Add Scatter Gather mediator

[SanojPunchihewa]

Purpose

Add new mediator to clone the messages and aggregate the results.

Syntax

<scatter-gather parallel-execution=(true | false)>
<aggregation value-to-aggregate="expression" condition="expression" timeout="long"
    min-messages="expression" max-messages="expression"/>
    <target>
        <sequence>
        (mediator)+
        </sequence>
    </target>+
</scatter-gather>

Sample configuration

<scatter-gather parallel-execution="true">
    <aggregation value-to-aggregate="json-eval($)"/>
    <target>
        <sequence>
            <payloadFactory media-type="json" template-type="default">
                <format>{
                    "pet": {
                        "name": "pet1",
                        "type": "dog"
                    },
                    "status": "success"
                    }</format>
                <args>
                </args>
            </payloadFactory>
            <log category="INFO" level="custom">
                <property name="Message" value="==== DONE scatter target 1 ===="/>
            </log>
        </sequence>
    </target>
    <target>
        <sequence>
            <call>
                <endpoint>
                    <http method="get" uri-template="http://localhost:5454/api/pet2"/>
                </endpoint>
            </call>
            <log category="INFO" level="custom">
                <property name="Message" value="==== DONE scatter target 2 ===="/>
            </log>
        </sequence>
    </target>
</scatter-gather>