SerializableChunkProcessor.java

package es.fcs.batch.integration.chunk;

/* Copyright 2004-2010 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.
 */

import java.io.Serializable;

import org.springframework.batch.core.JobExecutionException;
import org.springframework.batch.core.StepContribution;
import org.springframework.batch.core.step.item.Chunk;
import org.springframework.batch.core.step.item.ChunkProcessor;
import org.springframework.batch.core.step.item.SimpleChunkProcessor;
import org.springframework.batch.item.ItemProcessor;
import org.springframework.batch.item.ItemWriter;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.util.Assert;

/**
 * 
 * @author Alois Cochard
 */
public class SerializableChunkProcessor<I, O> implements ChunkProcessor<I>,
		InitializingBean, Serializable {

	private static final long serialVersionUID = 1L;

	private transient ItemProcessor<? super I, ? extends O> itemProcessor;

	private transient ItemWriter<? super O> itemWriter;

	private transient SimpleChunkProcessor<I, O> delegate;

	private Serializable itemProcessorSerializable;

	private Serializable itemWriterSerializable;

	public SerializableChunkProcessor(
			ItemProcessor<? super I, ? extends O> itemProcessor,
			ItemWriter<? super O> itemWriter) {
		this.itemProcessor = itemProcessor;
		this.itemWriter = itemWriter;
		validate();
	}

	@SuppressWarnings("unused")
	private SerializableChunkProcessor() {

	}

	public void afterPropertiesSet() throws Exception {
		validate();
	}

	public void process(StepContribution contribution, Chunk<I> inputs)
			throws Exception {
		doInit();
		delegate.process(contribution, inputs);
	}

	public void setItemProcessor(
			ItemProcessor<? super I, ? extends O> itemProcessor) {
		this.itemProcessor = itemProcessor;
	}

	public void setItemWriter(ItemWriter<? super O> itemWriter) {
		this.itemWriter = itemWriter;
	}

	@SuppressWarnings("unchecked")
	private void doInit() throws JobExecutionException {
		if (delegate != null) {
			// Delegate is already initialized
			return;
		}

		// Initializing processor and writer
		if (itemWriter == null && itemWriterSerializable == null) {
			throw new JobExecutionException("No itemWriter defined");
		}
		if (itemProcessor == null && itemProcessorSerializable == null) {
			throw new JobExecutionException("No itemWriter defined");
		}
		if (itemWriter == null)
			itemWriter = (ItemWriter) itemWriterSerializable;
		if (itemProcessor == null)
			itemProcessor = (ItemProcessor) itemProcessorSerializable;

		// Initializing delegate
		delegate = new SimpleChunkProcessor<I, O>(itemProcessor, itemWriter);
	}

	private void validate() {
		Assert.notNull(itemProcessor, "itemProcessor is required");
		Assert.notNull(itemWriter, "itemWriter is required");
		Assert.isInstanceOf(Serializable.class, itemProcessor,
				"itemProcessor must implement Serializable");
		Assert.isInstanceOf(Serializable.class, itemWriter,
				"itemWriter must implement Serializable");
		itemProcessorSerializable = (Serializable) itemProcessor;
		itemWriterSerializable = (Serializable) itemWriter;
	}

}