/*

 * Copyright 1997-2006 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.util.ArrayList;

import java.util.Hashtable;

import java.awt.Color;

import java.awt.Graphics;

import java.awt.Rectangle;

import javax.accessibility.*;

/**

 * <code>JLayeredPane</code> adds depth to a JFC/Swing container,

 * allowing components to overlap each other when needed.

 * An <code>Integer</code> object specifies each component's depth in the

 * container, where higher-numbered components sit "on top" of other

 * components.

 * For task-oriented documentation and examples of using layered panes see

 * <a href="http://java.sun.com/docs/books/tutorial/uiswing/components/layeredpane.html">How to Use a Layered Pane</a>,

 * a section in <em>The Java Tutorial</em>.

 * <P>

 * <TABLE ALIGN="RIGHT" BORDER="0" SUMMARY="layout">

 * <TR>

 *   <TD ALIGN="CENTER">

 *     <P ALIGN="CENTER"><IMG SRC="doc-files/JLayeredPane-1.gif"

 *     alt="The following text describes this image."

 *     WIDTH="269" HEIGHT="264" ALIGN="BOTTOM" BORDER="0">

 *   </TD>

 * </TR>

 * </TABLE>

 * For convenience, <code>JLayeredPane</code> divides the depth-range

 * into several different layers. Putting a component into one of those

 * layers makes it easy to ensure that components overlap properly,

 * without having to worry about specifying numbers for specific depths:

 * <DL>

 *    <DT><FONT SIZE="2">DEFAULT_LAYER</FONT></DT>

 *         <DD>The standard layer, where most components go. This the bottommost

 *         layer.

 *    <DT><FONT SIZE="2">PALETTE_LAYER</FONT></DT>

 *         <DD>The palette layer sits over the default layer. Useful for floating

 *         toolbars and palettes, so they can be positioned above other components.

 *    <DT><FONT SIZE="2">MODAL_LAYER</FONT></DT>

 *         <DD>The layer used for modal dialogs. They will appear on top of any

 *         toolbars, palettes, or standard components in the container.

 *    <DT><FONT SIZE="2">POPUP_LAYER</FONT></DT>

 *         <DD>The popup layer displays above dialogs. That way, the popup windows

 *         associated with combo boxes, tooltips, and other help text will appear

 *         above the component, palette, or dialog that generated them.

 *    <DT><FONT SIZE="2">DRAG_LAYER</FONT></DT>

 *         <DD>When dragging a component, reassigning it to the drag layer ensures

 *         that it is positioned over every other component in the container. When

 *         finished dragging, it can be reassigned to its normal layer.

 * </DL>

 * The <code>JLayeredPane</code> methods <code>moveToFront(Component)</code>,

 * <code>moveToBack(Component)</code> and <code>setPosition</code> can be used

 * to reposition a component within its layer. The <code>setLayer</code> method

 * can also be used to change the component's current layer.

 *

 * <h2>Details</h2>

 * <code>JLayeredPane</code> manages its list of children like

 * <code>Container</code>, but allows for the definition of a several

 * layers within itself. Children in the same layer are managed exactly

 * like the normal <code>Container</code> object,

 * with the added feature that when children components overlap, children

 * in higher layers display above the children in lower layers.

 * <p>

 * Each layer is a distinct integer number. The layer attribute can be set

 * on a <code>Component</code> by passing an <code>Integer</code>

 * object during the add call.<br> For example:

 * <PRE>

 *     layeredPane.add(child, JLayeredPane.DEFAULT_LAYER);

 * or

 *     layeredPane.add(child, new Integer(10));

 * </PRE>

 * The layer attribute can also be set on a Component by calling<PRE>

 *     layeredPaneParent.setLayer(child, 10)</PRE>

 * on the <code>JLayeredPane</code> that is the parent of component. The layer

 * should be set <i>before</i> adding the child to the parent.

 * <p>

 * Higher number layers display above lower number layers. So, using

 * numbers for the layers and letters for individual components, a

 * representative list order would look like this:<PRE>

 *       5a, 5b, 5c, 2a, 2b, 2c, 1a </PRE>

 * where the leftmost components are closest to the top of the display.

 * <p>

 * A component can be moved to the top or bottom position within its

 * layer by calling <code>moveToFront</code> or <code>moveToBack</code>.

 * <p>

 * The position of a component within a layer can also be specified directly.

