) {
+            checkChildAlignment(alignment);
+            group.setAlignment(alignment);
+            return (ParallelGroup)addSpring(group);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code ParallelGroup} with
+         * the specified alignment.
+         *
+         * @param alignment the alignment
+         * @param component the {@code Component} to add
+         * @return this {@code Group}
+         * @throws IllegalArgumentException if {@code alignment} is
+         *         {@code null}
+         */
+        public ParallelGroup addComponent(Component component,
+                Alignment alignment) {
+            return addComponent(component, alignment, DEFAULT_SIZE, DEFAULT_SIZE,
+                    DEFAULT_SIZE);
+        }
+
+        /**
+         * Adds a {@code Component} to this {@code ParallelGroup} with the
+         * specified alignment and size.
+         *
+         * @param alignment the alignment
+         * @param component the {@code Component} to add
+         * @param min the minimum size
+         * @param pref the preferred size
+         * @param max the maximum size
+         * @throws IllegalArgumentException if {@code alignment} is
+         *         {@code null}
+         * @return this {@code Group}
+         */
+        public ParallelGroup addComponent(Component component,
+                Alignment alignment, int min, int pref, int max) {
+            checkChildAlignment(alignment);
+            ComponentSpring spring = new ComponentSpring(component,
+                    min, pref, max);
+            spring.setAlignment(alignment);
+            return (ParallelGroup)addSpring(spring);
+        }
+
+        boolean isResizable() {
+            return resizable;
+        }
+
+        int operator(int a, int b) {
+            return Math.max(a, b);
+        }
+
+        int calculateMinimumSize(int axis) {
+            if (!isResizable()) {
+                return getPreferredSize(axis);
+            }
+            return super.calculateMinimumSize(axis);
+        }
+
+        int calculateMaximumSize(int axis) {
+            if (!isResizable()) {
+                return getPreferredSize(axis);
+            }
+            return super.calculateMaximumSize(axis);
+        }
+
+        void setValidSize(int axis, int origin, int size) {
+            for (Spring spring : springs) {
+                setChildSize(spring, axis, origin, size);
+            }
+        }
+
+        void setChildSize(Spring spring, int axis, int origin, int size) {
+            Alignment alignment = spring.getAlignment();
+            int springSize = Math.min(
+                    Math.max(spring.getMinimumSize(axis), size),
+                    spring.getMaximumSize(axis));
+            if (alignment == null) {
+                alignment = childAlignment;
+            }
+            switch (alignment) {
+                case TRAILING:
+                    spring.setSize(axis, origin + size - springSize,
+                            springSize);
+                    break;
+                case CENTER:
+                    spring.setSize(axis, origin +
+                            (size - springSize) / 2,springSize);
+                    break;
+                default: // LEADING, or BASELINE
+                    spring.setSize(axis, origin, springSize);
+                    break;
+            }
+        }
+
+        @Override
+        void insertAutopadding(int axis,
+                List<AutoPreferredGapSpring> leadingPadding,
+                List<AutoPreferredGapSpring> trailingPadding,
+                List<ComponentSpring> leading, List<ComponentSpring> trailing,
+                boolean insert) {
+            for (Spring spring : springs) {
+                if (spring instanceof ComponentSpring) {
+                    if (((ComponentSpring)spring).isVisible()) {
+                        for (AutoPreferredGapSpring gapSpring :
+                                 leadingPadding) {
+                            gapSpring.addTarget((ComponentSpring)spring, axis);
+                        }
+                        trailing.add((ComponentSpring)spring);
+                    }
+                } else if (spring instanceof Group) {
+                    ((Group)spring).insertAutopadding(axis, leadingPadding,
+                            trailingPadding, leading, trailing, insert);
+                } else if (spring instanceof AutoPreferredGapSpring) {
+                    ((AutoPreferredGapSpring)spring).setSources(leading);
+                    trailingPadding.add((AutoPreferredGapSpring)spring);
+                }
+            }
+        }
+
+        private void checkChildAlignment(Alignment alignment) {
+            checkChildAlignment(alignment, (this instanceof BaselineGroup));
+        }
+
+        private void checkChildAlignment(Alignment alignment,
+                boolean allowsBaseline) {
+            if (alignment == null) {
+                throw new IllegalArgumentException("Alignment must be non-null");
+            }
+            if (!allowsBaseline && alignment == Alignment.BASELINE) {
+                throw new IllegalArgumentException("Alignment must be one of:" +
+                        "LEADING, TRAILING or CENTER");
+            }
+        }
+    }
+
+
+    /**
+     * An extension of {@code ParallelGroup} that aligns its
+     * constituent {@code Spring}s along the baseline.
