PluginUtil.java

/*
 * This program is free software; you can redistribute it and/or modify it under the 
 * terms of the GNU Lesser General Public License, version 2.1 as published by the Free Software 
 * Foundation.
 *
 * You should have received a copy of the GNU Lesser General Public License along with this 
 * program; if not, you can obtain a copy at http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html 
 * or from the Free Software Foundation, Inc., 
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * 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 Lesser General Public License for more details.
 *
 * Copyright 2009 Pentaho Corporation.  All rights reserved.
 *
 * Created June 17 2009
 * @author aphillips
 */
package org.pentaho.platform.plugin.services.pluginmgr;

import org.pentaho.platform.api.engine.IPluginManager;
import org.pentaho.platform.engine.core.system.PentahoSessionHolder;
import org.pentaho.platform.engine.core.system.PentahoSystem;

public class PluginUtil {
  
  /**
   * If the service specified by <code>serviceId</code> is supplied by a plugin,
   * the ClassLoader used to load classes for the associated plugin is returned.
   * This is a handy method to use if you want to find resources associated with 
   * a particular (plugin-supplied) service, such as a GWT serialization policy
   * file, properties files, etc.  If the service was not supplied by a plugin,
   * then <code>null</code> is returned.
   * 
   * @param path a path to a plugin resource
   * @return the ClassLoader that serves the (plugin-supplied) service, or <code>null</code> if
   * the service was not plugin-supplied or the plugin manager cannot identify the service.
   */
  public static ClassLoader getClassLoaderForService(String path) {
    IPluginManager pluginManager = PentahoSystem.get(IPluginManager.class, PentahoSessionHolder.getSession());

    //The plugin manager can tell us which plugin handles requests like the one for the serialization file
    //
    String servicePluginId = pluginManager.getServicePlugin(path);

    if (servicePluginId == null) {
      return null;
    }

    return pluginManager.getClassLoader(servicePluginId);
  }

}