Sample 1: Simple Content-Based Routing (CBR) of Messages

 Objective: Introduction to simple content-based routing shows how a message could be made to pass through ESB using the Dumb Client mode, where ESB acts as a gateway to accept all messages and then performs mediation and routing based on message properties or content.

<definitions xmlns="http://ws.apache.org/ns/synapse">
    <sequence name="main">
        <in>
            <!-- filtering of messages with XPath and regex matches -->
            <filter source="get-property('To')" regex=".*/StockQuote.*">
                <send>
                    <endpoint>
                        <address uri="http://localhost:9000/services/SimpleStockQuoteService"/>
                    </endpoint>
                </send>
                <drop/>
            </filter>
            <send/>
        </in>
        <out>
            <send/>
        </out>
    </sequence>
</definitions>

Prerequisites:

• Start the Synapse configuration numbered 1: wso2esb-samples.sh -sn 1
• Start the Axis2 server and deploy the SimpleStockQuoteService if not already deployed.

Execute the Dumb Client as:

ant stockquote -Dtrpurl=http://localhost:8280/services/StockQuote

This time you will see ESB receiving a message for which ESB was set as the ultimate receiver of the message. ESB performs a match to the path/StockQuoteand based on the To EPR of the following location:

• http://localhost:8280/services/StockQuote

As the request matches the XPath expression of the Filter Mediator, the Filter Mediator's child mediators execute. It sends the message to a different endpoint as specified by the endpoint definition. The Drop Mediator terminates further processing of the current message in a configuration. During response processing, the filter condition fails and thus the implicit Send Mediator forwards the response back to the client.