/*

 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. 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.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

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 * questions.

 */

package javax.swing;

import java.util.List;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Iterator;

import javax.swing.plaf.*;

import javax.accessibility.*;

import java.awt.Component;

import java.awt.Container;

import java.awt.DefaultFocusTraversalPolicy;

import java.awt.FocusTraversalPolicy;

import java.awt.Window;

import java.io.ObjectOutputStream;

import java.io.ObjectInputStream;

import java.io.IOException;

import java.beans.PropertyVetoException;

import java.util.Set;

import java.util.TreeSet;

/**

 * A container used to create a multiple-document interface or a virtual desktop.

 * You create <code>JInternalFrame</code> objects and add them to the

 * <code>JDesktopPane</code>. <code>JDesktopPane</code> extends

 * <code>JLayeredPane</code> to manage the potentially overlapping internal

 * frames. It also maintains a reference to an instance of

 * <code>DesktopManager</code> that is set by the UI

 * class for the current look and feel (L&amp;F).  Note that <code>JDesktopPane</code>

 * does not support borders.

 * <p>

 * This class is normally used as the parent of <code>JInternalFrames</code>

 * to provide a pluggable <code>DesktopManager</code> object to the

 * <code>JInternalFrames</code>. The <code>installUI</code> of the

 * L&F specific implementation is responsible for setting the

 * <code>desktopManager</code> variable appropriately.

 * When the parent of a <code>JInternalFrame</code> is a <code>JDesktopPane</code>,

 * it should delegate most of its behavior to the <code>desktopManager</code>

 * (closing, resizing, etc).

 * <p>

 * For further documentation and examples see

 * <a href="http://docs.oracle.com/javase/tutorial/uiswing/components/internalframe.html">How to Use Internal Frames</a>,

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

 * <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

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

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

 *

 * @see JInternalFrame

 * @see JInternalFrame.JDesktopIcon

 * @see DesktopManager

 *

 * @author David Kloba

 */

public class JDesktopPane extends JLayeredPane implements Accessible

{

    /**

     * @see #getUIClassID

     * @see #readObject

     */

    private static final String uiClassID = "DesktopPaneUI";

    transient DesktopManager desktopManager;

    private transient JInternalFrame selectedFrame = null;

    /**

      * Indicates that the entire contents of the item being dragged

      * should appear inside the desktop pane.

      *

      * @see #OUTLINE_DRAG_MODE

      * @see #setDragMode

      */

    public static final int LIVE_DRAG_MODE = 0;

    /**

      * Indicates that an outline only of the item being dragged

      * should appear inside the desktop pane.

      *

      * @see #LIVE_DRAG_MODE

      * @see #setDragMode

      */

    public static final int OUTLINE_DRAG_MODE = 1;

    private int dragMode = LIVE_DRAG_MODE;

    private boolean dragModeSet = false;

    private transient List<JInternalFrame> framesCache;

    private boolean componentOrderCheckingEnabled = true;

    private boolean componentOrderChanged = false;

    /**

     * Creates a new <code>JDesktopPane</code>.

     */

    public JDesktopPane() {

        setUIProperty("opaque", Boolean.TRUE);

        setFocusCycleRoot(true);

        setFocusTraversalPolicy(new LayoutFocusTraversalPolicy() {

            public Component getDefaultComponent(Container c) {

                JInternalFrame jifArray[] = getAllFrames();

                Component comp = null;

                for (JInternalFrame jif : jifArray) {

                    comp = jif.getFocusTraversalPolicy().getDefaultComponent(jif);

                    if (comp != null) {

                        break;

                    }

                }

                return comp;

            }

        });

        updateUI();

    }

    /**

     * Returns the L&F object that renders this component.

     *

     * @return the <code>DesktopPaneUI</code> object that

     *   renders this component

     */

    public DesktopPaneUI getUI() {

        return (DesktopPaneUI)ui;

    }

    /**

     * Sets the L&F object that renders this component.

     *

     * @param ui  the DesktopPaneUI L&F object

     * @see UIDefaults#getUI

     * @beaninfo

     *        bound: true

     *       hidden: true

     *    attribute: visualUpdate true

     *  description: The UI object that implements the Component's LookAndFeel.

     */

    public void setUI(DesktopPaneUI ui) {

        super.setUI(ui);

    }

    /**

     * Sets the "dragging style" used by the desktop pane.

     * You may want to change to one mode or another for

     * performance or aesthetic reasons.

     *

     * @param dragMode the style of drag to use for items in the Desktop

     *

     * @see #LIVE_DRAG_MODE

     * @see #OUTLINE_DRAG_MODE

     *

     * @beaninfo

     *        bound: true

     *  description: Dragging style for internal frame children.

