EDIT

/*******************************************************************************

 * Copyright (c) 2000, 2010 IBM Corporation and others.

 * All rights reserved. This program and the accompanying materials

 * are made available under the terms of the Eclipse Public License v1.0

 * which accompanies this distribution, and is available at

 * http://www.eclipse.org/legal/epl-v10.html

 *

 * Contributors:

 *     IBM Corporation - initial API and implementation

 *******************************************************************************/

package org.eclipse.gef.palette;

import java.beans.PropertyChangeEvent;

import java.beans.PropertyChangeListener;

import java.util.Collection;

import java.util.Collections;

import java.util.Iterator;

import java.util.List;

import org.eclipse.jface.resource.ImageDescriptor;

/**

 * The model object for a PaletteStack - A stack of tools. A stack should

 * contain only tools and should have permissions that are less than or equal to

 * its parent.

 * 

 * @author Whitney Sorenson

 * @since 3.0

 */

public class PaletteStack extends PaletteContainer {

	/**

	 * Listens to visibility changes of the children palette entries so that the

	 * active entry can be updated if the current active entry is hidden.

	 */

	private PropertyChangeListener childListener = new PropertyChangeListener() {

		public void propertyChange(PropertyChangeEvent evt) {

			if (evt.getPropertyName().equals(PaletteEntry.PROPERTY_VISIBLE)

					&& evt.getNewValue() == Boolean.FALSE

					&& activeEntry == evt.getSource()) {

				checkActiveEntry();

			}

		}

	};

	/** Type identifier **/

	public static final String PALETTE_TYPE_STACK = "$PaletteStack"; //$NON-NLS-1$

	/** Property name for the active entry **/

	public static final String PROPERTY_ACTIVE_ENTRY = "Active Entry"; //$NON-NLS-1$

	private PaletteEntry activeEntry;

	/**

	 * Creates a new PaletteStack with the given name, description, and icon.

	 * These will be shown only in the customize menu. Any of the given

	 * parameter can be <code>null</code>.

	 * 

	 * @param name

	 *            the stack's name

	 * @param desc

	 *            the stack's description

	 * @param icon

	 *            an ImageDescriptor for the stack's small icon

	 * @see PaletteContainer#PaletteContainer(String, String, ImageDescriptor,

	 *      Object)

	 */

	public PaletteStack(String name, String desc, ImageDescriptor icon) {

		super(name, desc, icon, PALETTE_TYPE_STACK);

		setUserModificationPermission(PERMISSION_LIMITED_MODIFICATION);

	}

	/**

	 * Returns true if this type can be a child of this container Only accepts

	 * ToolEntry's.

	 * 

	 * @param type

	 *            the type being requested

	 * @return true if this can be a child of this container

	 */

	public boolean acceptsType(Object type) {

		if (!type.equals(ToolEntry.PALETTE_TYPE_TOOL))

			return false;

		return super.acceptsType(type);

	}

	/**

	 * @see org.eclipse.gef.palette.PaletteContainer#add(int,

	 *      org.eclipse.gef.palette.PaletteEntry)

	 */

	public void add(int index, PaletteEntry entry) {

		super.add(index, entry);

		checkActiveEntry();

	}

	/**

	 * @see org.eclipse.gef.palette.PaletteContainer#addAll(java.util.List)

	 */

	public void addAll(List list) {

		super.addAll(list);

		checkActiveEntry();

		updateListeners(list, true);

	}

	/**

	 * Checks to make sure the active entry is up-to-date and sets it to the

	 * first child if it is <code>null</code>.

	 */

	private void checkActiveEntry() {

		PaletteEntry currEntry = activeEntry;

		if (!getChildren().contains(activeEntry))

			activeEntry = null;

		if (activeEntry == null && getChildren().size() > 0)

			activeEntry = (PaletteEntry) getChildren().get(0);

		if (activeEntry != null && !activeEntry.isVisible()) {

			for (Iterator iterator = getChildren().iterator(); iterator

					.hasNext();) {

				PaletteEntry child = (PaletteEntry) iterator.next();

				if (child.isVisible()) {

					activeEntry = child;

					break;

				}

				activeEntry = null;

			}

		}

		listeners.firePropertyChange(PROPERTY_ACTIVE_ENTRY, currEntry,

				activeEntry);

	}

	/**

	 * Returns the PaletteEntry referring to the active entry that should be

	 * shown in the palette.

	 * 

	 * @return active entry to be shown in the palette.

	 */

	public PaletteEntry getActiveEntry() {

		checkActiveEntry();

		return activeEntry;

	}

	/**

	 * @see org.eclipse.gef.palette.PaletteContainer#remove(org.eclipse.gef.palette.PaletteEntry)

	 */

	public void remove(PaletteEntry entry) {

		super.remove(entry);

		checkActiveEntry();

		updateListeners(Collections.singletonList(entry), false);

	}

	/**

	 * Sets the "active" child entry to the given PaletteEntry. This entry will

	 * be shown on the palette and will be checked in the menu.

	 * 

	 * @param entry

	 *            the entry to show on the palette.

	 */

	public void setActiveEntry(PaletteEntry entry) {

		PaletteEntry oldEntry = activeEntry;

		if (activeEntry != null

				&& (activeEntry.equals(entry) || !getChildren().contains(entry)))

			return;

		activeEntry = entry;

		listeners.firePropertyChange(PROPERTY_ACTIVE_ENTRY, oldEntry,

				activeEntry);

	}

	public void add(PaletteEntry entry) {

		super.add(entry);

		updateListeners(Collections.singletonList(entry), true);

	}

	public void setChildren(List list) {

		updateListeners(getChildren(), false);

		super.setChildren(list);

		updateListeners(getChildren(), true);

		checkActiveEntry();

	}

	/**

	 * Either adds or remove the <code>childListener</code> to each palette

	 * entry in the collection.

	 * 

	 * @param entries

	 *            a collection of <code>PaletteEntries</code>

	 * @param add

	 *            true if the lister should be added; false if it should be

	 *            removed

	 */

	private void updateListeners(Collection entries, boolean add) {

		for (Iterator iterator = entries.iterator(); iterator.hasNext();) {

			PaletteEntry child = (PaletteEntry) iterator.next();

			if (add) {

				child.addPropertyChangeListener(childListener);

			} else {

				child.removePropertyChangeListener(childListener);

			}

		}

	}

}