001    /*
002     * Copyright (C) 2012 eXo Platform SAS.
003     *
004     * This is free software; you can redistribute it and/or modify it
005     * under the terms of the GNU Lesser General Public License as
006     * published by the Free Software Foundation; either version 2.1 of
007     * the License, or (at your option) any later version.
008     *
009     * This software is distributed in the hope that it will be useful,
010     * but WITHOUT ANY WARRANTY; without even the implied warranty of
011     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
012     * Lesser General Public License for more details.
013     *
014     * You should have received a copy of the GNU Lesser General Public
015     * License along with this software; if not, write to the Free
016     * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
017     * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
018     */
019    package org.crsh.plugin;
020    
021    import java.util.ArrayList;
022    import java.util.ServiceConfigurationError;
023    import java.util.ServiceLoader;
024    import java.util.logging.Level;
025    import java.util.logging.Logger;
026    
027    public class ServiceLoaderDiscovery implements PluginDiscovery {
028    
029      /** . */
030      private static final Logger log = Logger.getLogger(PluginManager.class.getName());
031    
032      /** . */
033      private final ClassLoader classLoader;
034    
035      /**
036       * Create a new instance.
037       *
038       * @param classLoader the loader for the discovery
039       * @throws NullPointerException if the loader argument is null
040       */
041      public ServiceLoaderDiscovery(ClassLoader classLoader) throws NullPointerException {
042        if (classLoader == null) {
043          throw new NullPointerException();
044        }
045    
046        //
047        this.classLoader = classLoader;
048      }
049    
050      public Iterable<CRaSHPlugin<?>> getPlugins() {
051    
052        //
053        ArrayList<CRaSHPlugin<?>> plugins = new ArrayList<CRaSHPlugin<?>>();
054        try {
055          ServiceLoader<CRaSHPlugin> loader = ServiceLoader.load(CRaSHPlugin.class, classLoader);
056          for (CRaSHPlugin<?> plugin : loader) {
057            log.log(Level.INFO, "Loaded plugin " + plugin);
058            plugins.add(plugin);
059          }
060        }
061        catch (ServiceConfigurationError e) {
062          log.log(Level.SEVERE, "Could not load plugins", e);
063        }
064    
065        //
066        return plugins;
067      }
068    }