     *         enum: LIVE_DRAG_MODE JDesktopPane.LIVE_DRAG_MODE

     *               OUTLINE_DRAG_MODE JDesktopPane.OUTLINE_DRAG_MODE

     * @since 1.3

     */

    public void setDragMode(int dragMode) {

        int oldDragMode = this.dragMode;

        this.dragMode = dragMode;

        firePropertyChange("dragMode", oldDragMode, this.dragMode);

        dragModeSet = true;

     }

    /**

     * Gets the current "dragging style" used by the desktop pane.

     * @return either <code>Live_DRAG_MODE</code> or

     *   <code>OUTLINE_DRAG_MODE</code>

     * @see #setDragMode

     * @since 1.3

     */

     public int getDragMode() {

         return dragMode;

     }

    /**

     * Returns the <code>DesktopManger</code> that handles

     * desktop-specific UI actions.

     */

    public DesktopManager getDesktopManager() {

        return desktopManager;

    }

    /**

     * Sets the <code>DesktopManger</code> that will handle

     * desktop-specific UI actions. This may be overridden by

     * {@code LookAndFeel}.

     *

     * @param d the <code>DesktopManager</code> to use

     *

     * @beaninfo

     *        bound: true

     *  description: Desktop manager to handle the internal frames in the

     *               desktop pane.

     */

    public void setDesktopManager(DesktopManager d) {

        DesktopManager oldValue = desktopManager;

        desktopManager = d;

        firePropertyChange("desktopManager", oldValue, desktopManager);

    }

    /**

     * Notification from the <code>UIManager</code> that the L&amp;F has changed.

     * Replaces the current UI object with the latest version from the

     * <code>UIManager</code>.

     *

     * @see JComponent#updateUI

     */

    public void updateUI() {

        setUI((DesktopPaneUI)UIManager.getUI(this));

    }

    /**

     * Returns the name of the L&F class that renders this component.

     *

     * @return the string "DesktopPaneUI"

     * @see JComponent#getUIClassID

     * @see UIDefaults#getUI

     */

    public String getUIClassID() {

        return uiClassID;

    }

    /**

     * Returns all <code>JInternalFrames</code> currently displayed in the

     * desktop. Returns iconified frames as well as expanded frames.

     *

     * @return an array of <code>JInternalFrame</code> objects

     */

    public JInternalFrame[] getAllFrames() {

        return getAllFrames(this).toArray(new JInternalFrame[0]);

    }

    private static Collection<JInternalFrame> getAllFrames(Container parent) {

        int i, count;

        Collection<JInternalFrame> results = new ArrayList<JInternalFrame>();

        count = parent.getComponentCount();

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

            Component next = parent.getComponent(i);

            if (next instanceof JInternalFrame) {

                results.add((JInternalFrame) next);

            } else if (next instanceof JInternalFrame.JDesktopIcon) {

                JInternalFrame tmp = ((JInternalFrame.JDesktopIcon) next).getInternalFrame();

                if (tmp != null) {

                    results.add(tmp);

                }

            } else if (next instanceof Container) {

                results.addAll(getAllFrames((Container) next));

            }

        }

        return results;

    }

    /** Returns the currently active <code>JInternalFrame</code>

      * in this <code>JDesktopPane</code>, or <code>null</code>

      * if no <code>JInternalFrame</code> is currently active.

      *

      * @return the currently active <code>JInternalFrame</code> or

      *   <code>null</code>

      * @since 1.3

      */

    public JInternalFrame getSelectedFrame() {

      return selectedFrame;

    }

    /** Sets the currently active <code>JInternalFrame</code>

     *  in this <code>JDesktopPane</code>. This method is used to bridge

     *  the package gap between JDesktopPane and the platform implementation

     *  code and should not be called directly. To visually select the frame

     *  the client must call JInternalFrame.setSelected(true) to activate

     *  the frame.

     *  @see JInternalFrame#setSelected(boolean)

     *

     * @param f the internal frame that's currently selected

     * @since 1.3

     */

    public void setSelectedFrame(JInternalFrame f) {

      selectedFrame = f;

    }

    /**

     * Returns all <code>JInternalFrames</code> currently displayed in the

     * specified layer of the desktop. Returns iconified frames as well

     * expanded frames.

     *

     * @param layer  an int specifying the desktop layer

     * @return an array of <code>JInternalFrame</code> objects

     * @see JLayeredPane

     */

    public JInternalFrame[] getAllFramesInLayer(int layer) {

        Collection<JInternalFrame> allFrames = getAllFrames(this);

        Iterator<JInternalFrame> iterator = allFrames.iterator();

        while (iterator.hasNext()) {

            if (iterator.next().getLayer() != layer) {

                iterator.remove();

            }

        }

        return allFrames.toArray(new JInternalFrame[0]);

    }

    private List<JInternalFrame> getFrames() {

        Component c;

        Set<ComponentPosition> set = new TreeSet<ComponentPosition>();

        for (int i = 0; i < getComponentCount(); i++) {

            c = getComponent(i);

            if (c instanceof JInternalFrame) {

                set.add(new ComponentPosition((JInternalFrame)c, getLayer(c),

                    i));

