On Aug 6, 7:36 pm, Martin <[email protected]> wrote:
> Hi all there!
>
> I'm having problems to do the homework for annotations topic. Is that a new
> one? Because I can't find any help on this group..., and not much at other
> sites either...
>
> Well, the code I´m trying to run is this one:
>
> *import java.lang.annotation.*;
>
> public class MyOwnAnnotationExample {
>
> public MyOwnAnnotationExample() {
> }
>
> @RequestForEnhancement(id = 2868724,
> synopsis = "Enable time-travel",
> engineer = "Mr. Peabody",
> date = "4/1/3007")
> public String getSynopsis() {
> return synopsis;
> }
>
> public void printAnnotations() {
> Class c = this.getClass();
> Annotation[] annotations = c.getAnnotations();
> int numberOfAnnotations = annotations.length;
> System.out.println("Class " + c.getName() + " has " +
> numberOfAnnotations + " annotations");
>
> for (int i = 0 ; i < numberOfAnnotations; i++) {
> System.out.println("Annotation " + i + ": " + annotations[i] +
> ", type" + annotations[i].annotationType().getName());
> }
> }
>
> public static void main(String[] args) {
> MyOwnAnnotationExample moae = new MyOwnAnnotationExample();
> moae.printAnnotations();
> }
>
> }*
>
> And the output:
>
> *run:
> Class MyOwnAnnotationExample has 0 annotations
> BUILD SUCCESSFUL (total time: 1 second)*
>
> I guess the first problem is that in printAnnotations I´m trying to work
> with class while I'm annotating a method, but I don't get to know how to
> access the annotation of the getSynopsis() method.
>
> Can anyone give me any tips?
First, as you use a getSomething method which returns the value of a
variable, you should have a constructor with this variable to set it,
a private field for it, and call your class with a value for this
variable.
Next, after getting the class, you should get the declared methods on
this class (hint in my sentence you have almost the name of the method
to do it). This method returns an array of methods. Then you loop over
this array, and in the loop again you should get the declared
annotations for the method being inspected, which returns an array of
annotations. (you may here have your count number of annotations on
the method and print it using the method name). Again you loop over
the annotations, and use to method toString to print their fields.
Check also that you use @Target(ElementType.METHOD) annotation, and
@Retention(Retention.RUN TIME) annotation on the interface.
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