/*
    * Copyright (C) 2007-2012 Argeo GmbH
    *
    * Licensed under the Apache 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.apache.org/licenses/LICENSE-2.0
    *
   * 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.argeo.jcr;
  
  import javax.jcr.RepositoryException;
  import javax.jcr.Session;
  import javax.jcr.observation.Event;
  import javax.jcr.observation.EventIterator;
  import javax.jcr.observation.EventListener;
  import javax.jcr.observation.ObservationManager;
  
  import org.apache.commons.logging.Log;
  import org.apache.commons.logging.LogFactory;
  
  /** To be overridden */
  public class DefaultJcrListener implements EventListener {
  	private final static Log log = LogFactory.getLog(DefaultJcrListener.class);
  	private Session session;
  	private String path = "/";
  	private Boolean deep = true;
  
  	public void start() {
  		try {
  			addEventListener(session().getWorkspace().getObservationManager());
  			if (log.isDebugEnabled())
  				log.debug("Registered JCR event listener on " + path);
  		} catch (Exception e) {
  			throw new ArgeoJcrException("Cannot register event listener", e);
  		}
  	}
  
  	public void stop() {
  		try {
  			session().getWorkspace().getObservationManager()
  					.removeEventListener(this);
  			if (log.isDebugEnabled())
  				log.debug("Unregistered JCR event listener on " + path);
  		} catch (Exception e) {
  			throw new ArgeoJcrException("Cannot unregister event listener", e);
  		}
  	}
  
  	/** Default is listen to all events */
  	protected Integer getEvents() {
  		return Event.NODE_ADDED | Event.NODE_REMOVED | Event.PROPERTY_ADDED
  				| Event.PROPERTY_CHANGED | Event.PROPERTY_REMOVED;
  	}
  
  	/** To be overidden */
  	public void onEvent(EventIterator events) {
  		while (events.hasNext()) {
  			Event event = events.nextEvent();
  			log.debug(event);
  		}
  	}
  
  	/** To be overidden */
  	protected void addEventListener(ObservationManager observationManager)
  			throws RepositoryException {
  		observationManager.addEventListener(this, getEvents(), path, deep,
  				null, null, false);
  	}
  
  	private Session session() {
  		return session;
  	}
  
  	public void setPath(String path) {
  		this.path = path;
  	}
  
  	public void setDeep(Boolean deep) {
  		this.deep = deep;
  	}
  
  	public void setSession(Session session) {
  		this.session = session;
  	}
  
  }