ActiveMQ(AMQ)单浏览器AJAX多页面客户端的支持(clientId)

h_rain

    最近同事在使用AMQ进行消息通信时遇到了问题:
    在IE8中多个页面上访问AMQ的一个主题订阅的时候,多个页面中获得的消息其实是来自于同一个主题队列,导致页面状态逻辑错误.
    查找AMQ的官方文档后得知,在5.4.2之后的版本中,AMQ的AJAX客户端可以通过指定唯一的clientId,让多个页面在一个浏览器中能够访问相同订阅的不同队列,避免了之前版本中只判断JSESSIONID导致的客户端无法区分的问题.官方文档在这里:
    http://activemq.apache.org/ajax.html    但这里面实现的amq.js由于改动过大,无法与之前的接口兼容,所以并没有合并到官方主干源码中,只是以demo的形式额外存放.但实现上述功能的后端代码从5.4.2之后都被主干源码合并.
    所以,单纯使用最新版的AMQ,是无法得到这个AJAX多客户端的功能的,需要自己额外进行调整.
    今天上午解决了这个问题,稍稍修改了一下_amq.js文件,保证了与原接口的一致性,又增加了initClientId方法,可以方便的使用AMQ的AJAX多客户端功能了.  
    使用时,可以将这个_amq.js替换原activemq_web-x.x.x.jar中的文件,同时在调用页面中,进行最初uri赋值的时候,顺手调用一下amq.initClientId();就可以开启这个功能了.
    刚刚进行代码测试,初步通过,功能的正确性得到了初步验证.
    如果有同学遇到了相同的问题,希望能够帮忙进行测试调整.
    文章系本人原创，转载请注明出处和作者,本文原址在http://h-rain.iteye.com/blog/1387640
 
/** * 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. */// AMQ Ajax handler// This class provides the main API for using the Ajax features of AMQ. It// allows JMS messages to be sent and received from javascript when used// with the org.apache.activemq.web.MessageListenerServlet//var amq ={  // The URI of the MessageListenerServlet  uri: '/amq',  // Polling. Set to true (default) if waiting poll for messages is needed  poll: true,    // Poll delay. if set to positive integer, this is the time to wait in ms before  // sending the next poll after the last completes.  _pollDelay: 0,  _clientIdStr:'',  _first: true,  _pollEvent: function(first) {},  _handlers: new Array(),  _messages:0,  _messageQueue: '',  _queueMessages: 0,//init the clientId,default auto make as Date stringinitClientId:function(newId){if (newId)amq._clientIdStr="clientId="+newId;elseamq._clientIdStr="clientId="+(new Date()).getTime().toString();},//using clientId,whit separtor_makeClientIdStr:function(spChar){var SC=spChar||'';if (amq._clientIdStr=='')return '';return SC+amq._clientIdStr;},  _messageHandler: function(request)  {    try    {      if (request.status == 200)      {        var response = request.responseXML.getElementsByTagName("ajax-response");        if (response != null && response.length == 1)        {          for ( var i = 0 ; i < response[0].childNodes.length ; i++ )          {            var responseElement = response[0].childNodes;            // only process nodes of type element.....            if ( responseElement.nodeType != 1 )              continue;            var id   = responseElement.getAttribute('id');            var handler = amq._handlers[id];            if (handler!=null)            {              for (var j = 0; j < responseElement.childNodes.length; j++)              {                handler(responseElement.childNodes[j]);      }            }          }        }      }    }    catch(e)    {      alert(e);    }  },  startBatch: function()  {    amq._queueMessages++;  },  endBatch: function()  {    amq._queueMessages--;    if (amq._queueMessages==0 && amq._messages>0)    {      var body = amq._messageQueue;      amq._messageQueue='';      amq._messages=0;      amq._queueMessages++;      new Ajax.Request(amq.uri, { method: 'post', postBody: body+amq._makeClientIdStr('&'), onSuccess: amq.endBatch});    }  },  _pollHandler: function(request)  {    amq.startBatch();    try    {      amq._messageHandler(request);      amq._pollEvent(amq._first);      amq._first=false;    }    catch(e)    {        alert(e);    }    amq.endBatch();    if (amq._pollDelay>0)      setTimeout('amq._sendPoll()',amq._pollDelay);    else      amq._sendPoll();  },    _sendPoll: function(request)  {    new Ajax.Request(amq.uri, { method: 'get', parameters: amq._makeClientIdStr(),onSuccess: amq._pollHandler });  },  // Add a function that gets called on every poll response, after all received  // messages have been handled.  The poll handler is past a boolean that indicates  // if this is the first poll for the page.  addPollHandler : function(func)  {    var old = amq._pollEvent;    amq._pollEvent = function(first)    {      old(first);      func(first);    }  },  // Send a JMS message to a destination (eg topic://MY.TOPIC).  Message should be xml or encoded  // xml content.  sendMessage : function(destination,message)  {    amq._sendMessage(destination,message,'send');  },  // Listen on a channel or topic.   handler must be a function taking a message arguement  addListener : function(id,destination,handler)  {    amq._handlers[id]=handler;    amq._sendMessage(destination,id,'listen');  },  // remove Listener from channel or topic.  removeListener : function(id,destination)  {    amq._handlers[id]=null;    amq._sendMessage(destination,id,'unlisten');  },  _sendMessage : function(destination,message,type)  {    if (amq._queueMessages>0)    {      if (amq._messages==0)      {        amq._messageQueue='destination='+destination+'&message='+message+'&type='+type;      }      else      {        amq._messageQueue+='&d'+amq._messages+'='+destination+'&m'+amq._messages+'='+message+'&t'+amq._messages+'='+type;      }      amq._messages++;    }    else    {      amq.startBatch();      new Ajax.Request(amq.uri, { method: 'post', postBody: 'destination='+destination+'&message='+message+'&type='+type+amq._makeClientIdStr('&'), onSuccess: amq.endBatch});    }  },    _startPolling : function()  {   if (amq.poll)      new Ajax.Request(amq.uri, { method: 'get', parameters: 'timeout=10'+amq._makeClientIdStr('&'), onSuccess: amq._pollHandler });  }};Behaviour.addLoadEvent(amq._startPolling);function getKeyCode(ev){    var keyc;    if (window.event)        keyc=window.event.keyCode;    else        keyc=ev.keyCode;    return keyc;}