 * Valid positions range from 0 up to one less than the number of

 * components in that layer. A value of -1 indicates the bottommost

 * position. A value of 0 indicates the topmost position. Unlike layer

 * numbers, higher position values are <i>lower</i> in the display.

 * <blockquote>

 * <b>Note:</b> This sequence (defined by java.awt.Container) is the reverse

 * of the layer numbering sequence. Usually though, you will use <code>moveToFront</code>,

 * <code>moveToBack</code>, and <code>setLayer</code>.

 * </blockquote>

 * Here are some examples using the method add(Component, layer, position):

 * Calling add(5x, 5, -1) results in:<PRE>

 *       5a, 5b, 5c, 5x, 2a, 2b, 2c, 1a </PRE>

 *

 * Calling add(5z, 5, 2) results in:<PRE>

 *       5a, 5b, 5z, 5c, 5x, 2a, 2b, 2c, 1a </PRE>

 *

 * Calling add(3a, 3, 7) results in:<PRE>

 *       5a, 5b, 5z, 5c, 5x, 3a, 2a, 2b, 2c, 1a </PRE>

 *

 * Using normal paint/event mechanics results in 1a appearing at the bottom

 * and 5a being above all other components.

 * <p>

 * <b>Note:</b> that these layers are simply a logical construct and LayoutManagers

 * will affect all child components of this container without regard for

 * layer settings.

 * <p>

 * <strong>Warning:</strong> Swing is not thread safe. For more

 * information see <a

 * href="package-summary.html#threading">Swing's Threading

 * Policy</a>.

 * <p>

 * <strong>Warning:</strong>

 * Serialized objects of this class will not be compatible with

 * future Swing releases. The current serialization support is

 * appropriate for short term storage or RMI between applications running

 * the same version of Swing.  As of 1.4, support for long term storage

 * of all JavaBeans<sup><font size="-2">TM</font></sup>

 * has been added to the <code>java.beans</code> package.

 * Please see {@link java.beans.XMLEncoder}.

 *

 * @author David Kloba

 */

public class JLayeredPane extends JComponent implements Accessible {

    /// Watch the values in getObjectForLayer()

    /** Convenience object defining the Default layer. Equivalent to new Integer(0).*/

    public final static Integer DEFAULT_LAYER = new Integer(0);

    /** Convenience object defining the Palette layer. Equivalent to new Integer(100).*/

    public final static Integer PALETTE_LAYER = new Integer(100);

    /** Convenience object defining the Modal layer. Equivalent to new Integer(200).*/

    public final static Integer MODAL_LAYER = new Integer(200);

    /** Convenience object defining the Popup layer. Equivalent to new Integer(300).*/

    public final static Integer POPUP_LAYER = new Integer(300);

    /** Convenience object defining the Drag layer. Equivalent to new Integer(400).*/

    public final static Integer DRAG_LAYER = new Integer(400);

    /** Convenience object defining the Frame Content layer.

      * This layer is normally only use to positon the contentPane and menuBar

      * components of JFrame.

      * Equivalent to new Integer(-30000).

      * @see JFrame

      */

    public final static Integer FRAME_CONTENT_LAYER = new Integer(-30000);

    /** Bound property */

    public final static String LAYER_PROPERTY = "layeredContainerLayer";

    // Hashtable to store layer values for non-JComponent components

    private Hashtable<Component,Integer> componentToLayer;

    private boolean optimizedDrawingPossible = true;

//////////////////////////////////////////////////////////////////////////////

//// Container Override methods

//////////////////////////////////////////////////////////////////////////////

    /** Create a new JLayeredPane */

    public JLayeredPane() {

        setLayout(null);

    }

    private void validateOptimizedDrawing() {

        boolean layeredComponentFound = false;

        synchronized(getTreeLock()) {

            Integer layer = null;

            for (Component c : getComponents()) {

                layer = null;

                if(c instanceof JInternalFrame || (c instanceof JComponent &&

                         (layer = (Integer)((JComponent)c).getClientProperty(

                          LAYER_PROPERTY)) != null)) {

                    if(layer != null && layer.equals(FRAME_CONTENT_LAYER))

                        continue;

                    layeredComponentFound = true;

                    break;

                }

            }

        }

        if(layeredComponentFound)

            optimizedDrawingPossible = false;

        else

            optimizedDrawingPossible = true;

    }

    protected void addImpl(Component comp, Object constraints, int index) {

        int layer = DEFAULT_LAYER.intValue();

        int pos;

        if(constraints instanceof Integer) {

            layer = ((Integer)constraints).intValue();

            setLayer(comp, layer);

        } else

            layer = getLayer(comp);

        pos = insertIndexForLayer(layer, index);

        super.addImpl(comp, constraints, pos);

        comp.validate();

        comp.repaint();

        validateOptimizedDrawing();

    }

    /**

     * Remove the indexed component from this pane.

