/*

 * Copyright 1997-2008 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.plaf.basic;

import javax.swing.*;

import java.awt.*;

import java.awt.event.*;

import java.beans.*;

/**

 * DesktopIconMover is intended to move desktop icon

 * when parent window is resized.

 */

class DesktopIconMover implements ComponentListener, PropertyChangeListener {

    private Component parent;

    private JInternalFrame frame; // if not null, DesktopIconMover(frame)

                                  // constructor was used

    private JInternalFrame.JDesktopIcon icon;

    private Rectangle parentBounds;

    private boolean componentListenerAdded = false;

    public DesktopIconMover(JInternalFrame frame) {

        if (frame == null) {

            throw new NullPointerException("Frame cannot be null");

        }

        this.frame = frame;

        this.icon = frame.getDesktopIcon();

        if (icon == null) {

            throw new NullPointerException(

                    "frame.getDesktopIcon() cannot be null");

        }

        this.parent = frame.getParent();

        if (this.parent != null) {

            parentBounds = this.parent.getBounds();

        }

    }

    public DesktopIconMover(JInternalFrame.JDesktopIcon icon) {

        if (icon == null) {

            throw new NullPointerException("Icon cannot be null");

        }

        this.icon = icon;

        this.parent = icon.getParent();

        if (this.parent != null) {

            parentBounds = this.parent.getBounds();

        }

    }

    public void installListeners() {

        if (frame != null) {

            frame.addPropertyChangeListener(this);

        } else {

            icon.addPropertyChangeListener(this);

        }

        addComponentListener();

    }

    public void uninstallListeners() {

        if (frame != null) {

            frame.removePropertyChangeListener(this);

        } else {

            icon.removePropertyChangeListener(this);

        }

        removeComponentListener();

    }

    public void propertyChange(PropertyChangeEvent evt) {

        String propName = evt.getPropertyName();

        if ("ancestor".equals(propName)) {

            Component newAncestor = (Component) evt.getNewValue();

            // Remove component listener if parent is changing

            Component probablyNewParent = getCurrentParent();

            if ((probablyNewParent != null) &&

                    (!probablyNewParent.equals(parent))) {

                removeComponentListener();

                parent = probablyNewParent;

            }

            if (newAncestor == null) {

                removeComponentListener();

            } else {

                addComponentListener();

            }

            // Update parentBounds

            if (parent != null) {

                parentBounds = parent.getBounds();

            } else {

                parentBounds = null;

            }

        } else if (JInternalFrame.IS_CLOSED_PROPERTY.equals(propName)) {

            removeComponentListener();

        }

    }

    private void addComponentListener() {

        if (!componentListenerAdded && (parent != null)) {

            parent.addComponentListener(this);

            componentListenerAdded = true;

        }

    }

    private void removeComponentListener() {

        if ((parent != null) && componentListenerAdded) {

            parent.removeComponentListener(this);

            componentListenerAdded = false;

        }

    }

    private Component getCurrentParent() {

        if (frame != null) {

            return frame.getParent();

        } else {

            return icon.getParent();

        }

    }

    public void componentResized(ComponentEvent e) {

        if ((parent == null) || (parentBounds == null)) {

            return;

        }

        Rectangle parentNewBounds = parent.getBounds();

        if ((parentNewBounds == null) || parentNewBounds.equals(parentBounds)) {

            return;

        }

        // Move desktop icon only in up-down direction

        int newIconY = icon.getLocation().y +

                (parentNewBounds.height - parentBounds.height);

        icon.setLocation(icon.getLocation().x, newIconY);

        parentBounds = parentNewBounds;

    }

    public void componentMoved(ComponentEvent e) {

    }

    public void componentShown(ComponentEvent e) {

    }

    public void componentHidden(ComponentEvent e) {

    }

}