Is there a way to mix or inherit the meaning of an annotation in Java?
I have an annotation like this
public @interface anno{
String a1() default "defaultValueA1";
String a2() default "defaultValueA2";
String a3() default "defaultValueA3"
}
Class SuperClass{
@anno(a1="myA1", a3="myA3")
private String field1;
}
Class SubClass extends SuperClass(){
@anno(a2="myA2", a3="defaultValueA3")
private String field1;
}
Currently when I try to get annotation from subclass anno only contains customized a2, but a1 can only get default, is there any way to get annotated mix for all superclasses specified as {a1:myA1, a2:myA2, a3:defaultValueA3}
but not {a1:defaultValueA1,a2:myA2, a3:defaultValueA3}
?
update:
I know the annotation is not inherited, so I tried to add subclass annotation {a1:defaultValueA1, a2:myA2, a3:defaultValueA3}
and superclass annotation {a1:myA1, a2: defalutValueA2, a3:myA3}
, my way is to get all subclass values of subClass and copy them to superClass annotation, but the problem is that I get all annotation value from subClass, I cannot determine which value is user defined and which value is derived from the default, who has a suggestion?
private void mixAnnotaiont(Annotation target, Annotation source){
Method[] methods = source.annotationType().getMethods();
Map<String, Object> sourceCfg = AnnotationUtils.getAnnotationAttributes(source);
for (int i = 0; i < methods.length; i++) {
// skip default value, but it incorrect, user may specify default value in subClass to overwrite superClass value
Object defaultValue = methods[i].getDefaultValue();
String name = methods[i].getName();
if(sourceCfg.get(name).equals(defaultValue)){
ignoreProperties.add(name);
}
}
BeanUtils.copyProperties(source, target, ignoreProperties.toArray(new String[] {}));
}
Thanks for your attention.
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Annotations are not inherited according to JavaDoc:
Open declaration annotation [] java.lang.Class.getDeclaredAnnotations ()
Returns all annotations that are directly present on this element. Unlike other methods in this interface, this method ignores inherited annotations. (Returns a zero-length array if no annotations are directly present on this element.) The caller of this method can modify the returned array; it will not affect the arrays returned by other callers.
But you can try to have a while loop and get all annotations declared using this method java.lang.Class.getSuperclass ()
while(loop thru the super class)
{
// get declared annotation
}
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