+     */
+    private class BaselineGroup extends ParallelGroup {
+        // Whether or not all child springs have a baseline
+        private boolean allSpringsHaveBaseline;
+
+        // max(spring.getBaseline()) of all springs aligned along the baseline
+        // that have a baseline
+        private int prefAscent;
+
+        // max(spring.getPreferredSize().height - spring.getBaseline()) of all
+        // springs aligned along the baseline that have a baseline
+        private int prefDescent;
+
+        // Whether baselineAnchoredToTop was explicitly set
+        private boolean baselineAnchorSet;
+
+        // Whether the baseline is anchored to the top or the bottom.
+        // If anchored to the top the baseline is always at prefAscent,
+        // otherwise the baseline is at (height - prefDescent)
+        private boolean baselineAnchoredToTop;
+
+        // Whether or not the baseline has been calculated.
+        private boolean calcedBaseline;
+
+        BaselineGroup(boolean resizable) {
+            super(Alignment.LEADING, resizable);
+            prefAscent = prefDescent = -1;
+            calcedBaseline = false;
+        }
+
+        BaselineGroup(boolean resizable, boolean baselineAnchoredToTop) {
+            this(resizable);
+            this.baselineAnchoredToTop = baselineAnchoredToTop;
+            baselineAnchorSet = true;
+        }
+
+        void unset() {
+            super.unset();
+            prefAscent = prefDescent = -1;
+            calcedBaseline = false;
+        }
+
+        void setValidSize(int axis, int origin, int size) {
+            checkAxis(axis);
+            if (prefAscent == -1) {
+                super.setValidSize(axis, origin, size);
+            } else {
+                // do baseline layout
+                baselineLayout(origin, size);
+            }
+        }
+
+        int calculateSize(int axis, int type) {
+            checkAxis(axis);
+            if (!calcedBaseline) {
+                calculateBaselineAndResizeBehavior();
+            }
+            if (type == MIN_SIZE) {
+                return calculateMinSize();
+            }
+            if (type == MAX_SIZE) {
+                return calculateMaxSize();
+            }
+            if (allSpringsHaveBaseline) {
+                return prefAscent + prefDescent;
+            }
+            return Math.max(prefAscent + prefDescent,
+                    super.calculateSize(axis, type));
+        }
+
+        private void calculateBaselineAndResizeBehavior() {
+            // calculate baseline
+            prefAscent = 0;
+            prefDescent = 0;
+            int baselineSpringCount = 0;
+            BaselineResizeBehavior resizeBehavior = null;
+            for (Spring spring : springs) {
+                if (spring.getAlignment() == null ||
+                        spring.getAlignment() == Alignment.BASELINE) {
+                    int baseline = spring.getBaseline();
+                    if (baseline >= 0) {
+                        if (spring.isResizable(VERTICAL)) {
+                            BaselineResizeBehavior brb = spring.
+                                    getBaselineResizeBehavior();
+                            if (resizeBehavior == null) {
+                                resizeBehavior = brb;
+                            } else if (brb != resizeBehavior) {
+                                resizeBehavior = BaselineResizeBehavior.
+                                        CONSTANT_ASCENT;
+                            }
+                        }
+                        prefAscent = Math.max(prefAscent, baseline);
+                        prefDescent = Math.max(prefDescent, spring.
+                                getPreferredSize(VERTICAL) - baseline);
+                        baselineSpringCount++;
+                    }
+                }
+            }
+            if (!baselineAnchorSet) {
+                if (resizeBehavior == BaselineResizeBehavior.CONSTANT_DESCENT){
+                    this.baselineAnchoredToTop = false;
+                } else {
+                    this.baselineAnchoredToTop = true;
+                }
+            }
+            allSpringsHaveBaseline = (baselineSpringCount == springs.size());
+            calcedBaseline = true;
+        }
+
+        private int calculateMaxSize() {
+            int maxAscent = prefAscent;
+            int maxDescent = prefDescent;
+            int nonBaselineMax = 0;
+            for (Spring spring : springs) {
+                int baseline;
+                int springMax = spring.getMaximumSize(VERTICAL);
+                if ((spring.getAlignment() == null ||
+                        spring.getAlignment() == Alignment.BASELINE) &&
+                        (baseline = spring.getBaseline()) >= 0) {
+                    int springPref = spring.getPreferredSize(VERTICAL);
+                    if (springPref != springMax) {
+                        switch (spring.getBaselineResizeBehavior()) {
+                            case CONSTANT_ASCENT:
+                                if (baselineAnchoredToTop) {
+                                    maxDescent = Math.max(maxDescent,
+                                            springMax - baseline);
+                                }
+                                break;
+                            case CONSTANT_DESCENT:
+                                if (!baselineAnchoredToTop) {
+                                    maxAscent = Math.max(maxAscent,
+                                            springMax - springPref + baseline);
+                                }
+                                break;
+                            default: // CENTER_OFFSET and OTHER, not resizable
+                                break;
+                        }
+                    }
+                } else {
+                    // Not aligned along the baseline, or no baseline.
