/*
* Copyright 2002-2011 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.
*/
package org.springframework.jms.support.converter;
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.StringWriter;
import java.io.UnsupportedEncodingException;
import java.util.HashMap;
import java.util.Map;
import javax.jms.BytesMessage;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.xml.transform.Result;
import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.type.TypeFactory;
import org.codehaus.jackson.type.JavaType;
import org.springframework.oxm.Marshaller;
import org.springframework.util.Assert;
import org.springframework.util.ClassUtils;
/**
* Message converter that uses the Jackson library to convert messages to and from JSON.
* Maps an object to a {@link BytesMessage}, or to a {@link TextMessage} if the
* {@link #setTargetType targetType} is set to {@link MessageType#TEXT}.
* Converts from a {@link TextMessage} or {@link BytesMessage} to an object.
*
* @author Mark Pollack
* @author Dave Syer
* @author Juergen Hoeller
* @since 3.1
*/
public class MappingJacksonMessageConverter implements MessageConverter {
/**
* The default encoding used for writing to text messages: UTF-8.
*/
public static final String DEFAULT_ENCODING = "UTF-8";
private ObjectMapper objectMapper = new ObjectMapper();
private MessageType targetType = MessageType.BYTES;
private String encoding = DEFAULT_ENCODING;
private String encodingPropertyName;
private String typeIdPropertyName;
private Map<String, Class<?>> idClassMappings = new HashMap<String, Class<?>>();
private Map<Class<?>, String> classIdMappings = new HashMap<Class<?>, String>();
/**
* Specify the {@link ObjectMapper} to use instead of using the default.
*/
public void setObjectMapper(ObjectMapper objectMapper) {
Assert.notNull(objectMapper, "ObjectMapper must not be null");
this.objectMapper = objectMapper;
}
/**
* Specify whether {@link #toMessage(Object, Session)} should marshal to a
* {@link BytesMessage} or a {@link TextMessage}.
* <p>The default is {@link MessageType#BYTES}, i.e. this converter marshals to
* a {@link BytesMessage}. Note that the default version of this converter
* supports {@link MessageType#BYTES} and {@link MessageType#TEXT} only.
* @see MessageType#BYTES
* @see MessageType#TEXT
*/
public void setTargetType(MessageType targetType) {
Assert.notNull(targetType, "MessageType must not be null");
this.targetType = targetType;
}
/**
* Specify the encoding to use when converting to and from text-based
* message body content. The default encoding will be "UTF-8".
* <p>When reading from a a text-based message, an encoding may have been
* suggested through a special JMS property which will then be preferred
* over the encoding set on this MessageConverter instance.
* @see #setEncodingPropertyName
*/
public void setEncoding(String encoding) {
this.encoding = encoding;
}
/**
* Specify the name of the JMS message property that carries the encoding from
* bytes to String and back is BytesMessage is used during the conversion process.
* <p>Default is none. Setting this property is optional; if not set, UTF-8 will
* be used for decoding any incoming bytes message.
* @see #setEncoding
*/
public void setEncodingPropertyName(String encodingPropertyName) {
this.encodingPropertyName = encodingPropertyName;
}
/**
* Specify the name of the JMS message property that carries the type id for the
* contained object: either a mapped id value or a raw Java class name.
* <p>Default is none. <b>NOTE: This property needs to be set in order to allow
* for converting from an incoming message to a Java object.</b>
* @see #setTypeIdMappings
*/
public void setTypeIdPropertyName(String typeIdPropertyName) {
this.typeIdPropertyName = typeIdPropertyName;
}
/**
* Specify mappings from type ids to Java classes, if desired.
* This allows for synthetic ids in the type id message property,
* instead of transferring Java class names.
* <p>Default is no custom mappings, i.e. transferring raw Java class names.
