java/modules/documentation/src/site/xdoc/userguide/samples/sample471.xml - synapse - Git at Google

 <?xml version="1.0" encoding="ISO-8859-1" ?>
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 <document>
     <properties>
         <title>Apache Synapse - Sample 471</title>
     </properties>
     <body>
         <section name="Sample 471: Introduction to the EJB Mediator II - Invoking Stateful Session Beans">
             <div class="xmlConf">&lt;definitions&gt;
     &lt;proxy name=&quot;BuyAllProxy&quot; transports=&quot;https http&quot; startOnLoad=&quot;true&quot; trace=&quot;disable&quot;&gt;
         &lt;target&gt;
             &lt;!-- Iterate over all items in the request and call addItem() on the ShoppingCart EJB for each item. --&gt;
             &lt;inSequence&gt;
                 &lt;property name=&quot;SESSION_ID&quot; expression=&quot;get-property(&apos;MessageID&apos;)&quot;/&gt;
                 &lt;iterate xmlns:m0=&quot;http://services.samples&quot; preservePayload=&quot;false&quot;
                          expression=&quot;//m0:buyItems/m0:items/m0:item&quot;&gt;
                     &lt;target&gt;
                         &lt;sequence&gt;
                             &lt;ejb class=&quot;samples.ejb.ShoppingCart&quot; beanstalk=&quot;demo&quot; method=&quot;addItem&quot; sessionId=&quot;{get-property(&apos;SESSION_ID&apos;)}&quot; jndiName=&quot;ShoppingCartBean/remote&quot;&gt;
                                 &lt;args&gt;
                                     &lt;arg value=&quot;{//m:item//m:id}&quot; xmlns:m=&quot;http://services.samples&quot;/&gt;
                                     &lt;arg value=&quot;{//m:item//m:quantity}&quot; xmlns:m=&quot;http://services.samples&quot;/&gt;
                                 &lt;/args&gt;
                             &lt;/ejb&gt;
                             &lt;sequence key=&quot;collector&quot;/&gt;
                         &lt;/sequence&gt;
                     &lt;/target&gt;
                 &lt;/iterate&gt;
             &lt;/inSequence&gt;
         &lt;/target&gt;
     &lt;/proxy&gt;

     &lt;!-- Prepare the response once all addItem() calls are finished. --&gt;
     &lt;sequence name=&quot;collector&quot;&gt;
         &lt;aggregate&gt;
             &lt;onComplete&gt;
                 &lt;ejb class=&quot;samples.ejb.ShoppingCart&quot; beanstalk=&quot;demo&quot; method=&quot;getItemCount&quot; sessionId=&quot;{get-property(&apos;SESSION_ID&apos;)}&quot; target=&quot;ITEM_COUNT&quot;/&gt;
                 &lt;ejb class=&quot;samples.ejb.ShoppingCart&quot; beanstalk=&quot;demo&quot; method=&quot;getTotal&quot; sessionId=&quot;{get-property(&apos;SESSION_ID&apos;)}&quot; target=&quot;TOTAL&quot; remove=&quot;true&quot;/&gt;
                 &lt;payloadFactory&gt;
                     &lt;format&gt;
                         &lt;buyAllResponse xmlns=&quot;&quot;&gt;
                             &lt;itemCount&gt;$1&lt;/itemCount&gt;
                             &lt;total&gt;$2&lt;/total&gt;
                         &lt;/buyAllResponse&gt;
                     &lt;/format&gt;
                     &lt;args&gt;
                         &lt;arg expression=&quot;get-property(&apos;ITEM_COUNT&apos;)&quot;/&gt;
                         &lt;arg expression=&quot;get-property(&apos;TOTAL&apos;)&quot;/&gt;
                     &lt;/args&gt;
                 &lt;/payloadFactory&gt;
                 &lt;respond/&gt;
             &lt;/onComplete&gt;
         &lt;/aggregate&gt;
     &lt;/sequence&gt;

