Creating Custom annotations

Looking at the source codes of annotations provided by java 5 (like @Override, @SuppressWarnings etc), shows a simple enough code. However, I suppose there is an Annotation Processing Tool that ships in with the jdk 5 compiler that takes care of the functionality you need to implement with any annotation. But there must be some code that goes behind all these which the APT deciphers and brings out the functionality you want to implement. I am in seek of such codes and how to write them if I want to implement some custom functionality out of my custom annotations.

To be more precise, I am talking about the interpreter which will understand my annotation. Can I get some sample tutorial of such interpreter implementations ?

hi,

the short answer using Reflection:
just for Runtime-Processing you don't need the mentioned APT. You can just go with

Code:

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YourClassHere.class.getAnnotations()

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provided the given Annotation class uses Runtime-Retention

Code:

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@Retention(RetentionPolicy.RUNTIME)

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The longer answer not using Reflection:
In fact there is a pretty compact how-to for both Java 5 and 6 from Sun. java.sun.com/j2se/1.5.0/docs/guide/apt/GettingStarted.html (Sorry but forum-given I am a newbee) But the code is unneccessarryy un-understandable without deeper knowledge of the used (Sun) Mirror-API.

Anyways there is an promising project to simplify the APT-like Annotation compilation: apt-jelly.sourceforge.net (URL: sorry only 2 posts)

I hope that suffices for the first reply.