     * This is the absolute index, ignoring layers.

     *

     * @param index  an int specifying the component to remove

     * @see #getIndexOf

     */

    public void remove(int index) {

        Component c = getComponent(index);

        super.remove(index);

        if (c != null && !(c instanceof JComponent)) {

            getComponentToLayer().remove(c);

        }

        validateOptimizedDrawing();

    }

    /**

     * Removes all the components from this container.

     *

     * @since 1.5

     */

    public void removeAll() {

        Component[] children = getComponents();

        Hashtable cToL = getComponentToLayer();

        for (int counter = children.length - 1; counter >= 0; counter--) {

            Component c = children[counter];

            if (c != null && !(c instanceof JComponent)) {

                cToL.remove(c);

            }

        }

        super.removeAll();

    }

    /**

     * Returns false if components in the pane can overlap, which makes

     * optimized drawing impossible. Otherwise, returns true.

     *

     * @return false if components can overlap, else true

     * @see JComponent#isOptimizedDrawingEnabled

     */

    public boolean isOptimizedDrawingEnabled() {

        return optimizedDrawingPossible;

    }

//////////////////////////////////////////////////////////////////////////////

//// New methods for managing layers

//////////////////////////////////////////////////////////////////////////////

    /** Sets the layer property on a JComponent. This method does not cause

      * any side effects like setLayer() (painting, add/remove, etc).

      * Normally you should use the instance method setLayer(), in order to

      * get the desired side-effects (like repainting).

      *

      * @param c      the JComponent to move

      * @param layer  an int specifying the layer to move it to

      * @see #setLayer

      */

    public static void putLayer(JComponent c, int layer) {

        /// MAKE SURE THIS AND setLayer(Component c, int layer, int position)  are SYNCED

        Integer layerObj;

        layerObj = new Integer(layer);

        c.putClientProperty(LAYER_PROPERTY, layerObj);

    }

    /** Gets the layer property for a JComponent, it

      * does not cause any side effects like setLayer(). (painting, add/remove, etc)

      * Normally you should use the instance method getLayer().

      *

      * @param c  the JComponent to check

      * @return   an int specifying the component's layer

      */

    public static int getLayer(JComponent c) {

        Integer i;

        if((i = (Integer)c.getClientProperty(LAYER_PROPERTY)) != null)

            return i.intValue();

        return DEFAULT_LAYER.intValue();

    }

    /** Convenience method that returns the first JLayeredPane which

      * contains the specified component. Note that all JFrames have a

      * JLayeredPane at their root, so any component in a JFrame will

      * have a JLayeredPane parent.

      *

      * @param c the Component to check

      * @return the JLayeredPane that contains the component, or

      *         null if no JLayeredPane is found in the component

      *         hierarchy

      * @see JFrame

      * @see JRootPane

      */

    public static JLayeredPane getLayeredPaneAbove(Component c) {

        if(c == null) return null;

        Component parent = c.getParent();

        while(parent != null && !(parent instanceof JLayeredPane))

            parent = parent.getParent();

        return (JLayeredPane)parent;

    }

    /** Sets the layer attribute on the specified component,

      * making it the bottommost component in that layer.

      * Should be called before adding to parent.

      *

      * @param c     the Component to set the layer for

      * @param layer an int specifying the layer to set, where

      *              lower numbers are closer to the bottom

      */

    public void setLayer(Component c, int layer)  {

        setLayer(c, layer, -1);

    }

    /** Sets the layer attribute for the specified component and

      * also sets its position within that layer.

      *

      * @param c         the Component to set the layer for

      * @param layer     an int specifying the layer to set, where

      *                  lower numbers are closer to the bottom

      * @param position  an int specifying the position within the

      *                  layer, where 0 is the topmost position and -1

      *                  is the bottommost position

      */

    public void setLayer(Component c, int layer, int position)  {

        Integer layerObj;

        layerObj = getObjectForLayer(layer);

        if(layer == getLayer(c) && position == getPosition(c)) {

                repaint(c.getBounds());

            return;

        }

        /// MAKE SURE THIS AND putLayer(JComponent c, int layer) are SYNCED

        if(c instanceof JComponent)

            ((JComponent)c).putClientProperty(LAYER_PROPERTY, layerObj);

        else

            getComponentToLayer().put((Component)c, layerObj);

        if(c.getParent() == null || c.getParent() != this) {

            repaint(c.getBounds());

            return;

        }

        int index = insertIndexForLayer(c, layer, position);

        setComponentZOrder(c, index);

        repaint(c.getBounds());

    }

    /**

     * Returns the layer attribute for the specified Component.

