butormenu.java

一个实用工具类

/*
 * Copyright (C) butor.com. All rights reserved.
 *
 * This software is published under the terms of the GNU Library General
 * Public License (GNU LGPL), a copy of which has been included with this
 * distribution in the LICENSE.txt file. 
 */


package org.butor.web.menu;

import java.net.URLEncoder;
import java.util.Arrays;
import java.util.Collection;
import java.util.Comparator;
import java.util.Iterator;
import java.util.Locale;

import org.butor.log.Log;
import org.butor.messageResources.MessageResourcesService;

/**
 * Menu items' wrapper class. This class provides sorting facility.
 * How the items are sorted is based on an Comparator object.
 *
 * @author Nguyen The Hung
 */
public class ButorMenu {

	/** 
	 * Top node (dummy node, i.e. placeholder for all children nodes).
	 */
	private Branch f_topNode;
	private String f_id;
	/**
	 * Comparator for sorting.
	 */
	private Comparator f_comparator;
	private Locale f_locale;
	private boolean f_hasChanged;

	/**
	 * Constructor for ButorMenu.
	 */
	public ButorMenu(String id, MenuItem[] topLevelBranches, Locale locale) {

		super();

		f_id = id;
		f_topNode = new Branch("", "");
		for (int i = 0; i < topLevelBranches.length; i++) {
			f_topNode.addBranch(topLevelBranches[i]);
		}
		setLocale(locale);
	}

	/**
	 * Recursively change the label for the current node and all the children nodes.
	 * @param MenuItem org.butor.wak.menu.MenuItem
	 */
	protected void changeLabel(MenuItem node) {

		if (node == null) {
			Log.logStr(this, Log.LOG_TYPE_ERROR, "changeLabel()", "Cannot change menu label [null].");
			return;
		}
		
		String label = MessageResourcesService.getMessage(f_locale, node.getLabelKey());
		node.setLabel(label);
		if (node.isTitledAction()) {
			String action = node.getAction();
			String actionWithTitle = mergeTitleToAction(action, node.getLabelKey());
			node.setActionWithTitle(actionWithTitle);
		}
		if (node.hasChild()) {
			// change the label for the children nodes
			Collection nodes = node.getChildren();
			for (Iterator it = nodes.iterator(); it.hasNext();) {
				changeLabel((MenuItem) it.next());
			}
		}
	}

	protected String mergeTitleToAction(String action, String labelKey) {
		// If the menu item is flagged as titled_action, append the label to the
		// title parameter on action URL.
		if (action != null) {
			StringBuffer actionBuffer = new StringBuffer(action);
			if (action.indexOf('?') != -1) {
				actionBuffer.append("&");
			} else {
				actionBuffer.append("?");
			}
			actionBuffer.append("titleKey=" + URLEncoder.encode(labelKey));
			
			action = actionBuffer.toString();
		}
		return action;
	}
	
	/**
	 * Set locale.
	 * @param locale java.util.Locale
	 */
	public void setLocale(Locale locale) {

		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "setLocale()", "");
		
		if (f_locale != locale) {
			f_locale = locale;
			f_hasChanged = true;

			Collection nodes = f_topNode.getChildren();
			for (Iterator it = nodes.iterator(); it.hasNext();) {
				changeLabel((MenuItem) it.next());
			}
		}
	}

	/**
	 * Set the comparator for sorting
	 * @param comparator java.util.comparator
	 */
	public void setComparator(Comparator comparator) {

		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "setComparator()", "");
		
		if (f_comparator != comparator) {
			f_comparator = comparator;
			f_hasChanged = true;
		}
	}
	
	/**
	 * Sort the nodes using the current comparator.
	 */
	public void sort() {
		
		Log.logStr(Log.LOG_LEVEL_LOW, this, Log.LOG_TYPE_INFO, "sort()", "");
		
		if (f_hasChanged) {
			sort(f_topNode);
			f_hasChanged = false;
		}
	}
	
	/**
	 * Recursively sort the children nodes.
	 * @param Node org.butor.wak.menu
	 */
	protected void sort(Branch node) {

		if (f_comparator != null && node.hasChild()) {
			
			Collection branches = node.getChildren();
			Branch nodes[] = new Branch[branches.size()];
			branches.toArray(nodes);
			
			try {
				Arrays.sort(nodes, f_comparator);
			} catch (ClassCastException e) {
				Log.logException(this, Log.LOG_TYPE_WARN, "sort(Branch node)", e);
				return;
			}

			node.removeAllChildren();
			for (int i = 0; i < nodes.length; i++) {
				node.addBranch(nodes[i]);
			}
			
			// sort the "grand-children"
			for (int i = 0; i < nodes.length; i++) {
				sort(nodes[i]);
			}
		}
	}
	
	/**
	 * Return the name of the menu
	 * @return java.lang.String
	 */
	public String getId() {
		return f_id;
	}
	
	/**
	 * Return the locale
	 * @return java.util.Locale
	 */
	public Locale getLocale() {
		return f_locale;
	}
	
	/**
	 * Return the comparator object.
	 * @return java.util.Comparator
	 */
	public Comparator getComparator() {
		return f_comparator;
	}
	
	/**
	 * Return the menu items
	 * @return org.butor.wak.menu.IMenuItem []
	 */
	public IMenuItem[] getItems() {
		Collection menus = f_topNode.getChildren();
		MenuItem menuItems[] = new MenuItem[menus.size()];

		menus.toArray(menuItems);
		return menuItems;
	}

	/**
	 * Return a menu item
	 * @return org.butor.wak.menu.IMenuItem
	 */
	public IMenuItem getItem(String id) {
		return (IMenuItem)f_topNode.getBranch(id);
	}
}