CamelItemProcessor.java

/*
 * Copyright (c) 2016 Red Hat, Inc. and/or its affiliates.
 *
 * 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:
 * Cheng Fang - Initial API and implementation
 */

package org.jberet.camel;

import javax.annotation.PostConstruct;
import javax.batch.api.chunk.ItemProcessor;
import javax.inject.Named;

import _private.JBeretCamelLogger;
import org.apache.camel.ProducerTemplate;

/**
 * Implementation of {@code javax.batch.api.chunk.ItemProcessor} that processes
 * batch data using Apache Camel component.
 * <p>
 * The target Camel endpoint is configured through batch property
 * {@code endpoint} in job XML. For example,
 * <pre>
 * <job id="camelReaderTest" xmlns="http://xmlns.jcp.org/xml/ns/javaee" version="1.0">
 *   <step id="camelReaderTest.step1">
 *     <chunk>
 *       ... ...
 *       <processor ref="camelItemProcessor">
 *         <properties>
 *           <property name="endpoint" value="#{jobParameters['endpoint']}"/>
 *         </properties>
 *       </processor>
 *       ... ...
 * </pre>
 *
 * @see CamelItemReader
 * @see CamelItemWriter
 * @since 1.3.0
 */
@Named
public class CamelItemProcessor extends CamelArtifactBase implements ItemProcessor {

    /**
     * The Camel {@code ProducerTemplate} for forwarding the processing request
     * to Camel endpoint.
     */
    protected ProducerTemplate producerTemplate;

    @PostConstruct
    private void postConstruct() {
        init();
        if (producerTemplate == null) {
            producerTemplate = camelContext.createProducerTemplate();
        }
        JBeretCamelLogger.LOGGER.openProcessor(this, endpointUri, camelContext, producerTemplate);
    }

    /**
     * {@inheritDoc}
     * <p>
     *
     * This method forwards the current {@code item} to the configured Camel
     * endpoint for processing, and also retrieves the processing result.
     *
     * @param item the current item to be processed
     * @return processing result
     * @throws Exception
     */
    @Override
    public Object processItem(final Object item) throws Exception {
        return producerTemplate.requestBody(endpoint, item);
    }
}