org.springframework.batch.item.jms.JmsItemReader Maven / Gradle / Ivy
/*
* Copyright 2006-2007 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
*
* https://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.item.jms;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.springframework.batch.item.ItemReader;
import org.springframework.beans.factory.InitializingBean;
import org.springframework.jms.core.JmsOperations;
import org.springframework.jms.core.JmsTemplate;
import org.springframework.util.Assert;
import javax.jms.Message;
/**
* An {@link ItemReader} for JMS using a {@link JmsTemplate}. The template
* should have a default destination, which will be used to provide items in
* {@link #read()}.
*
*
* The implementation is thread-safe after its properties are set (normal
* singleton behavior).
*
* @author Dave Syer
*
*/
public class JmsItemReader implements ItemReader, InitializingBean {
protected Log logger = LogFactory.getLog(getClass());
protected Class itemType;
protected JmsOperations jmsTemplate;
/**
* Setter for JMS template.
*
* @param jmsTemplate a {@link JmsOperations} instance
*/
public void setJmsTemplate(JmsOperations jmsTemplate) {
this.jmsTemplate = jmsTemplate;
if (jmsTemplate instanceof JmsTemplate) {
JmsTemplate template = (JmsTemplate) jmsTemplate;
Assert.isTrue(template.getReceiveTimeout() != JmsTemplate.RECEIVE_TIMEOUT_INDEFINITE_WAIT,
"JmsTemplate must have a receive timeout!");
Assert.isTrue(template.getDefaultDestination() != null || template.getDefaultDestinationName() != null,
"JmsTemplate must have a defaultDestination or defaultDestinationName!");
}
}
/**
* Set the expected type of incoming message payloads. Set this to
* {@link Message} to receive the raw underlying message.
*
* @param itemType the java class of the items to be delivered. Typically
* the same as the class parameter
*
* @throws IllegalStateException if the message payload is of the wrong
* type.
*/
public void setItemType(Class itemType) {
this.itemType = itemType;
}
@Override
@SuppressWarnings("unchecked")
public T read() {
if (itemType != null && itemType.isAssignableFrom(Message.class)) {
return (T) jmsTemplate.receive();
}
Object result = jmsTemplate.receiveAndConvert();
if (itemType != null && result != null) {
Assert.state(itemType.isAssignableFrom(result.getClass()),
"Received message payload of wrong type: expected [" + itemType + "]");
}
return (T) result;
}
@Override
public void afterPropertiesSet() throws Exception {
Assert.notNull(this.jmsTemplate, "The 'jmsTemplate' is required.");
}
}