 &lt;/definitions&gt;</div>
             <subsection name="Objective">
                 <p>
                     Demonstrate the usage of the EJB mediator for invoking EJB Stateful
                     Session Beans hosted on a remote EJB Container.
                 </p>
             </subsection>
             <subsection name="Pre-requisites">
                 <p>
                     <ul>
                         <li>
                             Follow steps 1 to 5 in <a href="sample470.html">Sample 470</a> to host the EJBs
                             in an EJB Container of your choice and to configure the <i>demo</i> beanstalk.
                         </li>
                         <li>
                             If the JNDI names assigned to the EJBs by your EJB Container differ from
                             the JNDI names specified in the sample 471 configuration file
                             (repository/conf/sample/synapse_sample_471.xml), edit the <i>jndiName</i>
                             attribute of all &lt; ejb /&gt; mediator invocations in the
                             <i>synapse_sample_471.xml</i> accordingly.
                         </li>
                         <li>
                             Start Synapse using the configuration numbered 471
                             (repository/conf/sample/synapse_sample_471.xml):
                             <div class="command">
                                 Unix/Linux: sh synapse.sh -sample 471<br/>
                                 Windows: synapse.bat -sample 471
                             </div>
                         </li>
                     </ul>
                 </p>
             </subsection>
             <subsection name="Executing the Client">
                 <p>
                     Send the following request to http://localhost:8280/services/BuyAllProxy
                     using a tool such at <a href="http://ws.apache.org/tcpmon/">TCPMon</a> or curl.
                 </p>
 <div class="xmlConf">&lt;soapenv:Envelope xmlns:soapenv=&quot;http://schemas.xmlsoap.org/soap/envelope/&quot;&gt;
   &lt;soapenv:Body&gt;
     &lt;buyItems xmlns=&quot;http://services.samples&quot;&gt;
         &lt;items&gt;
             &lt;item&gt;
                 &lt;id&gt;2150&lt;/id&gt;
                 &lt;quantity&gt;1&lt;/quantity&gt;
             &lt;/item&gt;
             &lt;item&gt;
                 &lt;id&gt;1189&lt;/id&gt;
                 &lt;quantity&gt;2&lt;/quantity&gt;
             &lt;/item&gt;
             &lt;item&gt;
                 &lt;id&gt;890&lt;/id&gt;
                 &lt;quantity&gt;4&lt;/quantity&gt;
             &lt;/item&gt;
         &lt;/items&gt;
     &lt;/buyItems&gt;
   &lt;/soapenv:Body&gt;
 &lt;/soapenv:Envelope&gt;</div>

                 <p>
                     Each instance of the <i>ShoppingCart</i> stateful session bean hosted on the remote EJB container
                     maintains a state which keeps track of the number and the total price of the items
                     added via its <i>addItem(String itemId, int count)</i> method. The <i>float getTotal()</i> and
                     <i>int getItemCount()</i> methods are used to retrieve this state.
                 </p>
                 <p>
                     When the <i>BuyAllProxy</i> receives the above request, it iterates over all &lt;item&gt; elements
                     in the request and calls the <i>addItem()</i> method on the <i>ShoppingCart</i> bean,
                     once per each &lt;item&gt;, using the EJB mediator. Since the <i>sessionId</i> used for these
                     invocations is actually the message ID, each request works on a new <i>ShoppingCart</i> instance
                     which is created at the first EJB mediator invocation in that request's flow.
                 </p>
                 <p>
                     When all <i>addItem()</i> method calls are finished, <i>getItemCount()</i> and <i>getTotal()</i> methods
                     are invoked on the same <i>ShoppingCart</i> instance within the <i>collector</i> sequence and
                     results are stored in two message context properties named <i>ITEM_COUNT</i> and <i>TOTAL</i>.
                     The last EJB call on the shopping cart sets the EJB mediator attribute <i>remove = "true"</i>
                     instructing the current stateful bean stub to be removed from the beanstalk. This is because the
                     same stateful bean instance will not be used again (each request uses a new bean instance). If the
                     user does not explicitly remove the stub using this attribute, it will be removed automatically
                     upon timeout as specified by the beanstalk configuration.
                 </p>
                 <p>
                     Finally, the PayloadFactory mediator is used to build the response message which is sent back to the
                     client.
                 </p>
                 <p>A sample response is shown below.</p>

 <div class="xmlConf">&lt;?xml version=&quot;1.0&quot; encoding=&quot;UTF-8&quot;?&gt;
 &lt;soapenv:Envelope xmlns:soapenv=&quot;http://schemas.xmlsoap.org/soap/envelope/&quot;&gt;
   &lt;soapenv:Body&gt;
     &lt;buyAllResponse&gt;
       &lt;itemCount&gt;7&lt;/itemCount&gt;
       &lt;total&gt;807.0&lt;/total&gt;
     &lt;/buyAllResponse&gt;
   &lt;/soapenv:Body&gt;
 &lt;/soapenv:Envelope&gt;</div>
             </subsection>
         </section>
         <p><a href="../samples.html">Back to Catalog</a></p>
     </body>
 </document>
	<?xml version="1.0" encoding="ISO-8859-1" ?>
	<!--
	~ 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.
	-->

	<document>
	<properties>
	<title>Apache Synapse - Sample 471</title>
	</properties>
	<body>
	<section name="Sample 471: Introduction to the EJB Mediator II - Invoking Stateful Session Beans">
	<div class="xmlConf"><definitions>
	<proxy name="BuyAllProxy" transports="https http" startOnLoad="true" trace="disable">
	<target>
	<!-- Iterate over all items in the request and call addItem() on the ShoppingCart EJB for each item. -->
	<inSequence>
	<property name="SESSION_ID" expression="get-property('MessageID')"/>
	<iterate xmlns:m0="http://services.samples" preservePayload="false"
	expression="//m0:buyItems/m0:items/m0:item">
	<target>
	<sequence>
	<ejb class="samples.ejb.ShoppingCart" beanstalk="demo" method="addItem" sessionId="{get-property('SESSION_ID')}" jndiName="ShoppingCartBean/remote">
	<args>
	<arg value="{//m:item//m:id}" xmlns:m="http://services.samples"/>
	<arg value="{//m:item//m:quantity}" xmlns:m="http://services.samples"/>
	</args>
	</ejb>
	<sequence key="collector"/>
	</sequence>
	</target>
	</iterate>
	</inSequence>
	</target>
	</proxy>