+                    nonBaselineMax = Math.max(nonBaselineMax, springMax);
+                }
+            }
+            return Math.max(nonBaselineMax, maxAscent + maxDescent);
+        }
+
+        private int calculateMinSize() {
+            int minAscent = 0;
+            int minDescent = 0;
+            int nonBaselineMin = 0;
+            if (baselineAnchoredToTop) {
+                minAscent = prefAscent;
+            } else {
+                minDescent = prefDescent;
+            }
+            for (Spring spring : springs) {
+                int springMin = spring.getMinimumSize(VERTICAL);
+                int baseline;
+                if ((spring.getAlignment() == null ||
+                        spring.getAlignment() == Alignment.BASELINE) &&
+                        (baseline = spring.getBaseline()) >= 0) {
+                    int springPref = spring.getPreferredSize(VERTICAL);
+                    BaselineResizeBehavior brb = spring.
+                            getBaselineResizeBehavior();
+                    switch (brb) {
+                        case CONSTANT_ASCENT:
+                            if (baselineAnchoredToTop) {
+                                minDescent = Math.max(springMin - baseline,
+                                        minDescent);
+                            } else {
+                                minAscent = Math.max(baseline, minAscent);
+                            }
+                            break;
+                        case CONSTANT_DESCENT:
+                            if (!baselineAnchoredToTop) {
+                                minAscent = Math.max(
+                                        baseline - (springPref - springMin),
+                                        minAscent);
+                            } else {
+                                minDescent = Math.max(springPref - baseline,
+                                        minDescent);
+                            }
+                            break;
+                        default:
+                            // CENTER_OFFSET and OTHER are !resizable, use
+                            // the preferred size.
+                            minAscent = Math.max(baseline, minAscent);
+                            minDescent = Math.max(springPref - baseline,
+                                    minDescent);
+                            break;
+                    }
+                } else {
+                    // Not aligned along the baseline, or no baseline.
+                    nonBaselineMin = Math.max(nonBaselineMin, springMin);
+                }
+            }
+            return Math.max(nonBaselineMin, minAscent + minDescent);
+        }
+
+        /**
+         * Lays out springs that have a baseline along the baseline.  All
+         * others are centered.
+         */
+        private void baselineLayout(int origin, int size) {
+            int ascent;
+            int descent;
+            if (baselineAnchoredToTop) {
+                ascent = prefAscent;
+                descent = size - ascent;
+            } else {
+                ascent = size - prefDescent;
+                descent = prefDescent;
+            }
+            for (Spring spring : springs) {
+                Alignment alignment = spring.getAlignment();
+                if (alignment == null || alignment == Alignment.BASELINE) {
+                    int baseline = spring.getBaseline();
+                    if (baseline >= 0) {
+                        int springMax = spring.getMaximumSize(VERTICAL);
+                        int springPref = spring.getPreferredSize(VERTICAL);
+                        int height = springPref;
+                        int y;
+                        switch(spring.getBaselineResizeBehavior()) {
+                            case CONSTANT_ASCENT:
+                                y = origin + ascent - baseline;
+                                height = Math.min(descent, springMax -
+                                        baseline) + baseline;
+                                break;
+                            case CONSTANT_DESCENT:
+                                height = Math.min(ascent, springMax -
+                                        springPref + baseline) +
+                                        (springPref - baseline);
+                                y = origin + ascent +
+                                        (springPref - baseline) - height;
+                                break;
+                            default: // CENTER_OFFSET & OTHER, not resizable
+                                y = origin + ascent - baseline;
+                                break;
+                        }
+                        spring.setSize(VERTICAL, y, height);
+                    } else {
+                        setChildSize(spring, VERTICAL, origin, size);
+                    }
+                } else {
+                    setChildSize(spring, VERTICAL, origin, size);
+                }
+            }
+        }
+
+        int getBaseline() {
+            if (springs.size() > 1) {
+                // Force the baseline to be calculated
+                getPreferredSize(VERTICAL);
+                return prefAscent;
+            } else if (springs.size() == 1) {
+                return springs.get(0).getBaseline();
+            }
+            return -1;
+        }
+
+        BaselineResizeBehavior getBaselineResizeBehavior() {
+            if (springs.size() == 1) {
+                return springs.get(0).getBaselineResizeBehavior();
+            }
+            if (baselineAnchoredToTop) {
+                return BaselineResizeBehavior.CONSTANT_ASCENT;
+            }
+            return BaselineResizeBehavior.CONSTANT_DESCENT;
+        }
+
+        // If the axis is VERTICAL, throws an IllegalStateException
+        private void checkAxis(int axis) {
+            if (axis == HORIZONTAL) {
+                throw new IllegalStateException(
+                        "Baseline must be used along vertical axis");
+            }
+        }
+    }
+
+
+    private final class ComponentSpring extends Spring {
+        private Component component;
+        private int origin;
+
+        // min/pref/max are either a value >= 0 or one of
+        // DEFAULT_SIZE or PREFERRED_SIZE
+        private final int min;
+        private final int pref;
+        private final int max;
+
+        // Baseline for the component, computed as necessary.
