One thing that has been difficult to solve in Interlok is the ability to execute two services in parallel against a message.
With the use of shared services and the pooling-message-splitter-service we can now do exactly that.
More specifically we can use dynamic-shared-service, the split-by-metadata splitter and a metadata expressions, to execute a list of services is parallel.
<shared-components>
<services>
<service-list>
<unique-id>action1</unique-id>
<services>
<!-- ... -->
</services>
</service-list>
<service-list>
<unique-id>action1</unique-id>
<services>
<!-- ... -->
</services>
</service-list>
</services>
</shared-component>
<!-- ... -->
<services>
<add-metadata-service>
<key-value-pair>
<key>actions</key>
<value>action1,action2</value>
</key-value-pair>
</add-metadata-service>
<pooling-message-splitter-service>
<max-threads>2</max-threads>
<splitter class="split-by-metadata">
<metadata-key>actions</metadata-key>
<split-metadata-key>action</split-metadata-key>
<separator>,</separator>
</splitter>
<service class="service-list">
<services>
<dynamic-shared-service>
<lookup-name>%message{action}</lookup-name>
</dynamic-shared-service>
</services>
</service>
</pooling-message-splitter-service>
</services>
A real world example could be a using pooling-split-join-service where the shared services made calls to different APIs then using an aggregator like json-array-aggregator to produce the combined payload.