* @param typeIdMappings a Map with type id values as keys and Java classes as values
*/
public void setTypeIdMappings(Map<String, Class<?>> typeIdMappings) {
this.idClassMappings = new HashMap<String, Class<?>>();
for (Map.Entry<String, Class<?>> entry : typeIdMappings.entrySet()) {
String id = entry.getKey();
Class<?> clazz = entry.getValue();
this.idClassMappings.put(id, clazz);
this.classIdMappings.put(clazz, id);
}
}
public Message toMessage(Object object, Session session) throws JMSException, MessageConversionException {
Message message;
try {
switch (this.targetType) {
case TEXT:
message = mapToTextMessage(object, session, this.objectMapper);
break;
case BYTES:
message = mapToBytesMessage(object, session, this.objectMapper);
break;
default:
message = mapToMessage(object, session, this.objectMapper, this.targetType);
}
}
catch (IOException ex) {
throw new MessageConversionException("Could not map JSON object [" + object + "]", ex);
}
setTypeIdOnMessage(object, message);
return message;
}
public Object fromMessage(Message message) throws JMSException, MessageConversionException {
try {
JavaType targetJavaType = getJavaTypeForMessage(message);
return convertToObject(message, targetJavaType);
}
catch (IOException ex) {
throw new MessageConversionException("Failed to convert JSON message content", ex);
}
}
/**
* Map the given object to a {@link TextMessage}.
* @param object the object to be mapped
* @param session current JMS session
* @param objectMapper the mapper to use
* @return the resulting message
* @throws JMSException if thrown by JMS methods
* @throws IOException in case of I/O errors
* @see Session#createBytesMessage
* @see Marshaller#marshal(Object, Result)
*/
protected TextMessage mapToTextMessage(Object object, Session session, ObjectMapper objectMapper)
throws JMSException, IOException {
StringWriter writer = new StringWriter();
objectMapper.writeValue(writer, object);
return session.createTextMessage(writer.toString());
}
/**
* Map the given object to a {@link BytesMessage}.
* @param object the object to be mapped
* @param session current JMS session
* @param objectMapper the mapper to use
* @return the resulting message
* @throws JMSException if thrown by JMS methods
* @throws IOException in case of I/O errors
* @see Session#createBytesMessage
* @see Marshaller#marshal(Object, Result)
*/
protected BytesMessage mapToBytesMessage(Object object, Session session, ObjectMapper objectMapper)
throws JMSException, IOException {
ByteArrayOutputStream bos = new ByteArrayOutputStream();
OutputStreamWriter writer = new OutputStreamWriter(bos, this.encoding);
objectMapper.writeValue(writer, object);
BytesMessage message = session.createBytesMessage();
message.writeBytes(bos.toByteArray());
if (this.encodingPropertyName != null) {
message.setStringProperty(this.encodingPropertyName, this.encoding);
}
return message;
}
/**
* Template method that allows for custom message mapping.
* Invoked when {@link #setTargetType} is not {@link MessageType#TEXT} or
* {@link MessageType#BYTES}.
* <p>The default implementation throws an {@link IllegalArgumentException}.
* @param object the object to marshal
* @param session the JMS Session
* @param objectMapper the mapper to use
* @param targetType the target message type (other than TEXT or BYTES)
* @return the resulting message
* @throws JMSException if thrown by JMS methods
* @throws IOException in case of I/O errors
*/
protected Message mapToMessage(Object object, Session session, ObjectMapper objectMapper, MessageType targetType)
throws JMSException, IOException {
throw new IllegalArgumentException("Unsupported message type [" + targetType +
"]. MappingJacksonMessageConverter by default only supports TextMessages and BytesMessages.");
}
/**
* Set a type id for the given payload object on the given JMS Message.
* <p>The default implementation consults the configured type id mapping and
* sets the resulting value (either a mapped id or the raw Java class name)
* into the configured type id message property.
