How to use ExtensibleEnvironment in Coherence Cache Configuration?

The ExtensibleEnvironment is an enhanced ConfigurableCacheFactory implementation that allows developers to independently create custom configurations and runtime extensions to Coherence. In other words, it allows you to include multiple configurations for your Coherence Grid. The steps that shall be followed to use it are as under:

1. Download the coherence-common jar from the Incubator site

2. Create the parent configuration file with the introduce:config pointing to other configuration that you want to include in the Coherence Grid configuration as below:

<?xml version="1.0"?>
<!DOCTYPE cache-config SYSTEM "cache-config.dtd">
<cache-config xmlns:introduce="class://com.oracle.coherence.environment.extensible.namespaces.IntroduceNamespaceContentHandler">
<introduce:config file="C:\Oracle\Coherence\Files\IncludeExample\IncludeConfiguration\include-config.xml"/>
<caching-scheme-mapping>
<cache-mapping>
<cache-name>*</cache-name>
<scheme-name>example-distributed</scheme-name>
</cache-mapping>
</caching-scheme-mapping>
<caching-schemes>
<!--
Distributed caching scheme.
-->
<distributed-scheme>
<scheme-name>example-distributed</scheme-name>
<service-name>DistributedCache</service-name>
<backing-map-scheme>
<local-scheme>
<scheme-ref>example-binary-backing-map</scheme-ref>
</local-scheme>
</backing-map-scheme>
<autostart>true</autostart>
</distributed-scheme>
</caching-schemes>
</cache-config>

Please note, it is very important to specify the namespace xmlns:introduce="class://com.oracle.coherence.environment.extensible.namespaces.IntroduceNamespaceContentHandler and also the file location needs to be complete path as otherwise it look in META-INF folder of the project.

3. Create other configuration files as mentioned below:

<?xml version="1.0"?>

<!DOCTYPE cache-config SYSTEM "cache-config.dtd">
<cache-config>
<caching-schemes>
<local-scheme>
<scheme-name>example-binary-backing-map</scheme-name>
<eviction-policy>HYBRID</eviction-policy>
<high-units>{back-size-limit 0}</high-units>
<unit-calculator>BINARY</unit-calculator>
<expiry-delay>{back-expiry 1h}</expiry-delay>
<cachestore-scheme></cachestore-scheme>
</local-scheme>
</caching-schemes>
</cache-config>

Now in the above example, we can see that parent configuration file has a reference to the "example-binary-backing-map" cache scheme which is available in the child configuration scheme and is included using the introduce element.