ActiveMQ example source code file (MessageServletSupport.java)

This example ActiveMQ source code file (MessageServletSupport.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

destination, destination, http, httpservletrequest, integer, io, ioexception, jmsexception, jmspriority, long, long, map, object, object, request, response, servlet, string, string, util

The ActiveMQ MessageServletSupport.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.web;

import java.io.BufferedReader;
import java.io.IOException;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import javax.jms.Destination;
import javax.jms.JMSException;
import javax.jms.TextMessage;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;

import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.ActiveMQQueue;
import org.apache.activemq.command.ActiveMQTopic;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

/**
 * A useful base class for any JMS related servlet; there are various ways to
 * map JMS operations to web requests so we put most of the common behaviour in
 * a reusable base class. This servlet can be configured with the following init
 * paramters
 * <dl>
 * <dt>topic
 * <dd>Set to 'true' if the servle should default to using topics rather than
 * channels</dd>
 * <dt>destination
 * <dd>The default destination to use if one is not specifiied
 * <dt>
 * <dd>
 * </dl>
 * 
 * 
 */
public abstract class MessageServletSupport extends HttpServlet {

    private static final transient Logger LOG = LoggerFactory.getLogger(MessageServletSupport.class);

    private boolean defaultTopicFlag = true;
    private Destination defaultDestination;
    private String destinationParameter = "destination";
    private String typeParameter = "type";
    private String bodyParameter = "body";
    private boolean defaultMessagePersistent = true;
    private int defaultMessagePriority = 5;
    private long defaultMessageTimeToLive;
    private String destinationOptions;

    public void init(ServletConfig servletConfig) throws ServletException {
        super.init(servletConfig);

        destinationOptions = servletConfig.getInitParameter("destinationOptions");

        String name = servletConfig.getInitParameter("topic");
        if (name != null) {
            defaultTopicFlag = asBoolean(name);
        }

        if (LOG.isDebugEnabled()) {
            LOG.debug("Defaulting to use topics: " + defaultTopicFlag);
        }
        name = servletConfig.getInitParameter("destination");
        if (name != null) {
            if (defaultTopicFlag) {
                defaultDestination = new ActiveMQTopic(name);
            } else {
                defaultDestination = new ActiveMQQueue(name);
            }
        }

        // lets check to see if there's a connection factory set
        WebClient.initContext(getServletContext());
    }

    public static boolean asBoolean(String param) {
        return asBoolean(param, false);
    }

    public static boolean asBoolean(String param, boolean defaultValue) {
        if (param == null) {
            return defaultValue;
        } else {
            return param.equalsIgnoreCase("true");
        }
    }

    protected void appendParametersToMessage(HttpServletRequest request, TextMessage message) throws JMSException {
        Map parameterMap = request.getParameterMap();
        if (parameterMap == null) {
            return;
        }
        Map parameters = new HashMap(parameterMap);
        String correlationID = asString(parameters.remove("JMSCorrelationID"));
        if (correlationID != null) {
            message.setJMSCorrelationID(correlationID);
        }
        Long expiration = asLong(parameters.remove("JMSExpiration"));
        if (expiration != null) {
            message.setJMSExpiration(expiration.longValue());
        }
        Destination replyTo = asDestination(parameters.remove("JMSReplyTo"));
        if (replyTo != null) {
            message.setJMSReplyTo(replyTo);
        }
        String type = (String)asString(parameters.remove("JMSType"));
        if (correlationID != null) {
            message.setJMSType(type);
        }

        for (Iterator iter = parameters.entrySet().iterator(); iter.hasNext();) {
            Map.Entry entry = (Map.Entry)iter.next();
            String name = (String)entry.getKey();
            if (!destinationParameter.equals(name) && !typeParameter.equals(name) && !bodyParameter.equals(name) && !"JMSDeliveryMode".equals(name) && !"JMSPriority".equals(name)
                && !"JMSTimeToLive".equals(name)) {
                Object value = entry.getValue();
                if (value instanceof Object[]) {
                    Object[] array = (Object[])value;
                    if (array.length == 1) {
                        value = array[0];
                    } else {
                        LOG.warn("Can't use property: " + name + " which is of type: " + value.getClass().getName() + " value");
                        value = null;
                        int size = array.length;
                        for (int i = 0; i < size; i++) {
                            LOG.debug("value[" + i + "] = " + array[i]);
                        }
                    }
                }
                if (value != null) {
                    message.setObjectProperty(name, value);
                }
            }
        }
    }

    protected long getSendTimeToLive(HttpServletRequest request) {
        String text = request.getParameter("JMSTimeToLive");
        if (text != null) {
            return asLong(text);
        }
        return defaultMessageTimeToLive;
    }

    protected int getSendPriority(HttpServletRequest request) {
        String text = request.getParameter("JMSPriority");
        if (text != null) {
            return asInt(text);
        }
        return defaultMessagePriority;
    }