+        private int baseline = -1;
+
+        // Whether or not the size has been requested yet.
+        private boolean installed;
+
+        private ComponentSpring(Component component, int min, int pref,
+                int max) {
+            this.component = component;
+            if (component == null) {
+                throw new IllegalArgumentException(
+                        "Component must be non-null");
+            }
+
+            checkSize(min, pref, max, true);
+
+            this.min = min;
+            this.max = max;
+            this.pref = pref;
+
+            // getComponentInfo makes sure component is a child of the
+            // Container GroupLayout is the LayoutManager for.
+            getComponentInfo(component);
+        }
+
+        int calculateMinimumSize(int axis) {
+            if (isLinked(axis)) {
+                return getLinkSize(axis, MIN_SIZE);
+            }
+            return calculateNonlinkedMinimumSize(axis);
+        }
+
+        int calculatePreferredSize(int axis) {
+            if (isLinked(axis)) {
+                return getLinkSize(axis, PREF_SIZE);
+            }
+            int min = getMinimumSize(axis);
+            int pref = calculateNonlinkedPreferredSize(axis);
+            int max = getMaximumSize(axis);
+            return Math.min(max, Math.max(min, pref));
+        }
+
+        int calculateMaximumSize(int axis) {
+            if (isLinked(axis)) {
+                return getLinkSize(axis, MAX_SIZE);
+            }
+            return Math.max(getMinimumSize(axis),
+                    calculateNonlinkedMaximumSize(axis));
+        }
+
+        boolean isVisible() {
+            return getComponentInfo(getComponent()).isVisible();
+        }
+
+        int calculateNonlinkedMinimumSize(int axis) {
+            if (!isVisible()) {
+                return 0;
+            }
+            if (min >= 0) {
+                return min;
+            }
+            if (min == PREFERRED_SIZE) {
+                return calculateNonlinkedPreferredSize(axis);
+            }
+            assert (min == DEFAULT_SIZE);
+            return getSizeAlongAxis(axis, component.getMinimumSize());
+        }
+
+        int calculateNonlinkedPreferredSize(int axis) {
+            if (!isVisible()) {
+                return 0;
+            }
+            if (pref >= 0) {
+                return pref;
+            }
+            assert (pref == DEFAULT_SIZE || pref == PREFERRED_SIZE);
+            return getSizeAlongAxis(axis, component.getPreferredSize());
+        }
+
+        int calculateNonlinkedMaximumSize(int axis) {
+            if (!isVisible()) {
+                return 0;
+            }
+            if (max >= 0) {
+                return max;
+            }
+            if (max == PREFERRED_SIZE) {
+                return calculateNonlinkedPreferredSize(axis);
+            }
+            assert (max == DEFAULT_SIZE);
+            return getSizeAlongAxis(axis, component.getMaximumSize());
+        }
+
+        private int getSizeAlongAxis(int axis, Dimension size) {
+            return (axis == HORIZONTAL) ? size.width : size.height;
+        }
+
+        private int getLinkSize(int axis, int type) {
+            if (!isVisible()) {
+                return 0;
+            }
+            ComponentInfo ci = getComponentInfo(component);
+            return ci.getLinkSize(axis, type);
+        }
+
+        void setSize(int axis, int origin, int size) {
+            super.setSize(axis, origin, size);
+            this.origin = origin;
+            if (size == UNSET) {
+                baseline = -1;
+            }
+        }
+
+        int getOrigin() {
+            return origin;
+        }
+
+        void setComponent(Component component) {
+            this.component = component;
+        }
+
+        Component getComponent() {
+            return component;
+        }
+
+        int getBaseline() {
+            if (baseline == -1) {
+                Spring horizontalSpring = getComponentInfo(component).
