Chapter 21. Compatibility Mode

For compatibility mode to work as expected, all endpoints need to be configured with the same cache manager, and need to talk to the same cache. If you’re using the brand new Red Hat Data Grid Server distribution , this is all done for you. If you’re in the mood to experiment with this in a standalone unit test, this class shows you how you can start multiple endpoints from a single class.

So, to get started using Red Hat Data Grid’s compatibility mode, it needs to be enabled, either via XML:

<local-cache>
   <compatibility/>
</local-cache>

<local-cache>
   <compatibility/>
</local-cache>

Or programmatically:

ConfigurationBuilder builder = ...
builder.compatibility().enable();

ConfigurationBuilder builder = ...
builder.compatibility().enable();

The key thing to remember about Red Hat Data Grid’s compatibility mode is that where possible, it tries to store data unmarshalling or deserializing it. It does so because the most common use case is for it to store Java objects and having Java objects stored in deserialized form means that they’re very easy to use from an embedded cache. With this in mind, it makes some assumptions. For example, if something is stored via Hot Rod, it’s most likely coming from the reference Hot Rod client, which is written in Java, and which uses a marshaller that keeps binary payloads very compact. So, when the Hot Rod operation reaches the compatibility layer, it will try to unmarshall it, by default using the same default marshaller used by the Java Hot Rod client, hence providing good out-of-the-box support for the majority of cases.

<local-cache>
   <compatibility marshaller="com.acme.CustomMarshaller"/>
</local-cache>

<local-cache>
   <compatibility marshaller="com.acme.CustomMarshaller"/>
</local-cache>

ConfigurationBuilder builder = ...
builder.compatibility().enable().marshaller(new com.acme.CustomMarshaller());

ConfigurationBuilder builder = ...
builder.compatibility().enable().marshaller(new com.acme.CustomMarshaller());

The best code examples available showing compatibility in action can be found in the Red Hat Data Grid Compatibility Mode testsuite, but more will be developed in the near future.