content: /*******************************************************************************
   * Copyright (c) 2006, 2008 IBM Corporation and others.
   * All rights reserved. This program and the accompanying materials
   * are made available under the terms of the Eclipse Public License v1.0
   * which accompanies this distribution, and is available at
   * http://www.eclipse.org/legal/epl-v10.html
   *
   * Contributors:
   *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.wst.jsdt.internal.ui.javaeditor.saveparticipant;
  
  import java.util.ArrayList;
  import java.util.HashMap;
  import java.util.Iterator;
  import java.util.Map;
  
  import org.eclipse.core.resources.IProject;
  import org.eclipse.core.resources.ProjectScope;
  import org.eclipse.core.runtime.preferences.IScopeContext;
  import org.eclipse.wst.jsdt.internal.corext.fix.CleanUpPostSaveListener;
  import org.eclipse.wst.jsdt.internal.ui.fix.CleanUpSaveParticipantPreferenceConfiguration;
  
  /**
   * A registry for save participants. This registry manages
   * {@link SaveParticipantDescriptor}s and keeps track of enabled save
   * participants.
   * <p>
   * Save participants can be enabled and disabled on the Java &gt; Editor &gt;
   * Save Participants preference page. Enabled save participants are notified
   * through a call to
   * {@link IPostSaveListener#saved(org.eclipse.wst.jsdt.core.IJavaScriptUnit, org.eclipse.core.runtime.IProgressMonitor)}
   * whenever the {@link org.eclipse.wst.jsdt.internal.ui.javaeditor.CompilationUnitDocumentProvider} saves a compilation unit
   * that is in the workspace.</p>
   * <p>
   * An instance of this registry can be received through a call to {@link org.eclipse.wst.jsdt.internal.ui.JavaScriptPlugin#getSaveParticipantRegistry()}.</p>
   * 
   * 
   */
  public final class SaveParticipantRegistry {
  
  	private static final IPostSaveListener[] EMPTY_ARRAY= new IPostSaveListener[0];
      
  	/** The map of descriptors, indexed by their identifiers. */
  	private Map fDescriptors;
  
  	/**
  	 * Creates a new instance.
  	 */
  	public SaveParticipantRegistry() {
  	}
  
  	/**
  	 * Returns an array of <code>SaveParticipantDescriptor</code> describing
  	 * all registered save participants.
  	 *
  	 * @return the array of registered save participant descriptors
  	 */
  	public synchronized SaveParticipantDescriptor[] getSaveParticipantDescriptors() {
  		ensureRegistered();
  		return (SaveParticipantDescriptor[]) fDescriptors.values().toArray(new SaveParticipantDescriptor[fDescriptors.size()]);
  	}
  
  	/**
  	 * Returns the save participant descriptor for the given <code>id</code> or
  	 * <code>null</code> if no such listener is registered.
  	 *
  	 * @param id the identifier of the requested save participant
  	 * @return the corresponding descriptor, or <code>null</code> if none can be found
  	 */
  	public synchronized SaveParticipantDescriptor getSaveParticipantDescriptor(String id) {
  		ensureRegistered();
  		return (SaveParticipantDescriptor) fDescriptors.get(id);
  	}
  
  	/**
  	 * Ensures that all descriptors are created and stored in
  	 * <code>fDescriptors</code>.
  	 */
  	private void ensureRegistered() {
  		if (fDescriptors == null)
  			reloadDescriptors();
  	}
  
  	/**
  	 * Loads the save participants.
  	 * <p>
  	 * This method can be called more than once in
  	 * order to reload from a changed extension registry.
  	 * </p>
  	 */
  	private void reloadDescriptors() {
  		Map map= new HashMap();
  		SaveParticipantDescriptor desc= new SaveParticipantDescriptor(new CleanUpPostSaveListener()) {
  			/**
  			 * {@inheritDoc}
  			 */
  			public ISaveParticipantPreferenceConfiguration createPreferenceConfiguration() {
  				return new CleanUpSaveParticipantPreferenceConfiguration();
  			}
  		};	
  		map.put(desc.getId(), desc);
  				
  		fDescriptors= map;
  	}
  
  	public void dispose() {
  	}
  
  	/**
  	 * Checks weather there are enabled or disabled post save listener in the given context.
  	 * 
  	 * @param context to context to check, not null
  	 * @return true if there are settings in context
  	 */
  	public synchronized boolean hasSettingsInScope(IScopeContext context) {		
  		ensureRegistered();
  	
      	for (Iterator iterator= fDescriptors.values().iterator(); iterator.hasNext();) {
  	        SaveParticipantDescriptor descriptor= (SaveParticipantDescriptor)iterator.next();
  	        if (descriptor.getPreferenceConfiguration().hasSettingsInScope(context))
  	        	return true;
      	}
      	
      	return false;
      }
  	
  	public IPostSaveListener[] getEnabledPostSaveListeners(IProject project) {
  	    return getEnabledPostSaveListeners(new ProjectScope(project));
      }
  
  	/**
  	 * Returns an array of <code>IPostSaveListener</code> which are 
  	 * enabled in the given context.
  	 *
  	 * @param context the context from which to retrive the settings from, not null
  	 * @return the current enabled post save listeners according to the preferences
  	 */
  	public synchronized IPostSaveListener[] getEnabledPostSaveListeners(IScopeContext context) {
  		ensureRegistered();
  		
  		ArrayList result= null;
  		for (Iterator iterator= fDescriptors.values().iterator(); iterator.hasNext();) {
  			SaveParticipantDescriptor descriptor= (SaveParticipantDescriptor)iterator.next();
  			if (descriptor.getPreferenceConfiguration().isEnabled(context)) {
  				if (result == null) {
  					result= new ArrayList();
  				}
  				result.add(descriptor.getPostSaveListener());
  			}
  		}
  		
  		if (result == null) {
  			return EMPTY_ARRAY;
  		} else {
  			return (IPostSaveListener[])result.toArray(new IPostSaveListener[result.size()]);
  		}
  	}
  	
  }
  