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 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    public class ServiceLoaderDiscovery implements PluginDiscovery {
029    
030      /** . */
031      private static final Logger log = LoggerFactory.getLogger(PluginManager.class);
032    
033      /** . */
034      private final ClassLoader classLoader;
035    
036      /**
037       * Create a new instance.
038       *
039       * @param classLoader the loader for the discovery
040       * @throws NullPointerException if the loader argument is null
041       */
042      public ServiceLoaderDiscovery(ClassLoader classLoader) throws NullPointerException {
043        if (classLoader == null) {
044          throw new NullPointerException();
045        }
046    
047        //
048        this.classLoader = classLoader;
049      }
050    
051      public Iterable<CRaSHPlugin<?>> getPlugins() {
052    
053        //
054        ArrayList<CRaSHPlugin<?>> plugins = new ArrayList<CRaSHPlugin<?>>();
055        try {
056          ServiceLoader<CRaSHPlugin> loader = ServiceLoader.load(CRaSHPlugin.class, classLoader);
057          for (CRaSHPlugin<?> plugin : loader) {
058            log.info("Loaded plugin " + plugin);
059            plugins.add(plugin);
060          }
061        }
062        catch (ServiceConfigurationError e) {
063          log.error("Could not load plugins", e);
064        }
065    
066        //
067        return plugins;
068      }
069    }