Page Comparison

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The Event-Driven Consumer EIP allows an application to automatically consume messages as they become available. For more information, refer to http://www.eaipatterns.com/EventDrivenConsumer.html.

Figure 1: Event-Driven Consumer EIP 

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Before digging into implementation details, let's take a look at the relationship between the example scenario and the Event-Driven Consumer EIP by comparing their core components.

Environment setup

1. Download and install WSO2 ESB from http://wso2.com/products/enterprise-service-bus. For a list of prerequisites and step-by-step installation instructions, refer to Installation Guide in the WSO2 ESB documentation.
2. Start two sample Axis2 server. For instructions, refer to the section section Setting Up the ESB Samples - Starting the Axis2 server in the WSO2 ESB documentation.
3. Follow the steps below to create an event.
   
   • Start the ESB server and log into its management console UI (https: //localhost:9443/carbon ).
   • Select the Topics menu from the Main menu and then select the Add sub menu.
   • Enter EventConsumerTopic as the name for the topic, and then click Add Topic.
   • Click the newly created topic EventConsumerTopic in the topic browser tree and click Subscribe to create a static subscription.
     
   • Enter the value   http://localhost:9000/services/SimpleStockQuoteService in the Event Sink URL field and click Subscribe.
     

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<?xml version="1.0" encoding="UTF-8"?>
<definitions xmlns="http://ws.apache.org/ns/synapse">
   <sequence name="fault">
      <log level="full">
         <property name="MESSAGE" value="Executing default &#34;fault&#34; sequence"/>
         <property name="ERROR_CODE" expression="get-property('ERROR_CODE')"/>
         <property name="ERROR_MESSAGE" expression="get-property('ERROR_MESSAGE')"/>
      </log>
      <drop/>
   </sequence>
   <sequence name="main">
      <log/>
      <event topic="EventConsumerTopic"/>
   </sequence>
</definitions>

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