    protected boolean isSendPersistent(HttpServletRequest request) {
        String text = request.getParameter("JMSDeliveryMode");
        if (text != null) {
            return text.trim().equalsIgnoreCase("persistent");
        }
        return defaultMessagePersistent;
    }

    protected boolean isSync(HttpServletRequest request) {
        String text = request.getParameter("sync");
        if (text != null) {
            return true;
        }
        return false;
    }    

    protected Destination asDestination(Object value) {
        if (value instanceof Destination) {
            return (Destination)value;
        }
        if (value instanceof String) {
            String text = (String)value;
            return ActiveMQDestination.createDestination(text, ActiveMQDestination.QUEUE_TYPE);
        }
        if (value instanceof String[]) {
            String text = ((String[])value)[0];
            if (text == null) {
                return null;
            }
            return ActiveMQDestination.createDestination(text, ActiveMQDestination.QUEUE_TYPE);
        }
        return null;
    }

    protected Integer asInteger(Object value) {
        if (value instanceof Integer) {
            return (Integer)value;
        }
        if (value instanceof String) {
            return Integer.valueOf((String)value);
        }
        if (value instanceof String[]) {
            return Integer.valueOf(((String[])value)[0]);
        }
        return null;
    }

    protected Long asLong(Object value) {
        if (value instanceof Long) {
            return (Long)value;
        }
        if (value instanceof String) {
            return Long.valueOf((String)value);
        }
        if (value instanceof String[]) {
            return Long.valueOf(((String[])value)[0]);
        }
        return null;
    }

    protected long asLong(String name) {
        return Long.parseLong(name);
    }

    protected int asInt(String name) {
        return Integer.parseInt(name);
    }

    protected String asString(Object value) {
        if (value instanceof String[]) {
            return ((String[])value)[0];
        }

        if (value != null) {
            return value.toString();
        }

        return null;
    }

    /**
     * @return the destination to use for the current request
     */
    protected Destination getDestination(WebClient client, HttpServletRequest request) throws JMSException {
        String destinationName = request.getParameter(destinationParameter);
        if (destinationName == null  || destinationName.equals("")) {
            if (defaultDestination == null) {
                return getDestinationFromURI(client, request);
            } else {
                return defaultDestination;
            }
        }

        return getDestination(client, request, destinationName);
    }

    /**
     * @return the destination to use for the current request using the relative
     *         URI from where this servlet was invoked as the destination name
     */
    protected Destination getDestinationFromURI(WebClient client, HttpServletRequest request) throws JMSException {
        String uri = request.getPathInfo();
        if (uri == null) {
            return null;
        }

        // replace URI separator with JMS destination separator
        if (uri.startsWith("/")) {
            uri = uri.substring(1);
            if (uri.length() == 0) {
                return null;
            }
        }

        uri = uri.replace('/', '.');
        LOG.debug("destination uri=" + uri);
        return getDestination(client, request, uri);
    }

    /**
     * @return the Destination object for the given destination name
     */
    protected Destination getDestination(WebClient client, HttpServletRequest request, String destinationName) throws JMSException {

        // TODO cache destinations ???

        boolean isTopic = defaultTopicFlag;
        if (destinationName.startsWith("topic://")) {
            isTopic = true;
        } else if (destinationName.startsWith("channel://") || destinationName.startsWith("queue://")) {
            isTopic = false;
        } else {
            isTopic = isTopic(request);
        }
        if (destinationName.indexOf("://") != -1) {
            destinationName = destinationName.substring(destinationName.indexOf("://") + 3);
        }

        if (destinationOptions != null) {
            destinationName += "?" + destinationOptions;
        }
        LOG.debug(destinationName + " (" + (isTopic ? "topic" : "queue") + ")");
        if (isTopic) {
            return client.getSession().createTopic(destinationName);
        } else {
            return client.getSession().createQueue(destinationName);
        }
    }

    /**
     * @return true if the current request is for a topic destination, else
     *         false if its for a queue
     */
    protected boolean isTopic(HttpServletRequest request) {
        String typeText = request.getParameter(typeParameter);
        if (typeText == null) {
            return defaultTopicFlag;
        }
        return typeText.equalsIgnoreCase("topic");
    }

    /**
     * @return the text that was posted to the servlet which is used as the body
     *         of the message to be sent
     */
    protected String getPostedMessageBody(HttpServletRequest request) throws IOException {
        String answer = request.getParameter(bodyParameter);
        if (answer == null && "text/xml".equals(request.getContentType())) {
            // lets read the message body instead
            BufferedReader reader = request.getReader();
            StringBuffer buffer = new StringBuffer();
            while (true) {
                String line = reader.readLine();
                if (line == null) {
                    break;
                }
                buffer.append(line);
                buffer.append("\n");
            }
            return buffer.toString();
        }
        return answer;
    }
    
    protected String getSelector(HttpServletRequest request) throws IOException {
    	return request.getHeader(WebClient.selectorName);
    }
}