     *

     * @param c  the Component to check

     * @return an int specifying the component's current layer

     */

    public int getLayer(Component c) {

        Integer i;

        if(c instanceof JComponent)

            i = (Integer)((JComponent)c).getClientProperty(LAYER_PROPERTY);

        else

            i = (Integer)getComponentToLayer().get((Component)c);

        if(i == null)

            return DEFAULT_LAYER.intValue();

        return i.intValue();

    }

    /**

     * Returns the index of the specified Component.

     * This is the absolute index, ignoring layers.

     * Index numbers, like position numbers, have the topmost component

     * at index zero. Larger numbers are closer to the bottom.

     *

     * @param c  the Component to check

     * @return an int specifying the component's index

     */

    public int getIndexOf(Component c) {

        int i, count;

        count = getComponentCount();

        for(i = 0; i < count; i++) {

            if(c == getComponent(i))

                return i;

        }

        return -1;

    }

    /**

     * Moves the component to the top of the components in its current layer

     * (position 0).

     *

     * @param c the Component to move

     * @see #setPosition(Component, int)

     */

    public void moveToFront(Component c) {

        setPosition(c, 0);

    }

    /**

     * Moves the component to the bottom of the components in its current layer

     * (position -1).

     *

     * @param c the Component to move

     * @see #setPosition(Component, int)

     */

    public void moveToBack(Component c) {

        setPosition(c, -1);

    }

    /**

     * Moves the component to <code>position</code> within its current layer,

     * where 0 is the topmost position within the layer and -1 is the bottommost

     * position.

     * <p>

     * <b>Note:</b> Position numbering is defined by java.awt.Container, and

     * is the opposite of layer numbering. Lower position numbers are closer

     * to the top (0 is topmost), and higher position numbers are closer to

     * the bottom.

     *

     * @param c         the Component to move

     * @param position  an int in the range -1..N-1, where N is the number of

     *                  components in the component's current layer

     */

    public void setPosition(Component c, int position) {

        setLayer(c, getLayer(c), position);

    }

    /**

     * Get the relative position of the component within its layer.

     *

     * @param c  the Component to check

     * @return an int giving the component's position, where 0 is the

     *         topmost position and the highest index value = the count

     *         count of components at that layer, minus 1

     *

     * @see #getComponentCountInLayer

     */

    public int getPosition(Component c) {

        int i, count, startLayer, curLayer, startLocation, pos = 0;

        count = getComponentCount();

        startLocation = getIndexOf(c);

        if(startLocation == -1)

            return -1;

        startLayer = getLayer(c);

        for(i = startLocation - 1; i >= 0; i--) {

            curLayer = getLayer(getComponent(i));

            if(curLayer == startLayer)

                pos++;

            else

                return pos;

        }

        return pos;

    }

    /** Returns the highest layer value from all current children.

      * Returns 0 if there are no children.

      *

      * @return an int indicating the layer of the topmost component in the

      *         pane, or zero if there are no children

      */

    public int highestLayer() {

        if(getComponentCount() > 0)

            return getLayer(getComponent(0));

        return 0;

    }

    /** Returns the lowest layer value from all current children.

      * Returns 0 if there are no children.

      *

      * @return an int indicating the layer of the bottommost component in the

      *         pane, or zero if there are no children

      */

    public int lowestLayer() {

        int count = getComponentCount();

        if(count > 0)

            return getLayer(getComponent(count-1));

        return 0;

    }

    /**

     * Returns the number of children currently in the specified layer.

     *

     * @param layer  an int specifying the layer to check

     * @return an int specifying the number of components in that layer

     */

    public int getComponentCountInLayer(int layer) {

        int i, count, curLayer;

        int layerCount = 0;

        count = getComponentCount();

        for(i = 0; i < count; i++) {

            curLayer = getLayer(getComponent(i));

            if(curLayer == layer) {

                layerCount++;

            /// Short circut the counting when we have them all

            } else if(layerCount > 0 || curLayer < layer) {