/* * Copyright (c) 2000 David Flanagan.  All rights reserved. * This code is from the book Java Examples in a Nutshell, 2nd Edition. * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied. * You may study, use, and modify it for any non-commercial purpose. * You may distribute it non-commercially as long as you retain this notice. * For a commercial use license, or to purchase the book (recommended), * visit http://www.davidflanagan.com/javaexamples2. */package com.davidflanagan.examples.gui;import com.davidflanagan.examples.reflect.*;import java.awt.event.*;import javax.swing.*;import java.util.*;/** * This class parses an Action object from a GUIResourceBundle. * The specified key is used to look up the Command string for the action. * The key is also used as a prefix for other resource names that specify * other attributes (such as the label and icon) associated with the Action. * An action named "zoomOut" might be specified like this: *  *      zoomOut: zoom(0.5); *      zoomOut.label: Zoom Out *      zoomOut.description: Zoom out by a factor of 2 *  * Because Action objects are often reused by an application (for example * in a toolbar and a menu system, this ResourceParser caches the Action * objects it returns.  By sharing Action objects, you can disable and enable * an action and that change will affect the entire GUI. **/public class ActionParser implements ResourceParser {    static final Class[] supportedTypes = new Class[] { Action.class };    public Class[] getResourceTypes() { return supportedTypes; }    HashMap bundleToCacheMap = new HashMap();    public Object parse(GUIResourceBundle bundle, String key, Class type)	throws java.util.MissingResourceException    {	// Look up the Action cache associated with this bundle	HashMap cache = (HashMap) bundleToCacheMap.get(bundle);	if (cache == null) {  // If there isn't one, create one and save it	    cache = new HashMap();	    bundleToCacheMap.put(bundle, cache);	}	// Now look up the Action associated with the key in the cache.	Action action = (Action) cache.get(key);	// If we found a cached action, return it.	if (action != null) return action;	// If there was no cached action create one.  The command is	// the only required resource.  It will throw an exception if	// missing or malformed.	Command command = (Command) bundle.getResource(key, Command.class);	// The remaining calls all supply default values, so they will not	// throw exceptions, even if ResourceParsers haven't been registered	// for types like Icon and KeyStroke	String label = bundle.getString(key + ".label", null);	Icon icon = (Icon) bundle.getResource(key + ".icon", Icon.class, null);	String tooltip = bundle.getString(key + ".description", null);	KeyStroke accelerator = 	    (KeyStroke) bundle.getResource(key + ".accelerator", 					   KeyStroke.class, null);	int mnemonic = bundle.getInt(key + ".mnemonic", KeyEvent.VK_UNDEFINED);	boolean enabled = bundle.getBoolean(key + ".enabled", true);	// Create a CommandAction object with these values	action = new CommandAction(command, label, icon, tooltip,				   accelerator, mnemonic, enabled);	// Save it in the cache, then return it	cache.put(key, action);	return action;    }}