Sample 701: Introduction to Message Sampling Processor

Note that WSO2 EI is shipped with the following changes to what is mentioned in this documentation:

<PRODUCT_HOME>/repository/samples/ directory that includes all Integration profile samples is changed to <EI_HOME>/samples/service-bus/.
<PRODUCT_HOME>/repository/samples/resources/ directory that includes all artifacts related to the Integration profile samples is changed to <EI_HOME>/samples/service-bus/resources/.

Objective: Introduction to Message Sampling Processor.

            <!-- Introduction to  Message Sampling Processor -->

            <definitions xmlns="http://ws.apache.org/ns/synapse">
                <sequence name="send_seq">
                    <send>
                        <endpoint>
                            <address uri="http://localhost:9000/services/SimpleStockQuoteService">
                                <suspendOnFailure>
                                <errorCodes>-1</errorCodes>
                                <progressionFactor>1.0</progressionFactor>
                                </suspendOnFailure>
                            </address>
                        </endpoint>
                    </send>
                </sequence>
                <sequence name="main">
                    <in>
                        <log level="full"/>
                        <property name="FORCE_SC_ACCEPTED" value="true" scope="axis2"/>
                        <property name="OUT_ONLY" value="true"/>
                        <store messageStore="MyStore"/>
                    </in>
                    <out/>
                    <description>The main sequence for the message mediation</description>
                </sequence>
                <messageStore name="MyStore"/>
                <messageProcessor
                     class="org.apache.synapse.message.processor.impl.sampler.SamplingProcessor"
                     name="SamplingProcessor" messageStore="MyStore">
                    <parameter name="interval">20000</parameter>
                    <parameter name="sequence">send_seq</parameter>
                </messageProcessor>
            </definitions>

Prerequisites:

Create the above configuration and deploy it in the WSO2 EI profile, see Working with WSO2 Integration Studio.
Start the SimpleStockQuoteService if its not already started

To Execute the Client few times:

ant stockquote -Daddurl=http://localhost:9000/services/SimpleStockQuoteService -Dtrpurl=http://localhost:8280/ -Dmode=placeorder

When you execute the client, the message will be dispatched to the main sequence. In the Main sequence, store mediator will store the placeOrder request message in the "MyStore" Message Store. Message Processor will consume the messages, and forward to the "send_seq" sequence in configured rate. You will observe that the service invocation rate is not changing when we increase the rate of client executions.