+                        horizontalSpring;
+                int width = horizontalSpring.getPreferredSize(HORIZONTAL);
+                int height = getPreferredSize(VERTICAL);
+                if (width > 0 && height > 0) {
+                    baseline = component.getBaseline(width, height);
+                }
+            }
+            return baseline;
+        }
+
+        BaselineResizeBehavior getBaselineResizeBehavior() {
+            return getComponent().getBaselineResizeBehavior();
+        }
+
+        private boolean isLinked(int axis) {
+            return getComponentInfo(component).isLinked(axis);
+        }
+
+        void installIfNecessary(int axis) {
+            if (!installed) {
+                installed = true;
+                if (axis == HORIZONTAL) {
+                    getComponentInfo(component).horizontalSpring = this;
+                } else {
+                    getComponentInfo(component).verticalSpring = this;
+                }
+            }
+        }
+
+        @Override
+        boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized) {
+            return !isVisible();
+        }
+    }
+
+
+    /**
+     * Spring representing the preferred distance between two components.
+     */
+    private class PreferredGapSpring extends Spring {
+        private final JComponent source;
+        private final JComponent target;
+        private final ComponentPlacement type;
+        private final int pref;
+        private final int max;
+
+        PreferredGapSpring(JComponent source, JComponent target,
+                ComponentPlacement type, int pref, int max) {
+            this.source = source;
+            this.target = target;
+            this.type = type;
+            this.pref = pref;
+            this.max = max;
+        }
+
+        int calculateMinimumSize(int axis) {
+            return getPadding(axis);
+        }
+
+        int calculatePreferredSize(int axis) {
+            if (pref == DEFAULT_SIZE || pref == PREFERRED_SIZE) {
+                return getMinimumSize(axis);
+            }
+            int min = getMinimumSize(axis);
+            int max = getMaximumSize(axis);
+            return Math.min(max, Math.max(min, pref));
+        }
+
+        int calculateMaximumSize(int axis) {
+            if (max == PREFERRED_SIZE || max == DEFAULT_SIZE) {
+                return getPadding(axis);
+            }
+            return Math.max(getMinimumSize(axis), max);
+        }
+
+        private int getPadding(int axis) {
+            int position;
+            if (axis == HORIZONTAL) {
+                position = SwingConstants.EAST;
+            } else {
+                position = SwingConstants.SOUTH;
+            }
+            return getLayoutStyle0().getPreferredGap(source,
+                    target, type, position, host);
+        }
+
+        @Override
+        boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized) {
+            return false;
+        }
+    }
+
+
+    /**
+     * Spring represented a certain amount of space.
+     */
+    private class GapSpring extends Spring {
+        private final int min;
+        private final int pref;
+        private final int max;
+
+        GapSpring(int min, int pref, int max) {
+            checkSize(min, pref, max, false);
+            this.min = min;
+            this.pref = pref;
+            this.max = max;
+        }
+
+        int calculateMinimumSize(int axis) {
+            if (min == PREFERRED_SIZE) {
+                return getPreferredSize(axis);
+            }
+            return min;
+        }
+
+        int calculatePreferredSize(int axis) {
+            return pref;
+        }
+
+        int calculateMaximumSize(int axis) {
+            if (max == PREFERRED_SIZE) {
+                return getPreferredSize(axis);
+            }
+            return max;
+        }
+
+        @Override
+        boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized) {
+            return false;
+        }
+    }
+
+
+    /**
+     * Spring reprensenting the distance between any number of sources and
+     * targets.  The targets and sources are computed during layout.  An
+     * instance of this can either be dynamically created when
+     * autocreatePadding is true, or explicitly created by the developer.
+     */
+    private class AutoPreferredGapSpring extends Spring {
+        List<ComponentSpring> sources;
+        ComponentSpring source;
+        private List<AutoPreferredGapMatch> matches;
+        int size;
+        int lastSize;
+        private final int pref;
+        private final int max;
+        // Type of gap
+        private ComponentPlacement type;
+        private boolean userCreated;
+
+        private AutoPreferredGapSpring() {
+            this.pref = PREFERRED_SIZE;
+            this.max = PREFERRED_SIZE;
+            this.type = ComponentPlacement.RELATED;
+        }
+
+        AutoPreferredGapSpring(int pref, int max) {
+            this.pref = pref;
+            this.max = max;
+        }
+
+        AutoPreferredGapSpring(ComponentPlacement type, int pref, int max) {
+            this.type = type;
+            this.pref = pref;
+            this.max = max;
+            this.userCreated = true;
+        }
+
+        public void setSource(ComponentSpring source) {
+            this.source = source;
+        }
+
+        public void setSources(List<ComponentSpring> sources) {
+            this.sources = new ArrayList<ComponentSpring>(sources);
+        }