            }

            else if (c instanceof JInternalFrame.JDesktopIcon)  {

                c = ((JInternalFrame.JDesktopIcon)c).getInternalFrame();

                set.add(new ComponentPosition((JInternalFrame)c, getLayer(c),

                    i));

            }

        }

        List<JInternalFrame> frames = new ArrayList<JInternalFrame>(

                set.size());

        for (ComponentPosition position : set) {

            frames.add(position.component);

        }

        return frames;

   }

    private static class ComponentPosition implements

        Comparable<ComponentPosition> {

        private final JInternalFrame component;

        private final int layer;

        private final int zOrder;

        ComponentPosition(JInternalFrame component, int layer, int zOrder) {

            this.component = component;

            this.layer = layer;

            this.zOrder = zOrder;

        }

        public int compareTo(ComponentPosition o) {

            int delta = o.layer - layer;

            if (delta == 0) {

                return zOrder - o.zOrder;

            }

            return delta;

        }

    }

    private JInternalFrame getNextFrame(JInternalFrame f, boolean forward) {

        verifyFramesCache();

        if (f == null) {

            return getTopInternalFrame();

        }

        int i = framesCache.indexOf(f);

        if (i == -1 || framesCache.size() == 1) {

            /* error */

            return null;

        }

        if (forward) {

            // navigate to the next frame

            if (++i == framesCache.size()) {

                /* wrap */

                i = 0;

            }

        }

        else {

            // navigate to the previous frame

            if (--i == -1) {

                /* wrap */

                i = framesCache.size() - 1;

            }

        }

        return framesCache.get(i);

    }

    JInternalFrame getNextFrame(JInternalFrame f) {

        return getNextFrame(f, true);

    }

    private JInternalFrame getTopInternalFrame() {

        if (framesCache.size() == 0) {

            return null;

        }

        return framesCache.get(0);

    }

    private void updateFramesCache() {

        framesCache = getFrames();

    }

    private void verifyFramesCache() {

        // If framesCache is dirty, then recreate it.

        if (componentOrderChanged) {

            componentOrderChanged = false;

            updateFramesCache();

        }

    }

    /**

     * {@inheritDoc}

     */

    @Override

    public void remove(Component comp) {

        super.remove(comp);

        updateFramesCache();

    }

    /**

     * Selects the next <code>JInternalFrame</code> in this desktop pane.

     *

     * @param forward a boolean indicating which direction to select in;

     *        <code>true</code> for forward, <code>false</code> for

     *        backward

     * @return the JInternalFrame that was selected or <code>null</code>

     *         if nothing was selected

     * @since 1.6

     */

    public JInternalFrame selectFrame(boolean forward) {

        JInternalFrame selectedFrame = getSelectedFrame();

        JInternalFrame frameToSelect = getNextFrame(selectedFrame, forward);

        if (frameToSelect == null) {

            return null;

        }

        // Maintain navigation traversal order until an

        // external stack change, such as a click on a frame.

        setComponentOrderCheckingEnabled(false);

        if (forward && selectedFrame != null) {

            selectedFrame.moveToBack();  // For Windows MDI fidelity.

        }

        try { frameToSelect.setSelected(true);

        } catch (PropertyVetoException pve) {}

        setComponentOrderCheckingEnabled(true);

        return frameToSelect;

    }

    /*

     * Sets whether component order checking is enabled.

     * @param enable a boolean value, where <code>true</code> means

     * a change in component order will cause a change in the keyboard

     * navigation order.

     * @since 1.6

     */

    void setComponentOrderCheckingEnabled(boolean enable) {

        componentOrderCheckingEnabled = enable;

    }

    /**

     * {@inheritDoc}

     * @since 1.6

     */

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

        super.addImpl(comp, constraints, index);

        if (componentOrderCheckingEnabled) {

            if (comp instanceof JInternalFrame ||

                comp instanceof JInternalFrame.JDesktopIcon) {

                componentOrderChanged = true;

            }

        }

    }

    /**

     * {@inheritDoc}

     * @since 1.6

     */

    public void remove(int index) {

        if (componentOrderCheckingEnabled) {

            Component comp = getComponent(index);

            if (comp instanceof JInternalFrame ||

                comp instanceof JInternalFrame.JDesktopIcon) {

                componentOrderChanged = true;

            }

        }

        super.remove(index);

    }

    /**

     * {@inheritDoc}

     * @since 1.6

     */

    public void removeAll() {

        if (componentOrderCheckingEnabled) {

            int count = getComponentCount();

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

                Component comp = getComponent(i);

                if (comp instanceof JInternalFrame ||

                    comp instanceof JInternalFrame.JDesktopIcon) {

                    componentOrderChanged = true;

                    break;

                }

            }

        }