plugin.java

著名的开源仿真软件yale

/*
 *  YALE - Yet Another Learning Environment
 *  Copyright (C) 2002, 2003
 *      Simon Fischer, Ralf Klinkenberg, Ingo Mierswa, 
 *          Katharina Morik, Oliver Ritthoff
 *      Artificial Intelligence Unit
 *      Computer Science Department
 *      University of Dortmund
 *      44221 Dortmund,  Germany
 *  email: [e-mail]
 *  web:   http://yale.cs.uni-dortmund.de/
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License as 
 *  published by the Free Software Foundation; either version 2 of the
 *  License, or (at your option) any later version. 
 *
 *  This program is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 *  General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
 *  USA.
 */
package edu.udo.cs.yale.tools.plugin;

import edu.udo.cs.yale.Yale;
import edu.udo.cs.yale.tools.ParameterService;
import edu.udo.cs.yale.tools.OperatorService;
import edu.udo.cs.yale.tools.LogService;

import java.util.jar.JarFile;
import java.util.jar.JarEntry;
import java.util.List;
import java.util.Iterator;
import java.util.LinkedList;
import java.io.File;
import java.io.Reader;
import java.io.FilenameFilter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLClassLoader;

/**
 *  @version $Id: Plugin.java,v 1.3 2003/09/03 14:27:28 fischer Exp $
 */
public class Plugin {

    private JarFile archive;
    private ClassLoader classLoader;

    public Plugin(File file) throws IOException {
	archive = new JarFile(file);
	URL url = new URL("file", null, file.getAbsolutePath());
	this.classLoader = new URLClassLoader(new URL[] { url });
    }

    public void register() {
	URL operatorsURL = classLoader.getResource("operators.xml");
	if (operatorsURL == null) {
	    LogService.logMessage("Plugin '"+archive.getName()+"' does not contain operators.xml!",
				  LogService.ERROR);
	} else {
	    Reader reader = null;
	    try {
		reader = new InputStreamReader(operatorsURL.openStream());
	    } catch (IOException e) {
		LogService.logMessage("Cannot read operators.xml from '"+archive.getName()+"'!",
				      LogService.ERROR);
	    }
	    Yale.getInstance().splashMessage("Loading "+archive.getName());
	    LogService.logMessage("Loading "+archive.getName(), LogService.INIT);
	    OperatorService.registerOperators(archive.getName(),
					      reader,
					      classLoader);
	}
    }

    /** Returns a list of Plugins found in the plugins directory. */
    public static List findPlugins() {
	File pluginDir = ParameterService.getPluginDir();
	if (!(pluginDir.exists() &&
	      pluginDir.isDirectory())) return new LinkedList();
	File[] files = pluginDir.listFiles(new FilenameFilter() {
		public boolean accept(File dir, String name) {
		    return name.endsWith(".jar");
		}
	    });
	List plugins = new LinkedList();
	for (int i = 0; i < files.length; i++) {
	    try {
		plugins.add(new Plugin(files[i]));
	    } catch (Throwable e) {
		LogService.logException("Cannot load plugin '"+files[i]+"'", e);
	    }
	}
	return plugins;
    }

    /** Returns a list of Plugins found in the plugins directory. */
    public static void registerAllPlugins() {
	List plugins = findPlugins();
	if (plugins.size() > 0) {
	    LogService.logMessage("Found "+plugins.size()+" plugins in "+ParameterService.getPluginDir(), 
				  LogService.INIT);
	    Iterator i = plugins.iterator();
	    while(i.hasNext()) {
		((Plugin)i.next()).register();
	    }
	}
    }

}