Package org.apache.activemq.web

Class MessageServlet

java.lang.Object

javax.servlet.GenericServlet

javax.servlet.http.HttpServlet

org.apache.activemq.web.MessageServletSupport

org.apache.activemq.web.MessageServlet

All Implemented Interfaces:

Serializable, Servlet, ServletConfig

public class MessageServlet
extends MessageServletSupport

A servlet for sending and receiving messages to/from JMS destinations using HTTP POST for sending and HTTP GET for receiving.

You can specify the destination and whether it is a topic or queue via configuration details on the servlet or as request parameters.

For reading messages you can specify a readTimeout parameter to determine how long the servlet should block for. One thing to keep in mind with this solution - due to the nature of REST, there will always be a chance of losing messages. Consider what happens when a message is retrieved from the broker but the web call is interrupted before the client receives the message in the response - the message is lost.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
MessageServlet()

Method Summary

Modifier and Type	Method	Description
protected void	closeConsumerOnOneShot(HttpServletRequest request, WebClient client, Destination dest)	Close the consumer if one-shot mode is used on the given request.
protected void	doDelete(HttpServletRequest request, HttpServletResponse response)	Supports a HTTP DELETE to be equivalent of consuming a single message from a queue
protected void	doGet(HttpServletRequest request, HttpServletResponse response)	Supports a HTTP DELETE to be equivalent of consuming a single message from a queue
protected void	doMessages(HttpServletRequest request, HttpServletResponse response)	Reads a message from a destination up to some specific timeout period
protected void	doPost(HttpServletRequest request, HttpServletResponse response)	Sends a message to a destination
protected String	getContentType(HttpServletRequest request)
protected long	getReadDeadline(HttpServletRequest request)
WebClient	getWebClient(HttpServletRequest request)
protected void	handleContinuation(HttpServletRequest request, HttpServletResponse response, WebClient client, Destination destination, MessageAvailableConsumer consumer, long deadline)
void	init()
protected boolean	isXmlContent(Message message)
protected void	setResponseHeaders(HttpServletResponse response, Message message)
protected void	writeMessageResponse(PrintWriter writer, Message message)
protected void	writeResponse(HttpServletRequest request, HttpServletResponse response, Message message)

Methods inherited from class org.apache.activemq.web.MessageServletSupport

appendParametersToMessage, asBoolean, asBoolean, asDestination, asInt, asInteger, asLong, asLong, asString, getDestination, getDestination, getDestinationFromURI, getPostedMessageBody, getSelector, getSendPriority, getSendTimeToLive, init, isSendPersistent, isSync, isTopic

Methods inherited from class javax.servlet.http.HttpServlet

doHead, doOptions, doPut, doTrace, getLastModified, service, service

Methods inherited from class javax.servlet.GenericServlet

destroy, getInitParameter, getInitParameterNames, getServletConfig, getServletContext, getServletInfo, getServletName, log, log

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

MessageServlet

public MessageServlet()

Method Detail

init

public void init()
          throws ServletException

Overrides:

init in class GenericServlet

Throws:

ServletException

doPost

protected void doPost(HttpServletRequest request,
                      HttpServletResponse response)
               throws ServletException,
                      IOException

Sends a message to a destination

Overrides:

doPost in class HttpServlet

Parameters:

request -

response -

Throws:

ServletException

IOException

doDelete

protected void doDelete(HttpServletRequest request,
                        HttpServletResponse response)
                 throws ServletException,
                        IOException

Supports a HTTP DELETE to be equivalent of consuming a single message from a queue

Overrides:

doDelete in class HttpServlet

Throws:

ServletException

IOException

doGet

protected void doGet(HttpServletRequest request,
                     HttpServletResponse response)
              throws ServletException,
                     IOException

Supports a HTTP DELETE to be equivalent of consuming a single message from a queue

Overrides:

doGet in class HttpServlet

Throws:

ServletException

IOException

doMessages

protected void doMessages(HttpServletRequest request,
                          HttpServletResponse response)
                   throws ServletException,
                          IOException

Reads a message from a destination up to some specific timeout period

Parameters:

request -

response -

Throws:

ServletException

IOException

handleContinuation

protected void handleContinuation(HttpServletRequest request,
                                  HttpServletResponse response,
                                  WebClient client,
                                  Destination destination,
                                  MessageAvailableConsumer consumer,
                                  long deadline)

writeResponse

protected void writeResponse(HttpServletRequest request,
                             HttpServletResponse response,
                             Message message)
                      throws IOException,
                             JMSException

Throws:

IOException

JMSException

writeMessageResponse

protected void writeMessageResponse(PrintWriter writer,
                                    Message message)
                             throws JMSException,
                                    IOException

Throws:

JMSException

IOException

isXmlContent

protected boolean isXmlContent(Message message)
                        throws JMSException

Throws:

JMSException

getWebClient

public WebClient getWebClient(HttpServletRequest request)

getContentType

protected String getContentType(HttpServletRequest request)

setResponseHeaders

protected void setResponseHeaders(HttpServletResponse response,
                                  Message message)
                           throws JMSException

Throws:

JMSException

getReadDeadline

protected long getReadDeadline(HttpServletRequest request)

Returns:

the timeout value for read requests which is always >= 0 and <= maximumReadTimeout to avoid DoS attacks

closeConsumerOnOneShot

protected void closeConsumerOnOneShot(HttpServletRequest request,
                                      WebClient client,
                                      Destination dest)

Close the consumer if one-shot mode is used on the given request.