001 /** 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache License, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the License for the specific language governing permissions and 015 * limitations under the License. 016 */ 017 018 package org.apache.activemq.util.oxm; 019 020 import java.io.Serializable; 021 022 import javax.jms.JMSException; 023 import javax.jms.Message; 024 import javax.jms.MessageConsumer; 025 import javax.jms.MessageProducer; 026 import javax.jms.ObjectMessage; 027 import javax.jms.Session; 028 import javax.jms.TextMessage; 029 030 import org.apache.activemq.MessageTransformerSupport; 031 032 import com.thoughtworks.xstream.XStream; 033 import com.thoughtworks.xstream.io.HierarchicalStreamDriver; 034 035 /** 036 * Abstract class used as a base for implementing transformers from object to text messages (in XML/JSON format) 037 * and vice versa using. 038 * Supports plugging of custom marshallers 039 */ 040 public abstract class AbstractXMLMessageTransformer extends 041 MessageTransformerSupport { 042 043 protected MessageTransform transformType; 044 045 /** 046 * Defines the type of transformation. If XML (default), - producer 047 * transformation transforms from Object to XML. - consumer transformation 048 * transforms from XML to Object. If OBJECT, - producer transformation 049 * transforms from XML to Object. - consumer transformation transforms from 050 * Object to XML. If ADAPTIVE, - producer transformation transforms from 051 * Object to XML, or XML to Object depending on the type of the original 052 * message - consumer transformation transforms from XML to Object, or 053 * Object to XML depending on the type of the original message 054 */ 055 public enum MessageTransform { 056 XML, OBJECT, ADAPTIVE 057 }; 058 059 060 public AbstractXMLMessageTransformer() { 061 this(MessageTransform.XML); 062 } 063 064 public AbstractXMLMessageTransformer(MessageTransform transformType) { 065 this.transformType = transformType; 066 } 067 068 public Message consumerTransform(Session session, MessageConsumer consumer, Message message) throws JMSException { 069 switch (transformType) { 070 case XML: 071 return (message instanceof TextMessage) ? textToObject(session, (TextMessage)message) : message; 072 case OBJECT: 073 return (message instanceof ObjectMessage) ? objectToText(session, (ObjectMessage)message) : message; 074 case ADAPTIVE: 075 return (message instanceof TextMessage) ? textToObject(session, (TextMessage)message) : (message instanceof ObjectMessage) ? objectToText(session, (ObjectMessage)message) : message; 076 default: 077 } 078 return message; 079 } 080 081 public Message producerTransform(Session session, MessageProducer producer, Message message) throws JMSException { 082 switch (transformType) { 083 case XML: 084 return (message instanceof ObjectMessage) ? objectToText(session, (ObjectMessage)message) : message; 085 case OBJECT: 086 return (message instanceof TextMessage) ? textToObject(session, (TextMessage)message) : message; 087 case ADAPTIVE: 088 return (message instanceof TextMessage) ? textToObject(session, (TextMessage)message) : (message instanceof ObjectMessage) ? objectToText(session, (ObjectMessage)message) : message; 089 default: 090 } 091 return message; 092 } 093 094 public MessageTransform getTransformType() { 095 return transformType; 096 } 097 098 public void setTransformType(MessageTransform transformType) { 099 this.transformType = transformType; 100 } 101 102 /** 103 * Transforms an incoming XML encoded {@link TextMessage} to an 104 * {@link ObjectMessage} 105 * 106 * @param session - JMS session currently being used 107 * @param textMessage - text message to transform to object message 108 * @return ObjectMessage 109 * @throws JMSException 110 */ 111 protected ObjectMessage textToObject(Session session, TextMessage textMessage) throws JMSException { 112 Object object = unmarshall(session, textMessage); 113 if (object instanceof Serializable) { 114 ObjectMessage answer = session.createObjectMessage((Serializable)object); 115 copyProperties(textMessage, answer); 116 return answer; 117 } else { 118 throw new JMSException("Object is not serializable: " + object); 119 } 120 } 121 122 /** 123 * Transforms an incoming {@link ObjectMessage} to an XML encoded 124 * {@link TextMessage} 125 * 126 * @param session - JMS session currently being used 127 * @param objectMessage - object message to transform to text message 128 * @return XML encoded TextMessage 129 * @throws JMSException 130 */ 131 protected TextMessage objectToText(Session session, ObjectMessage objectMessage) throws JMSException { 132 TextMessage answer = session.createTextMessage(marshall(session, objectMessage)); 133 copyProperties(objectMessage, answer); 134 return answer; 135 } 136 137 /** 138 * Marshalls the Object in the {@link ObjectMessage} to a string using XML 139 * encoding 140 */ 141 protected abstract String marshall(Session session, ObjectMessage objectMessage) throws JMSException; 142 143 /** 144 * Unmarshalls the XML encoded message in the {@link TextMessage} to an 145 * Object 146 */ 147 protected abstract Object unmarshall(Session session, TextMessage textMessage) throws JMSException; 148 149 }