+
+        public void setUserCreated(boolean userCreated) {
+            this.userCreated = userCreated;
+        }
+
+        public boolean getUserCreated() {
+            return userCreated;
+        }
+
+        void unset() {
+            lastSize = getSize();
+            super.unset();
+            size = 0;
+        }
+
+        public void reset() {
+            size = 0;
+            sources = null;
+            source = null;
+            matches = null;
+        }
+
+        public void calculatePadding(int axis) {
+            size = UNSET;
+            int maxPadding = UNSET;
+            if (matches != null) {
+                LayoutStyle p = getLayoutStyle0();
+                int position;
+                if (axis == HORIZONTAL) {
+                    if (isLeftToRight()) {
+                        position = SwingConstants.EAST;
+                    } else {
+                        position = SwingConstants.WEST;
+                    }
+                } else {
+                    position = SwingConstants.SOUTH;
+                }
+                for (int i = matches.size() - 1; i >= 0; i--) {
+                    AutoPreferredGapMatch match = matches.get(i);
+                    maxPadding = Math.max(maxPadding,
+                            calculatePadding(p, position, match.source,
+                            match.target));
+                }
+            }
+            if (size == UNSET) {
+                size = 0;
+            }
+            if (maxPadding == UNSET) {
+                maxPadding = 0;
+            }
+            if (lastSize != UNSET) {
+                size += Math.min(maxPadding, lastSize);
+            }
+        }
+
+        private int calculatePadding(LayoutStyle p, int position,
+                ComponentSpring source,
+                ComponentSpring target) {
+            int delta = target.getOrigin() - (source.getOrigin() +
+                    source.getSize());
+            if (delta >= 0) {
+                int padding;
+                if ((source.getComponent() instanceof JComponent) &&
+                        (target.getComponent() instanceof JComponent)) {
+                    padding = p.getPreferredGap(
+                            (JComponent)source.getComponent(),
+                            (JComponent)target.getComponent(), type, position,
+                            host);
+                } else {
+                    padding = 10;
+                }
+                if (padding > delta) {
+                    size = Math.max(size, padding - delta);
+                }
+                return padding;
+            }
+            return 0;
+        }
+
+        public void addTarget(ComponentSpring spring, int axis) {
+            int oAxis = (axis == HORIZONTAL) ? VERTICAL : HORIZONTAL;
+            if (source != null) {
+                if (areParallelSiblings(source.getComponent(),
+                        spring.getComponent(), oAxis)) {
+                    addValidTarget(source, spring);
+                }
+            } else {
+                Component component = spring.getComponent();
+                for (int counter = sources.size() - 1; counter >= 0;
+                         counter--){
+                    ComponentSpring source = sources.get(counter);
+                    if (areParallelSiblings(source.getComponent(),
+                            component, oAxis)) {
+                        addValidTarget(source, spring);
+                    }
+                }
+            }
+        }
+
+        private void addValidTarget(ComponentSpring source,
+                ComponentSpring target) {
+            if (matches == null) {
+                matches = new ArrayList<AutoPreferredGapMatch>(1);
+            }
+            matches.add(new AutoPreferredGapMatch(source, target));
+        }
+
+        int calculateMinimumSize(int axis) {
+            return size;
+        }
+
+        int calculatePreferredSize(int axis) {
+            if (pref == PREFERRED_SIZE || pref == DEFAULT_SIZE) {
+                return size;
+            }
+            return Math.max(size, pref);
+        }
+
+        int calculateMaximumSize(int axis) {
+            if (max >= 0) {
+                return Math.max(getPreferredSize(axis), max);
+            }
+            return size;
+        }
+
+        String getMatchDescription() {
+            return (matches == null) ? "" : matches.toString();
+        }
+
+        public String toString() {
+            return super.toString() + getMatchDescription();
+        }
+
+        @Override
+        boolean willHaveZeroSize(boolean treatAutopaddingAsZeroSized) {
+            return treatAutopaddingAsZeroSized;
+        }
+    }
+
+
+    /**
+     * Represents two springs that should have autopadding inserted between
+     * them.
+     */
+    private final static class AutoPreferredGapMatch {
+        public final ComponentSpring source;
+        public final ComponentSpring target;
+
+        AutoPreferredGapMatch(ComponentSpring source, ComponentSpring target) {
+            this.source = source;
+            this.target = target;
+        }
+
+        private String toString(ComponentSpring spring) {
+            return spring.getComponent().getName();
+        }
+
+        public String toString() {
+            return "[" + toString(source) + "-" + toString(target) + "]";
+        }
+    }
+
+
+    /**
+     * An extension of AutopaddingSpring used for container level padding.
