JCachePolicy in Camel 2

Question

I want to implement some content-caching on my Camel 2.23.2 routes. While researching I came across Camel's JCache component which, according to the documentation, should have a JCachePolicy that would:

"The JCachePolicy is an interceptor around a route that caches the "result of the route" - the message body - after the route is completed. If next time the route is called with a "similar" Exchange, the cached value is used on the Exchange instead of executing the route."

Which is basically exactly what I'm looking for. However, as it turns out this policy is only available in Camel 3.x and higher. So my question is, how might I recreate this functionality in Camel 2.23.2?

Answer 1

The solution was quite simple. In the Camel 3.x branch the policy package is available and in it are only two files. The actual policy and the processor.

As it turns out, pending more testing, these files work very well with little adjustment.

On the policy you need to change the method definition for the "wrap" and "beforeWrap" methods. These require the routeContext, not the Route. But moving from the RouteContext to the route is simple enough. On the processor, the main change is using the correct package for "DelegateAsyncProcessor" it extends.

With those changes everything seemingly works as documented. I used the ehcache spring boot starter in my pom without any further change to have it work with ehcache as it's cachemanager.

One other remark, when you want to use this, the model you want to cache needs to be serializable.