/**
    * Copyright 2005-2011 The Kuali Foundation
    *
    * Licensed under the Educational Community License, Version 2.0 (the "License");
    * you may not use this file except in compliance with the License.
    * You may obtain a copy of the License at
    *
    * http://www.opensource.org/licenses/ecl2.php
    *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  package org.kuali.rice.kew.plugin;
  
  import java.util.ArrayList;
  import java.util.Collections;
  import java.util.List;
  
  import javax.xml.namespace.QName;
  
  import org.kuali.rice.core.api.config.CoreConfigHelper;
  import org.kuali.rice.core.api.resourceloader.ResourceLoader;
  import org.kuali.rice.core.api.resourceloader.ResourceLoaderContainer;
  
  /**
   * A base class for {@link PluginRegistry} implementations.  Is essentially a ResourceLoader 
   * implementation that ensures plugins are the only ResourceLoaders used.  Also maintains
   * information about the PluginEnvironments of the loaded plugins in this registry.
   * 
   * @see Plugin
   * @see PluginEnvironment
   * 
   * @author Kuali Rice Team (rice.collab@kuali.org)
   */
  public abstract class BasePluginRegistry extends ResourceLoaderContainer implements PluginRegistry {
  	
  	private List<PluginEnvironment> pluginEnvironments = Collections.synchronizedList(new ArrayList<PluginEnvironment>());
  	
  	public BasePluginRegistry() {
  		super(new QName(CoreConfigHelper.getApplicationId(), ResourceLoader.PLUGIN_REGISTRY_LOADER_NAME));
  	}
  	
  	public BasePluginRegistry(QName name) {
  		super(name);
  	}
  	    
      public PluginEnvironment getPluginEnvironment(String pluginName) {
      	for (PluginEnvironment environment : pluginEnvironments) {
      		if (environment.getPluginName().equals(pluginName)) {
      			return environment;
      		}
      	}
      	return null;
      }
  	
  	public void addPluginEnvironment(PluginEnvironment pluginEnvironment) {
  		// chances are that this plugin has already been added to the resource loader
  		if (pluginEnvironment.getPlugin() != null && !containsResourceLoader(pluginEnvironment.getPlugin())) {
  			addResourceLoader(pluginEnvironment.getPlugin());
  		}
  		pluginEnvironments.add(pluginEnvironment);
  	}
  	
  	public PluginEnvironment removePluginEnvironment(String pluginName) {
  	    PluginEnvironment environment = getPluginEnvironment(pluginName);
          if (environment == null) {
              return null;
          }
          if (environment.getPlugin() != null) {
              super.removeResourceLoader(environment.getPlugin().getName());
          }
  		if (!pluginEnvironments.remove(environment)) {
  			return null;
  		}
  		return environment;
  	}
  
  	public Plugin getPlugin(QName pluginName) {
  		return (Plugin)getResourceLoader(pluginName);
  	}
  
  	public List<QName> getPluginNames() {
  		return super.getResourceLoaderNames();
  	}
  	
  	public List<PluginEnvironment> getPluginEnvironments() {
  		return Collections.unmodifiableList(pluginEnvironments);
  	}
  }