| 1 | /* |
| 2 | * Copyright 2006-2007 the original author or authors. |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package org.springframework.batch.item.jms; |
| 18 | |
| 19 | import javax.jms.Message; |
| 20 | |
| 21 | import org.apache.commons.logging.Log; |
| 22 | import org.apache.commons.logging.LogFactory; |
| 23 | import org.springframework.batch.item.ItemReader; |
| 24 | import org.springframework.beans.factory.InitializingBean; |
| 25 | import org.springframework.jms.core.JmsOperations; |
| 26 | import org.springframework.jms.core.JmsTemplate; |
| 27 | import org.springframework.util.Assert; |
| 28 | |
| 29 | /** |
| 30 | * An {@link ItemReader} for JMS using a {@link JmsTemplate}. The template |
| 31 | * should have a default destination, which will be used to provide items in |
| 32 | * {@link #read()}.<br/> |
| 33 | * <br/> |
| 34 | * |
| 35 | * The implementation is thread safe after its properties are set (normal |
| 36 | * singleton behavior). |
| 37 | * |
| 38 | * @author Dave Syer |
| 39 | * |
| 40 | */ |
| 41 | public class JmsItemReader<T> implements ItemReader<T>, InitializingBean { |
| 42 | |
| 43 | protected Log logger = LogFactory.getLog(getClass()); |
| 44 | |
| 45 | protected Class<? extends T> itemType; |
| 46 | |
| 47 | protected JmsOperations jmsTemplate; |
| 48 | |
| 49 | /** |
| 50 | * Setter for jms template. |
| 51 | * |
| 52 | * @param jmsTemplate a {@link JmsOperations} instance |
| 53 | */ |
| 54 | public void setJmsTemplate(JmsOperations jmsTemplate) { |
| 55 | this.jmsTemplate = jmsTemplate; |
| 56 | if (jmsTemplate instanceof JmsTemplate) { |
| 57 | JmsTemplate template = (JmsTemplate) jmsTemplate; |
| 58 | Assert.isTrue(template.getReceiveTimeout() != JmsTemplate.RECEIVE_TIMEOUT_INDEFINITE_WAIT, |
| 59 | "JmsTemplate must have a receive timeout!"); |
| 60 | Assert.isTrue(template.getDefaultDestination() != null || template.getDefaultDestinationName() != null, |
| 61 | "JmsTemplate must have a defaultDestination or defaultDestinationName!"); |
| 62 | } |
| 63 | } |
| 64 | |
| 65 | /** |
| 66 | * Set the expected type of incoming message payloads. Set this to |
| 67 | * {@link Message} to receive the raw underlying message. |
| 68 | * |
| 69 | * @param itemType the java class of the items to be delivered. Typically |
| 70 | * the same as the class parameter |
| 71 | * |
| 72 | * @throws IllegalStateException if the message payload is of the wrong |
| 73 | * type. |
| 74 | */ |
| 75 | public void setItemType(Class<? extends T> itemType) { |
| 76 | this.itemType = itemType; |
| 77 | } |
| 78 | |
| 79 | @SuppressWarnings("unchecked") |
| 80 | public T read() { |
| 81 | if (itemType != null && itemType.isAssignableFrom(Message.class)) { |
| 82 | return (T) jmsTemplate.receive(); |
| 83 | } |
| 84 | Object result = jmsTemplate.receiveAndConvert(); |
| 85 | if (itemType != null && result != null) { |
| 86 | Assert.state(itemType.isAssignableFrom(result.getClass()), |
| 87 | "Received message payload of wrong type: expected [" + itemType + "]"); |
| 88 | } |
| 89 | return (T) result; |
| 90 | } |
| 91 | |
| 92 | public void afterPropertiesSet() throws Exception { |
| 93 | Assert.notNull(this.jmsTemplate, "The 'jmsTemplate' is required."); |
| 94 | } |
| 95 | } |