ActiveMQ example source code file (JmsFrameTranslator.java)

This example ActiveMQ source code file (JmsFrameTranslator.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - ActiveMQ tags/keywords

activemqmapmessage, activemqobjectmessage, io, jmsexception, map, map, stompframe, stompframe, string, string, stringreader, stringwriter, utf-8, util, xstream, xstream

The ActiveMQ JmsFrameTranslator.java source code

/**
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You 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.apache.activemq.transport.stomp;

import java.io.IOException;
import java.io.Serializable;
import java.io.StringReader;
import java.io.StringWriter;
import java.util.HashMap;
import java.util.Map;

import javax.jms.JMSException;

import org.apache.activemq.advisory.AdvisorySupport;
import org.apache.activemq.broker.BrokerContext;
import org.apache.activemq.broker.BrokerContextAware;
import org.apache.activemq.command.ActiveMQMapMessage;
import org.apache.activemq.command.ActiveMQMessage;
import org.apache.activemq.command.ActiveMQObjectMessage;
import org.apache.activemq.command.DataStructure;
import org.apache.activemq.util.JettisonMappedXmlDriver;
import org.codehaus.jettison.mapped.Configuration;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;

import com.thoughtworks.xstream.XStream;
import com.thoughtworks.xstream.io.HierarchicalStreamReader;
import com.thoughtworks.xstream.io.HierarchicalStreamWriter;
import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;
import com.thoughtworks.xstream.io.xml.XppReader;

/**
 * Frame translator implementation that uses XStream to convert messages to and
 * from XML and JSON
 *
 * @author <a href="mailto:dejan@nighttale.net">Dejan Bosanac
 */
public class JmsFrameTranslator extends LegacyFrameTranslator implements
		BrokerContextAware {

	XStream xStream = null;
	BrokerContext brokerContext;

	public ActiveMQMessage convertFrame(ProtocolConverter converter,
			StompFrame command) throws JMSException, ProtocolException {
		Map headers = command.getHeaders();
		ActiveMQMessage msg;
		String transformation = (String) headers.get(Stomp.Headers.TRANSFORMATION);
		if (headers.containsKey(Stomp.Headers.CONTENT_LENGTH) || transformation.equals(Stomp.Transformations.JMS_BYTE.toString())) {
			msg = super.convertFrame(converter, command);
		} else {
			HierarchicalStreamReader in;

			try {
				String text = new String(command.getContent(), "UTF-8");
				switch (Stomp.Transformations.getValue(transformation)) {
				case JMS_OBJECT_XML:
					in = new XppReader(new StringReader(text));
					msg = createObjectMessage(in);
					break;
				case JMS_OBJECT_JSON:
					in = new JettisonMappedXmlDriver().createReader(new StringReader(text));
					msg = createObjectMessage(in);
					break;
				case JMS_MAP_XML:
					in = new XppReader(new StringReader(text));
					msg = createMapMessage(in);
					break;
				case JMS_MAP_JSON:
					in = new JettisonMappedXmlDriver().createReader(new StringReader(text));
					msg = createMapMessage(in);
					break;
				default:
					throw new Exception("Unkown transformation: " + transformation);
				}
			} catch (Throwable e) {
				command.getHeaders().put(Stomp.Headers.TRANSFORMATION_ERROR, e.getMessage());
				msg = super.convertFrame(converter, command);
			}
		}
		FrameTranslator.Helper.copyStandardHeadersFromFrameToMessage(converter, command, msg, this);
		return msg;
	}

	public StompFrame convertMessage(ProtocolConverter converter,
			ActiveMQMessage message) throws IOException, JMSException {
		if (message.getDataStructureType() == ActiveMQObjectMessage.DATA_STRUCTURE_TYPE) {
			StompFrame command = new StompFrame();
			command.setAction(Stomp.Responses.MESSAGE);
			Map<String, String> headers = new HashMap(25);
			command.setHeaders(headers);

			FrameTranslator.Helper.copyStandardHeadersFromMessageToFrame(
					converter, message, command, this);

            if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_XML.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_OBJECT_XML.toString());
            } else if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_JSON.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_OBJECT_JSON.toString());
            }

            ActiveMQObjectMessage msg = (ActiveMQObjectMessage) message.copy();
			command.setContent(marshall(msg.getObject(),
					headers.get(Stomp.Headers.TRANSFORMATION))
					.getBytes("UTF-8"));
			return command;

