/* * 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.StringTokenizer;/** * This class parses a JMenu or JPopupMenu from textual descriptions found in * a GUIResourceBundle.  The grammar is straightforward: the menu label * followed by a colon and a list of menu items.  Menu items that begin with * a '>' character are submenus.  Menu items that begin with a '-' character * are separators.  All other items are action names. **/public class MenuParser implements ResourceParser {    static final Class[] supportedTypes = new Class[] {	JMenu.class, JPopupMenu.class  // This class handles two resource types    };    public Class[] getResourceTypes() { return supportedTypes; }    public Object parse(GUIResourceBundle bundle, String key, Class type)	throws java.util.MissingResourceException    {	// Get the string value of the key	String menudef = bundle.getString(key);	// Break it up into words, ignoring whitespace, colons and commas	StringTokenizer st = new StringTokenizer(menudef, " \t:,");	// The first word is the label of the menu	String menuLabel = st.nextToken();	// Create either a JMenu or JPopupMenu	JMenu menu = null;	JPopupMenu popup = null;	if (type == JMenu.class) menu = new JMenu(menuLabel);	else popup = new JPopupMenu(menuLabel);	// Then loop through the rest of the words, creating a JMenuItem	// for each one.  Accumulate these items in a list	while(st.hasMoreTokens()) {	    String item = st.nextToken();     // the next word	    char firstchar = item.charAt(0);  // determines type of menu item	    switch(firstchar) {	    case '-':   // words beginning with - add a separator to the menu		if (menu != null) menu.addSeparator();		else popup.addSeparator();		break;	    case '>':   // words beginning with > are submenu names		// strip off the > character, and recurse to parse the submenu		item = item.substring(1);  		// Parse a submenu and add it to the list of items		JMenu submenu = (JMenu)parse(bundle, item, JMenu.class);		if (menu != null) menu.add(submenu);		else popup.add(submenu);		break;	    case '!': // words beginning with ! are action names		item = item.substring(1);   // strip off the ! character		/* falls through */         // fall through to the next case	    default:  // By default all other words are taken as action names		// Look up the named action and add it to the menu		Action action = (Action)bundle.getResource(item, Action.class);		if (menu != null) menu.add(action);		else popup.add(action);		break;	    }	}	// Finally, return the menu or the popup menu	if (menu != null) return menu;	else return popup;    }}