/*
    * Copyright 2006-2013 the original author or authors.
    *
    * 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.springframework.batch.core.listener;
  
  import java.util.Iterator;
  import java.util.List;
  
  import org.springframework.batch.core.ChunkListener;
  import org.springframework.batch.core.scope.context.ChunkContext;
  import org.springframework.core.Ordered;
  
  /**
   * @author Lucas Ward
   *
   */
  public class CompositeChunkListener implements ChunkListener {
  
  	private OrderedComposite<ChunkListener> listeners = new OrderedComposite<ChunkListener>();
  
  	/**
  	 * Public setter for the listeners.
  	 *
  	 * @param listeners
  	 */
  	public void setListeners(List<? extends ChunkListener> listeners) {
  		this.listeners.setItems(listeners);
  	}
  
  	/**
  	 * Register additional listener.
  	 *
  	 * @param chunkListener
  	 */
  	public void register(ChunkListener chunkListener) {
  		listeners.add(chunkListener);
  	}
  
  	/**
  	 * Call the registered listeners in order, respecting and prioritizing those
  	 * that implement {@link Ordered}.
  	 *
  	 * @see org.springframework.batch.core.ChunkListener#afterChunk(ChunkContext context)
  	 */
  	@Override
  	public void afterChunk(ChunkContext context) {
  		for (Iterator<ChunkListener> iterator = listeners.iterator(); iterator.hasNext();) {
  			ChunkListener listener = iterator.next();
  			listener.afterChunk(context);
  		}
  	}
  
  	/**
  	 * Call the registered listeners in reverse order.
  	 *
  	 * @see org.springframework.batch.core.ChunkListener#beforeChunk(ChunkContext context)
  	 */
  	@Override
  	public void beforeChunk(ChunkContext context) {
  		for (Iterator<ChunkListener> iterator = listeners.reverse(); iterator.hasNext();) {
  			ChunkListener listener = iterator.next();
  			listener.beforeChunk(context);
  		}
  	}
  
  	@Override
  	public void afterChunkError(ChunkContext context) {
  		for (Iterator<ChunkListener> iterator = listeners.iterator(); iterator.hasNext();) {
  			ChunkListener listener = iterator.next();
  			listener.afterChunkError(context);
  		}
  	}
  }