* @param object the payload object to set a type id for
* @param message the JMS Message to set the type id on
* @throws JMSException if thrown by JMS methods
* @see #getJavaTypeForMessage(javax.jms.Message)
* @see #setTypeIdPropertyName(String)
* @see #setTypeIdMappings(java.util.Map)
*/
protected void setTypeIdOnMessage(Object object, Message message) throws JMSException {
if (this.typeIdPropertyName != null) {
String typeId = this.classIdMappings.get(object.getClass());
if (typeId == null) {
typeId = object.getClass().getName();
}
message.setStringProperty(this.typeIdPropertyName, typeId);
}
}
/**
* Convenience method to dispatch to converters for individual message types.
*/
private Object convertToObject(Message message, JavaType targetJavaType) throws JMSException, IOException {
if (message instanceof TextMessage) {
return convertFromTextMessage((TextMessage) message, targetJavaType);
}
else if (message instanceof BytesMessage) {
return convertFromBytesMessage((BytesMessage) message, targetJavaType);
}
else {
return convertFromMessage(message, targetJavaType);
}
}
/**
* Convert a TextMessage to a Java Object with the specified type.
* @param message the input message
* @param targetJavaType the target type
* @return the message converted to an object
* @throws JMSException if thrown by JMS
* @throws IOException in case of I/O errors
*/
protected Object convertFromTextMessage(TextMessage message, JavaType targetJavaType)
throws JMSException, IOException {
String body = message.getText();
return this.objectMapper.readValue(body, targetJavaType);
}
/**
* Convert a BytesMessage to a Java Object with the specified type.
* @param message the input message
* @param targetJavaType the target type
* @return the message converted to an object
* @throws JMSException if thrown by JMS
* @throws IOException in case of I/O errors
*/
protected Object convertFromBytesMessage(BytesMessage message, JavaType targetJavaType)
throws JMSException, IOException {
String encoding = this.encoding;
if (this.encodingPropertyName != null && message.propertyExists(this.encodingPropertyName)) {
encoding = message.getStringProperty(this.encodingPropertyName);
}
byte[] bytes = new byte[(int) message.getBodyLength()];
message.readBytes(bytes);
try {
String body = new String(bytes, encoding);
return this.objectMapper.readValue(body, targetJavaType);
}
catch (UnsupportedEncodingException ex) {
throw new MessageConversionException("Cannot convert bytes to String", ex);
}
}
/**
* Template method that allows for custom message mapping.
* Invoked when {@link #setTargetType} is not {@link MessageType#TEXT} or
* {@link MessageType#BYTES}.
* <p>The default implementation throws an {@link IllegalArgumentException}.
* @param message the input message
* @param targetJavaType the target type
* @return the message converted to an object
* @throws JMSException if thrown by JMS
* @throws IOException in case of I/O errors
*/
protected Object convertFromMessage(Message message, JavaType targetJavaType)
throws JMSException, IOException {
throw new IllegalArgumentException("Unsupported message type [" + message.getClass() +
"]. MappingJacksonMessageConverter by default only supports TextMessages and BytesMessages.");
}
/**
* Determine a Jackson JavaType for the given JMS Message,
* typically parsing a type id message property.
* <p>The default implementation parses the configured type id property name
* and consults the configured type id mapping. This can be overridden with
* a different strategy, e.g. doing some heuristics based on message origin.
* @param object the payload object to set a type id for
* @param message the JMS Message to set the type id on
* @throws JMSException if thrown by JMS methods
* @see #setTypeIdOnMessage(Object, javax.jms.Message)
* @see #setTypeIdPropertyName(String)
* @see #setTypeIdMappings(java.util.Map)
*/
protected JavaType getJavaTypeForMessage(Message message) throws JMSException {
String typeId = message.getStringProperty(this.typeIdPropertyName);
if (typeId == null) {
throw new MessageConversionException("Could not find type id property [" + this.typeIdPropertyName + "]");
}
Class mappedClass = this.idClassMappings.get(typeId);
if (mappedClass != null) {
return TypeFactory.type(mappedClass);
}
try {
return TypeFactory.type(ClassUtils.forName(typeId, getClass().getClassLoader()));
}
catch (Throwable ex) {
throw new MessageConversionException("Failed to resolve type id [" + typeId + "]", ex);
}
}
}