+     */
+    private class ContainerAutoPreferredGapSpring extends
+            AutoPreferredGapSpring {
+        private List<ComponentSpring> targets;
+
+        ContainerAutoPreferredGapSpring() {
+            super();
+            setUserCreated(true);
+        }
+
+        ContainerAutoPreferredGapSpring(int pref, int max) {
+            super(pref, max);
+            setUserCreated(true);
+        }
+
+        public void addTarget(ComponentSpring spring, int axis) {
+            if (targets == null) {
+                targets = new ArrayList<ComponentSpring>(1);
+            }
+            targets.add(spring);
+        }
+
+        public void calculatePadding(int axis) {
+            LayoutStyle p = getLayoutStyle0();
+            int maxPadding = 0;
+            int position;
+            size = 0;
+            if (targets != null) {
+                // Leading
+                if (axis == HORIZONTAL) {
+                    if (isLeftToRight()) {
+                        position = SwingConstants.WEST;
+                    } else {
+                        position = SwingConstants.EAST;
+                    }
+                } else {
+                    position = SwingConstants.SOUTH;
+                }
+                for (int i = targets.size() - 1; i >= 0; i--) {
+                    ComponentSpring targetSpring = targets.get(i);
+                    int padding = 10;
+                    if (targetSpring.getComponent() instanceof JComponent) {
+                        padding = p.getContainerGap(
+                                (JComponent)targetSpring.getComponent(),
+                                position, host);
+                        maxPadding = Math.max(padding, maxPadding);
+                        padding -= targetSpring.getOrigin();
+                    } else {
+                        maxPadding = Math.max(padding, maxPadding);
+                    }
+                    size = Math.max(size, padding);
+                }
+            } else {
+                // Trailing
+                if (axis == HORIZONTAL) {
+                    if (isLeftToRight()) {
+                        position = SwingConstants.EAST;
+                    } else {
+                        position = SwingConstants.WEST;
+                    }
+                } else {
+                    position = SwingConstants.SOUTH;
+                }
+                if (sources != null) {
+                    for (int i = sources.size() - 1; i >= 0; i--) {
+                        ComponentSpring sourceSpring = sources.get(i);
+                        maxPadding = Math.max(maxPadding,
+                                updateSize(p, sourceSpring, position));
+                    }
+                } else if (source != null) {
+                    maxPadding = updateSize(p, source, position);
+                }
+            }
+            if (lastSize != UNSET) {
+                size += Math.min(maxPadding, lastSize);
+            }
+        }
+
+        private int updateSize(LayoutStyle p, ComponentSpring sourceSpring,
+                int position) {
+            int padding = 10;
+            if (sourceSpring.getComponent() instanceof JComponent) {
+                padding = p.getContainerGap(
+                        (JComponent)sourceSpring.getComponent(), position,
+                        host);
+            }
+            int delta = Math.max(0, getParent().getSize() -
+                    sourceSpring.getSize() - sourceSpring.getOrigin());
+            size = Math.max(size, padding - delta);
+            return padding;
+        }
+
+        String getMatchDescription() {
+            if (targets != null) {
+                return "leading: " + targets.toString();
+            }
+            if (sources != null) {
+                return "trailing: " + sources.toString();
+            }
+            return "--";
+        }
+    }
+
+
+    // LinkInfo contains the set of ComponentInfosthat are linked along a
+    // particular axis.
+    private static class LinkInfo {
+        private final int axis;
+        private final List<ComponentInfo> linked;
+        private int size;
+
+        LinkInfo(int axis) {
+            linked = new ArrayList<ComponentInfo>();
+            size = UNSET;
+            this.axis = axis;
+        }
+
+        public void add(ComponentInfo child) {
+            LinkInfo childMaster = child.getLinkInfo(axis, false);
+            if (childMaster == null) {
+                linked.add(child);
+                child.setLinkInfo(axis, this);
+            } else if (childMaster != this) {
+                linked.addAll(childMaster.linked);
+                for (ComponentInfo childInfo : childMaster.linked) {
+                    childInfo.setLinkInfo(axis, this);
+                }
+            }
+            clearCachedSize();
+        }
+
+        public void remove(ComponentInfo info) {
+            linked.remove(info);
+            info.setLinkInfo(axis, null);
+            if (linked.size() == 1) {
+                linked.get(0).setLinkInfo(axis, null);
+            }
+            clearCachedSize();
+        }
+
+        public void clearCachedSize() {
+            size = UNSET;
+        }
+
+        public int getSize(int axis) {
+            if (size == UNSET) {
+                size = calculateLinkedSize(axis);
+            }
+            return size;
+        }
+
+        private int calculateLinkedSize(int axis) {
+            int size = 0;
+            for (ComponentInfo info : linked) {
+                ComponentSpring spring;
+                if (axis == HORIZONTAL) {
+                    spring = info.horizontalSpring;
+                } else {
+                    assert (axis == VERTICAL);
+                    spring = info.verticalSpring;
+                }
+                size = Math.max(size,
+                        spring.calculateNonlinkedPreferredSize(axis));
+            }
+            return size;
+        }
+    }
+
+    /**
+     * Tracks the horizontal/vertical Springs for a Component.
