001    /*
002     * Copyright (C) 2010 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 org.slf4j.Logger;
022    import org.slf4j.LoggerFactory;
023    
024    import java.util.ArrayList;
025    import java.util.ServiceConfigurationError;
026    import java.util.ServiceLoader;
027    
028    /**
029     * @author <a href="mailto:julien.viet@exoplatform.com">Julien Viet</a>
030     */
031    public class ServiceLoaderDiscovery implements PluginDiscovery {
032    
033      /** . */
034      private static final Logger log = LoggerFactory.getLogger(PluginManager.class);
035    
036      /** . */
037      private final ClassLoader classLoader;
038    
039      /**
040       * Create a new instance.
041       *
042       * @param classLoader the loader for the discovery
043       * @throws NullPointerException if the loader argument is null
044       */
045      public ServiceLoaderDiscovery(ClassLoader classLoader) throws NullPointerException {
046        if (classLoader == null) {
047          throw new NullPointerException();
048        }
049    
050        //
051        this.classLoader = classLoader;
052      }
053    
054      public Iterable<CRaSHPlugin<?>> getPlugins() {
055    
056        //
057        ArrayList<CRaSHPlugin<?>> plugins = new ArrayList<CRaSHPlugin<?>>();
058        try {
059          ServiceLoader<CRaSHPlugin> loader = ServiceLoader.load(CRaSHPlugin.class, classLoader);
060          for (CRaSHPlugin<?> plugin : loader) {
061            log.info("Loaded plugin " + plugin);
062            plugins.add(plugin);
063          }
064        }
065        catch (ServiceConfigurationError e) {
066          log.error("Could not load plugins", e);
067        }
068    
069        //
070        return plugins;
071      }
072    }