MenuHandler.java

/*******************************************************************************
 * Copyright (c) 2003-2005, 2013 Till Zoppke.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the GNU Public License v3.0
 * which accompanies this distribution, and is available at
 * http://www.gnu.org/licenses/gpl.html
 * 
 * Contributors:
 *     Till Zoppke - initial API and implementation
 ******************************************************************************/
/*
 * Created on 25.03.2004
 */
package eniac.menu;

import java.io.IOException;
import java.io.InputStream;
import java.util.Hashtable;

import javax.swing.AbstractButton;
import javax.swing.JMenu;
import javax.swing.JMenuBar;
import javax.swing.JMenuItem;
import javax.swing.JToolBar;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;

import eniac.Manager;
import eniac.io.IOUtil;
import eniac.io.XMLUtil;
import eniac.menu.action.EAction;
import eniac.util.EProperties;

/**
 * @author zoppke
 */
public class MenuHandler extends DefaultHandler {

	// constant tag and attribute names for parsing the menu xml file
	private enum Tag {
		MENU, GROUP, ACTION, NAME, MENUBAR, TOOLBAR, SEPARATOR, KEY, SID;
	}

	// Enum representing the parsing state (FSM)
	private enum ParsingState {
		DEFAULT, TOOLBAR, MENUBAR;
	}

	// =============================== fields //================================

	private Hashtable<String, EAction> _actionDefaults = null;

	private JMenu _currentMenu = null;

	private JToolBar _toolBar = null;

	private JMenuBar _menuBar = null;

	private ParsingState _parsingState = ParsingState.DEFAULT;

	private Hashtable<String, EAction> _actions = new Hashtable<>();

	// ============================ lifecycle //================================

	public MenuHandler(Hashtable<String, EAction> actionDefaults) {
		_actionDefaults = actionDefaults;
	}

	public void init() {

		// parse menu and toolbar from xml
		String path = EProperties.getInstance().getProperty("MENU_FILE");
		InputStream in = Manager.class.getClassLoader().getResourceAsStream(path);
		try {
			IOUtil.parse(in, this);
		} catch (IOException e) {
			e.printStackTrace();
		}
	}

	// ========================== defaultHandler methods //=====================

	public void startElement(String uri, String localName, String qName, Attributes attrs) throws SAXException {
		// System.out.println(qName);

		try {
			Tag tag = Enum.valueOf(Tag.class, qName.toUpperCase());

			switch (tag) {

				case TOOLBAR :
					// create jtoolbar and adjust parsing state
					_toolBar = new JToolBar();
					_parsingState = ParsingState.TOOLBAR;
					break;

				case ACTION :
					if (_parsingState == ParsingState.MENUBAR) {

						// add action to jmenu
						String key = XMLUtil.parseString(attrs, Tag.KEY);
						EAction action = getAction(key);
						_currentMenu.add((JMenuItem) action.getValue(EAction.ITEM));
					}
					else if (_parsingState == ParsingState.TOOLBAR) {

						// add action to toolbar
						String key = XMLUtil.parseString(attrs, Tag.KEY);
						EAction action = getAction(key);
						_toolBar.add((AbstractButton) action.getValue(EAction.BUTTON));
					}
					break;

				case SEPARATOR :
					if (_parsingState == ParsingState.TOOLBAR) {

						// add separator to toolbar
						_toolBar.addSeparator();
					}
					else if (_parsingState == ParsingState.MENUBAR) {

						// add separator to menu
						_currentMenu.addSeparator();
					}
					break;

				case MENUBAR :

					// create jmenubar and adjust parsing state
					_menuBar = new JMenuBar();
					_parsingState = ParsingState.MENUBAR;
					break;

				case GROUP :

					// create jmenu and add it to menubar
					String sid = XMLUtil.parseString(attrs, Tag.SID);
					_currentMenu = new EMenu(sid);
					_menuBar.add(_currentMenu);
					break;

				default :
					break;
			}
		} catch (Exception e) {
			// important: catch any exception and print its tree.
			// otherwise you won't get the error's source.
			e.printStackTrace();
			throw new SAXException(e);
		}
	}

	// =========================== other methods //=============================

	public JToolBar getToolBar() {
		return _toolBar;
	}

	public JMenuBar getMenuBar() {
		return _menuBar;
	}

	private EAction getAction(String key) {
		EAction action = _actions.get(key);

		// if action is not present in our table, get it from the action manager
		if (action == null) {
			action = ActionManager.getInstance().getAction(key);

			// add action defaults
			for (String s : _actionDefaults.keySet()) {
				action.putValue(s, _actionDefaults.get(s));
			}
			// init action and store it at our table
			action.init();
			_actions.put(key, action);
		}
		// return action
		return action;
	}
}