Hi friend,

Custom Annotation





1)Annotations are metadata of a data.

2)Annotations to annotate a Java element.

3)An annotation show the declared element processed by a compiler,

4)development tool, deployment tool, or during runtime.

5)Annotations types are blueprints for annotations.



The code of a normal annotation type:



public @interface Anotaion {

int sValue();

String sOValue();

}



6).It can be processed statically before and during compile time.



7)It can be used before compile time mainly to generate supporting classes or configuration files





Categories of annotations



a)Marker annotations

e.g : @SingleAnnotationType



b)Single-value annotations

e.g : @SingleAnnotationType("datavalue")



c)Full annotations



@ShowElement(

{



@Element

(

severity=Element.CRITICAL,

item="item1", assignedTo="AT1"

),

@Element

(

severity=Element.IMPOTANT,

item="Item2", assignedTo="AT1" )



)

}

Marker: Marker type annotations have no elements



1)Example



public @interface SingleAnnotation {

}



@SingleAnnotation

public void mymethod() {

....

}



Single-Element:Annotations provide a data only.



public @interface SingleElement

{

String doWork();

}



Usage:



@SingleElement("Do work")

public void SingleMethodType() {

....

}





Full-value type annotations have multiple data members.



public @interface MultipleAnnotation {

String doWork();

int ecounter; String date();

}





@MyAnnotation (doSomething="Do work", ecount=5,

date="2008-08-08")

public void MultipleMethod() {

....

}




--------------------------------------------

Thanks & Regards

vineet