Brief review of the Java annotations.

standard annotations
  • @Deprecated
  • @SuppressWarnings
  • @Override
meta-annotations
  • @Inherited
  • @Retention(RetentionPolicy.SOURCE / RetentionPolicy.CLASS / RetentionPolicy.RUNTIME)
  • @Target(ElementType.CONSTRUCTOR / ElementType.METHOD / ElementType.PACKAGE / ElementType. ) (Note that more than one ElementType is allowed here).
additional annotations

Here we go. Now we want to developp our own annotation. Example...

 @Documented  
 @Retention(SOURCE) 
 public @interface TODO { 
 
 	String value(); 
 	Level  level() default Level.NORMAL; 
 	public static enum Level { MINEUR, NORMAL, IMPORTANT }; 
 
 }

This will be used as follows :

 @TODO(value="whatever message we want here describing the TODO...", level=NORMAL)

Afterwards, we will have to tell the APT (annotation processing tool) what he is supposed to do with those annotations.
Source : http://developpez.com