JapsPluginLabelListener.java

/*
 *
 * Copyright 2005 AgileTec s.r.l. (http://www.agiletec.it) All rights reserved.
 *
 * This file is part of JAPS software.
 * JAPS and its  source-code is  licensed under the  terms of the
 * GNU General Public License  as published by  the Free Software
 * Foundation (http://www.fsf.org/licensing/licenses/gpl.txt).
 * 
 * You may copy, adapt, and redistribute this file for commercial
 * or non-commercial use.
 * When copying,  adapting,  or redistributing  this document you
 * are required to provide proper attribution  to AgileTec, using
 * the following attribution line:
 * Copyright 2005 AgileTec s.r.l. (http://www.agiletec.it) All rights reserved.
 *
 */
package com.agiletec.apsadmin.system.resource;

import java.io.InputStream;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Iterator;
import java.util.List;
import java.util.Set;
import java.util.jar.JarEntry;
import java.util.jar.JarInputStream;

import javax.servlet.ServletContextEvent;
import javax.servlet.ServletContextListener;

import com.agiletec.aps.system.ApsSystemUtils;
import com.opensymphony.xwork2.util.LocalizedTextUtil;

/**
 * This listener is used to add the properties of the plugins menu to the default resource bundles.
 * Note: this listener distinguishes between plugins under development and standard ones, that is,
 * those plugins found in the WEB-INF/classes/ directory and those normally installed in the 
 * WEB-INF/lib/ in the form of JAR files.
 * Apart the 'plugins' contained in the package, we rely on the 'apsadmin' being present soon
 * after the plugin name in the URL to distinguish between jAPS plugins and the others eventually
 * contained in the system libraries.
 * 
 * @author M. Minnai
 */
public class JapsPluginLabelListener implements ServletContextListener {

	@Override
	public void contextInitialized(ServletContextEvent event) {
		Set<String> jaredPlugins = new HashSet<String>();
		Set<String> classPlugins = new HashSet<String>();
		classPlugins = discoverClasses(TOMCAT_CLASSES, event);
		jaredPlugins = discoverJars(TOMCAT_LIB, event);
		Iterator<String> itr = classPlugins.iterator();
		while (itr.hasNext()) {
			String cur = itr.next();
			ApsSystemUtils.getLogger().info("Trying to load resources under development @ "+cur);
			LocalizedTextUtil.addDefaultResourceBundle(cur+this.PLUGIN_RESOURCE_NAME);
		}
		itr = jaredPlugins.iterator();
		while (itr.hasNext()) {
			String cur = itr.next();
			ApsSystemUtils.getLogger().info("Trying to load resources @ "+cur);
			LocalizedTextUtil.addDefaultResourceBundle(cur+this.PLUGIN_RESOURCE_NAME);
		}
		ApsSystemUtils.getLogger().info("JapsPluginLabelListener summary: "+(classPlugins.size()+jaredPlugins.size())+" plugin detected ("+classPlugins.size()+" under development)");
	}
		
	/**
	 * Discover the directories holding plugins within the classpath 
	 * @param path the path where to start the search from
	 * @param event the servlet context event
	 */
	private Set<String> discoverClasses(String path, ServletContextEvent event) {
		Set<String> plugins = new HashSet<String>();
		if (null==path || event==null) return plugins;
		Set<String> directory = event.getServletContext().getResourcePaths(path);
		if (null != directory && !directory.isEmpty()) {
			Iterator<String> itr = directory.iterator();
			while (itr.hasNext()) {
				String currentDirectory=itr.next();
				boolean skip = false;
				// AVOID USELESS LOOPS IF POSSIBLE
				Iterator<String> exclude = _plugin_exclusion_directories.iterator();
				while (exclude.hasNext()) {
					String currentDirectoryExcluded = exclude.next();
					if (currentDirectory.contains(currentDirectoryExcluded) 
							&& !currentDirectory.contains(PLUGIN_DIRECTORY)) {
						skip = true;
						break;
					}
				}
				if (skip) continue;
				if (currentDirectory.contains(PLUGIN_DIRECTORY)
						&& currentDirectory.endsWith(PLUGIN_APSADMIN_PATH)) {
					currentDirectory = currentDirectory.replaceFirst(TOMCAT_CLASSES, "");
					plugins.add(currentDirectory);
				} else {
					plugins.addAll(discoverClasses(currentDirectory, event));
				}
			}
		}
		return plugins;
	}
	
	private Set<String> discoverJars(String path, ServletContextEvent event) {
		Set<String> plugins = new HashSet<String>();
		Set<String> directory = event.getServletContext().getResourcePaths(path);
		Iterator<String> itr = directory.iterator();
		// ITERATE OVER PATHS
		while (null != itr && itr.hasNext()) {
			String currentJar = itr.next();
			InputStream is=event.getServletContext().getResourceAsStream(currentJar);
			plugins.addAll(discoverJarPlugin(is));
		}
		return plugins;
	}

	/**
	 * Fetch all the entries in the given (jar) input stream and look for the
	 * plugin directory.
	 * @param is the input stream to analyse
	 */
	private Set<String> discoverJarPlugin(InputStream is) {
		Set<String> plugins = new HashSet<String>();
		if (null==is) return plugins;
		JarEntry je = null;
		try {
			JarInputStream jis = new JarInputStream(is);
			do {
				je = jis.getNextJarEntry();
				if (null != je) {
					String URL=je.toString();
					if (URL.contains(PLUGIN_DIRECTORY)
							&& URL.endsWith(PLUGIN_APSADMIN_PATH)) {
						plugins.add(URL);
					}
				}
			} while (je != null);
		} catch (Throwable t) {
			ApsSystemUtils.logThrowable(t, this, "discoverJarPlugin");
		}
		return plugins; 
	}
	
	@Override
	public void contextDestroyed(ServletContextEvent arg0) {
		// nothing to do
	}
	
	/**
	 * This contains all the directories to exclude from the recursive search when 
	 * PLUGIN_DIRECTORY does NOT exist in the URL or path
	 */
	private List<String> _plugin_exclusion_directories = Arrays.asList("/test/",
			"/aps/",
			"/apsadmin/");

	/**
	 * Path within the plugin where the global properties are stored.
	 */
	private final String PLUGIN_APSADMIN_PATH = "/apsadmin/";

	/**
	 * Path to the global properties file within the plugin package
	 */
	private final String PLUGIN_RESOURCE_NAME = "global-messages";
	
	/**
	 * This is the directory where plugins are searched
	 */
	private final String PLUGIN_DIRECTORY = "plugins";
	
	/**
	 * The URL of Tomcat classes
	 */
	private String TOMCAT_CLASSES = "/WEB-INF/classes/";
	
	/**
	 * The URL of the Tomcat shared lib directory
	 */
	private String TOMCAT_LIB = "/WEB-INF/lib/";
}