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[cdi-dev] It is beyond time to fix interception on self invocation

Hi,


one of the most unintuitive and tripping things in CDI is invoking internal methods inside a CDI bean and having interceptors on this methods. Even after several years as a JavaEE/MP developer I still occasionaly forget about this fact and waste hours trying to figure out why my interceptor is not triggering.

It is almost every day that I encounter a need to put a metrics @Timed or a fault tolerance @Retry, a @Transactional, logging interceptor etc. on a method called from another method in the same bean. Typically, the entry point is a JAX-RS endpoint, followed by injection and call of a CDI bean that implements business logic. If that business logic is complex I have to split it up into multiple methods, some of them private.

In order to make this work, I need to move these methods to a different bean or use a self-inject hack. For example, as tested right now, Weld supports self-inject or Instance<> inject and that works fine for @ApplicationScoped and @RequestScoped beans but not @Dependent (circular dependency exception).

The current situation is bad for multiple reasons:

1. It forces developer to needlesly reorganise code into more beans than necessary.

2. It forces developer to remember to use a self inject which seems like a hack and anti-pattern.

3. You need to be aware of the internal workings of CDI proxies.

4. You get no compile time or linter warnings about the fact that interceptor will be ignored. You only notice the bug at runtime when testing and things work in some weird way.

5. For a beginner it is unintuitive why it doesn't "just work" by looking at the code. It just should.

@Timed(name = "timedMethod")
public void timedMethod() {
}

public void selfInvocationTimedMethod() {
    timedMethod();
}


Something like and opt-in "@AutoProxy" would keep backward compatibility while allowing us to instruct CDI runtime to automatically invoke all/specific bean methods as "business" methods.

Perhaps there is an even better solution but this is what seems to make the most sense from all the discussion I've read so far.


See also: https://issues.redhat.com/browse/CDI-414



Best regards, Cen

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