		} else if (message.getDataStructureType() == ActiveMQMapMessage.DATA_STRUCTURE_TYPE) {
			StompFrame command = new StompFrame();
			command.setAction(Stomp.Responses.MESSAGE);
			Map<String, String> headers = new HashMap(25);
			command.setHeaders(headers);

			FrameTranslator.Helper.copyStandardHeadersFromMessageToFrame(
					converter, message, command, this);

            if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_XML.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_MAP_XML.toString());
            } else if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_JSON.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_MAP_JSON.toString());
            }

			ActiveMQMapMessage msg = (ActiveMQMapMessage) message.copy();
			command.setContent(marshall((Serializable)msg.getContentMap(),
					headers.get(Stomp.Headers.TRANSFORMATION))
					.getBytes("UTF-8"));
			return command;
        } else if (message.getDataStructureType() == ActiveMQMessage.DATA_STRUCTURE_TYPE &&
                AdvisorySupport.ADIVSORY_MESSAGE_TYPE.equals(message.getType())) {

			StompFrame command = new StompFrame();
			command.setAction(Stomp.Responses.MESSAGE);
			Map<String, String> headers = new HashMap(25);
			command.setHeaders(headers);

            FrameTranslator.Helper.copyStandardHeadersFromMessageToFrame(
					converter, message, command, this);

            if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_XML.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_ADVISORY_XML.toString());
            } else if (headers.get(Stomp.Headers.TRANSFORMATION).equals(Stomp.Transformations.JMS_JSON.toString())) {
            	headers.put(Stomp.Headers.TRANSFORMATION, Stomp.Transformations.JMS_ADVISORY_JSON.toString());
            }

            String body = marshallAdvisory(message.getDataStructure(),
            		headers.get(Stomp.Headers.TRANSFORMATION));
            command.setContent(body.getBytes("UTF-8"));
            return command;
		} else {
			return super.convertMessage(converter, message);
		}
	}

	/**
	 * Marshalls the Object to a string using XML or JSON encoding
	 */
	protected String marshall(Serializable object, String transformation)
			throws JMSException {
		StringWriter buffer = new StringWriter();
		HierarchicalStreamWriter out;
		if (transformation.toLowerCase().endsWith("json")) {
			out = new JettisonMappedXmlDriver(new Configuration(), false).createWriter(buffer);
		} else {
			out = new PrettyPrintWriter(buffer);
		}
		getXStream().marshal(object, out);
		return buffer.toString();
	}

	protected ActiveMQObjectMessage createObjectMessage(HierarchicalStreamReader in) throws JMSException {
		ActiveMQObjectMessage objMsg = new ActiveMQObjectMessage();
		Object obj = getXStream().unmarshal(in);
		objMsg.setObject((Serializable) obj);
		return objMsg;
	}

	protected ActiveMQMapMessage createMapMessage(HierarchicalStreamReader in) throws JMSException {
		ActiveMQMapMessage mapMsg = new ActiveMQMapMessage();
		Map<String, Object> map = (Map)getXStream().unmarshal(in);
		for (String key : map.keySet()) {
			mapMsg.setObject(key, map.get(key));
		}
		return mapMsg;
	}

    protected String marshallAdvisory(final DataStructure ds, String transformation) {

		StringWriter buffer = new StringWriter();
		HierarchicalStreamWriter out;
		if (transformation.toLowerCase().endsWith("json")) {
			out = new JettisonMappedXmlDriver().createWriter(buffer);
		} else {
			out = new PrettyPrintWriter(buffer);
		}

		XStream xstream = getXStream();
        xstream.setMode(XStream.NO_REFERENCES);
        xstream.aliasPackage("", "org.apache.activemq.command");
		xstream.marshal(ds, out);
		return buffer.toString();
    }

	// Properties
	// -------------------------------------------------------------------------
	public XStream getXStream() {
		if (xStream == null) {
			xStream = createXStream();
		}
		return xStream;
	}

	public void setXStream(XStream xStream) {
		this.xStream = xStream;
	}

	// Implementation methods
	// -------------------------------------------------------------------------
	protected XStream createXStream() {
		XStream xstream = null;
		if (brokerContext != null) {
			Map<String, XStream> beans = brokerContext.getBeansOfType(XStream.class);
			for (XStream bean : beans.values()) {
			    if (bean != null) {
			        xstream = bean;
			        break;
			    }
			}
		}

		if (xstream == null) {
			xstream = new XStream();
		}
		return xstream;

	}

	public void setBrokerContext(BrokerContext brokerContext) {
		this.brokerContext = brokerContext;
	}

}