+     * This class is also used to handle Springs that have their sizes
+     * linked.
+     */
+    private class ComponentInfo {
+        // Component being layed out
+        private Component component;
+
+        ComponentSpring horizontalSpring;
+        ComponentSpring verticalSpring;
+
+        // If the component's size is linked to other components, the
+        // horizontalMaster and/or verticalMaster reference the group of
+        // linked components.
+        private LinkInfo horizontalMaster;
+        private LinkInfo verticalMaster;
+
+        private boolean visible;
+        private Boolean honorsVisibility;
+
+        ComponentInfo(Component component) {
+            this.component = component;
+            updateVisibility();
+        }
+
+        public void dispose() {
+            // Remove horizontal/vertical springs
+            removeSpring(horizontalSpring);
+            horizontalSpring = null;
+            removeSpring(verticalSpring);
+            verticalSpring = null;
+            // Clean up links
+            if (horizontalMaster != null) {
+                horizontalMaster.remove(this);
+            }
+            if (verticalMaster != null) {
+                verticalMaster.remove(this);
+            }
+        }
+
+        void setHonorsVisibility(Boolean honorsVisibility) {
+            this.honorsVisibility = honorsVisibility;
+        }
+
+        private void removeSpring(Spring spring) {
+            if (spring != null) {
+                ((Group)spring.getParent()).springs.remove(spring);
+            }
+        }
+
+        public boolean isVisible() {
+            return visible;
+        }
+
+        /**
+         * Updates the cached visibility.
+         *
+         * @return true if the visibility changed
+         */
+        boolean updateVisibility() {
+            boolean honorsVisibility;
+            if (this.honorsVisibility == null) {
+                honorsVisibility = GroupLayout.this.getHonorsVisibility();
+            } else {
+                honorsVisibility = this.honorsVisibility;
+            }
+            boolean newVisible = (honorsVisibility) ?
+                component.isVisible() : true;
+            if (visible != newVisible) {
+                visible = newVisible;
+                return true;
+            }
+            return false;
+        }
+
+        public void setBounds(Insets insets, int parentWidth, boolean ltr) {
+            int x = horizontalSpring.getOrigin();
+            int w = horizontalSpring.getSize();
+            int y = verticalSpring.getOrigin();
+            int h = verticalSpring.getSize();
+
+            if (!ltr) {
+                x = parentWidth - x - w;
+            }
+            component.setBounds(x + insets.left, y + insets.top, w, h);
+        }
+
+        public void setComponent(Component component) {
+            this.component = component;
+            if (horizontalSpring != null) {
+                horizontalSpring.setComponent(component);
+            }
+            if (verticalSpring != null) {
+                verticalSpring.setComponent(component);
+            }
+        }
+
+        public Component getComponent() {
+            return component;
+        }
+
+        /**
+         * Returns true if this component has its size linked to
+         * other components.
+         */
+        public boolean isLinked(int axis) {
+            if (axis == HORIZONTAL) {
+                return horizontalMaster != null;
+            }
+            assert (axis == VERTICAL);
+            return (verticalMaster != null);
+        }
+
+        private void setLinkInfo(int axis, LinkInfo linkInfo) {
+            if (axis == HORIZONTAL) {
+                horizontalMaster = linkInfo;
+            } else {
+                assert (axis == VERTICAL);
+                verticalMaster = linkInfo;
+            }
+        }
+
+        public LinkInfo getLinkInfo(int axis) {
+            return getLinkInfo(axis, true);
+        }
+
+        private LinkInfo getLinkInfo(int axis, boolean create) {
+            if (axis == HORIZONTAL) {
+                if (horizontalMaster == null && create) {
+                    // horizontalMaster field is directly set by adding
+                    // us to the LinkInfo.
+                    new LinkInfo(HORIZONTAL).add(this);
+                }
+                return horizontalMaster;
+            } else {
+                assert (axis == VERTICAL);
+                if (verticalMaster == null && create) {
+                    // verticalMaster field is directly set by adding
+                    // us to the LinkInfo.
+                    new LinkInfo(VERTICAL).add(this);
+                }
+                return verticalMaster;
+            }
+        }
+
+        public void clearCachedSize() {
+            if (horizontalMaster != null) {
+                horizontalMaster.clearCachedSize();
+            }
+            if (verticalMaster != null) {
+                verticalMaster.clearCachedSize();
+            }
+        }
+
+        int getLinkSize(int axis, int type) {
+            if (axis == HORIZONTAL) {
+                return horizontalMaster.getSize(axis);
+            } else {
+                assert (axis == VERTICAL);
+                return verticalMaster.getSize(axis);
+            }
+        }
+
+    }
+}