	<!-- Prepare the response once all addItem() calls are finished. -->
	<sequence name="collector">
	<aggregate>
	<onComplete>
	<ejb class="samples.ejb.ShoppingCart" beanstalk="demo" method="getItemCount" sessionId="{get-property('SESSION_ID')}" target="ITEM_COUNT"/>
	<ejb class="samples.ejb.ShoppingCart" beanstalk="demo" method="getTotal" sessionId="{get-property('SESSION_ID')}" target="TOTAL" remove="true"/>
	<payloadFactory>
	<format>
	<buyAllResponse xmlns="">
	<itemCount>$1</itemCount>
	<total>$2</total>
	</buyAllResponse>
	</format>
	<args>
	<arg expression="get-property('ITEM_COUNT')"/>
	<arg expression="get-property('TOTAL')"/>
	</args>
	</payloadFactory>
	<respond/>
	</onComplete>
	</aggregate>
	</sequence>

	</definitions></div>
	<subsection name="Objective">
	<p>
	Demonstrate the usage of the EJB mediator for invoking EJB Stateful
	Session Beans hosted on a remote EJB Container.
	</p>
	</subsection>
	<subsection name="Pre-requisites">
	<p>
	<ul>
	<li>
	Follow steps 1 to 5 in <a href="sample470.html">Sample 470</a> to host the EJBs
	in an EJB Container of your choice and to configure the <i>demo</i> beanstalk.
	</li>
	<li>
	If the JNDI names assigned to the EJBs by your EJB Container differ from
	the JNDI names specified in the sample 471 configuration file
	(repository/conf/sample/synapse_sample_471.xml), edit the <i>jndiName</i>
	attribute of all < ejb /> mediator invocations in the
	<i>synapse_sample_471.xml</i> accordingly.
	</li>
	<li>
	Start Synapse using the configuration numbered 471
	(repository/conf/sample/synapse_sample_471.xml):
	<div class="command">
	Unix/Linux: sh synapse.sh -sample 471<br/>
	Windows: synapse.bat -sample 471
	</div>
	</li>
	</ul>
	</p>
	</subsection>
	<subsection name="Executing the Client">
	<p>
	Send the following request to http://localhost:8280/services/BuyAllProxy
	using a tool such at <a href="http://ws.apache.org/tcpmon/">TCPMon</a> or curl.
	</p>
	<div class="xmlConf"><soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
	<soapenv:Body>
	<buyItems xmlns="http://services.samples">
	<items>
	<item>
	<id>2150</id>
	<quantity>1</quantity>
	</item>
	<item>
	<id>1189</id>
	<quantity>2</quantity>
	</item>
	<item>
	<id>890</id>
	<quantity>4</quantity>
	</item>
	</items>
	</buyItems>
	</soapenv:Body>
	</soapenv:Envelope></div>

	<p>
	Each instance of the <i>ShoppingCart</i> stateful session bean hosted on the remote EJB container
	maintains a state which keeps track of the number and the total price of the items
	added via its <i>addItem(String itemId, int count)</i> method. The <i>float getTotal()</i> and
	<i>int getItemCount()</i> methods are used to retrieve this state.
	</p>
	<p>
	When the <i>BuyAllProxy</i> receives the above request, it iterates over all <item> elements
	in the request and calls the <i>addItem()</i> method on the <i>ShoppingCart</i> bean,
	once per each <item>, using the EJB mediator. Since the <i>sessionId</i> used for these
	invocations is actually the message ID, each request works on a new <i>ShoppingCart</i> instance
	which is created at the first EJB mediator invocation in that request's flow.
	</p>
	<p>
	When all <i>addItem()</i> method calls are finished, <i>getItemCount()</i> and <i>getTotal()</i> methods
	are invoked on the same <i>ShoppingCart</i> instance within the <i>collector</i> sequence and
	results are stored in two message context properties named <i>ITEM_COUNT</i> and <i>TOTAL</i>.
	The last EJB call on the shopping cart sets the EJB mediator attribute <i>remove = "true"</i>
	instructing the current stateful bean stub to be removed from the beanstalk. This is because the
	same stateful bean instance will not be used again (each request uses a new bean instance). If the
	user does not explicitly remove the stub using this attribute, it will be removed automatically
	upon timeout as specified by the beanstalk configuration.
	</p>
	<p>
	Finally, the PayloadFactory mediator is used to build the response message which is sent back to the
	client.
	</p>
	<p>A sample response is shown below.</p>

	<div class="xmlConf"><?xml version="1.0" encoding="UTF-8"?>
	<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/">
	<soapenv:Body>
	<buyAllResponse>
	<itemCount>7</itemCount>
	<total>807.0</total>
	</buyAllResponse>
	</soapenv:Body>
	</soapenv:Envelope></div>
	</subsection>
	</section>
	<p><a href="../samples.html">Back to Catalog</a></p>
	</body>
	</document>