bundles/org.eclipse.gef/src/org/eclipse/gef/palette/ToolEntry.java

/*******************************************************************************
 * 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.util.HashMap;
import java.util.Map;

import org.eclipse.core.runtime.Assert;
import org.eclipse.jface.resource.ImageDescriptor;

import org.eclipse.gef.Tool;

/**
 * A factory for returning Tools.
 */
public abstract class ToolEntry extends PaletteEntry {

	/** Type Identifier **/
	public static final Object PALETTE_TYPE_TOOL = "$Palette Tool";//$NON-NLS-1$

	private Map map;
	private Class toolClass;

	/**
	 * Creates a new ToolEntry. Any parameter can be <code>null</code>.
	 * 
	 * @param label
	 *            the entry's name
	 * @param shortDesc
	 *            the entry's description
	 * @param iconSmall
	 *            the entry's small icon
	 * @param iconLarge
	 *            the entry's large icon
	 */
	public ToolEntry(String label, String shortDesc, ImageDescriptor iconSmall,
			ImageDescriptor iconLarge) {
		this(label, shortDesc, iconSmall, iconLarge, null);
	}

	/**
	 * Constructor to create a new ToolEntry. Any parameter can be
	 * <code>null</code>.
	 * 
	 * @param label
	 *            the entry's name
	 * @param description
	 *            the entry's description
	 * @param iconSmall
	 *            the entry's small icon
	 * @param iconLarge
	 *            the entry's large icon
	 * @param tool
	 *            the type of tool that this entry uses
	 * @since 3.1
	 */
	public ToolEntry(String label, String description,
			ImageDescriptor iconSmall, ImageDescriptor iconLarge, Class tool) {
		super(label, description, iconSmall, iconLarge, PALETTE_TYPE_TOOL);
		setToolClass(tool);
	}

	/**
	 * Creates the tool of the type specified by {@link #setToolClass(Class)}
	 * for this ToolEntry. The tool is also configured with the properties set
	 * in {@link #setToolProperty(Object, Object)}. Sub-classes overriding this
	 * method should ensure that their tools are also configured with those
	 * properties.
	 * 
	 * @return the tool for this entry
	 */
	public Tool createTool() {
		if (toolClass == null)
			return null;
		Tool tool;
		try {
			tool = (Tool) toolClass.newInstance();
		} catch (IllegalAccessException iae) {
			return null;
		} catch (InstantiationException ie) {
			return null;
		}
		tool.setProperties(getToolProperties());
		return tool;
	}

	/**
	 * @return the properties set in {@link #setToolProperty(Object, Object)}
	 * @since 3.1
	 */
	protected Map getToolProperties() {
		return map;
	}

	/**
	 * Returns the property value for the specified property key.
	 * 
	 * @param key
	 *            the property key
	 * @return the value for the requested property
	 * @since 3.1
	 */
	public Object getToolProperty(Object key) {
		if (map != null)
			return map.get(key);
		return null;
	}

	/**
	 * Sets the type of tool to be created. This provides clients with a method
	 * of specifying a different type of tool to be created without having to
	 * sub-class. The provided class should have a default constructor for this
	 * to work successfully.
	 * 
	 * @param toolClass
	 *            the type of tool to be created by this entry
	 * @since 3.1
	 */
	public void setToolClass(Class toolClass) {
		if (toolClass != null)
			Assert.isTrue(Tool.class.isAssignableFrom(toolClass));
		this.toolClass = toolClass;
	}

	/**
	 * Clients can use this method to configure the associated tool without
	 * having to sub-class.
	 * 
	 * @param key
	 *            the property name
	 * @param value
	 *            a value of type associated with the given property
	 * @since 3.1
	 * @see Tool#setProperties(Map)
	 */
	public void setToolProperty(Object key, Object value) {
		if (map == null)
			map = new HashMap();
		map.put(key, value);
	}

}