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  1. import java.lang.annotation.*;
  2.  
  3. enum NoType {;}
  4.  
  5. @Retention(RetentionPolicy.RUNTIME)
  6. @Target(ElementType.METHOD)
  7. @interface A {
  8.     Class<?> data()  default NoType.class; // field from B
  9.     int      dataA() default 0;            // field from C
  10.     String   dataB() default "";           // field from C
  11. }
  12.  
  13. @Retention(RetentionPolicy.RUNTIME)
  14. @Target(ElementType.METHOD)
  15. @interface D {
  16.     A[] value() default {};
  17. }
  18.  
  19. class Foo {}
  20. class Bar {}
  21.  
  22. class Example {
  23.     @D({
  24.         @A(data = Bar.class),
  25.         @A(dataA = 5, dataB = "Bla"),
  26.         @A(data = Foo.class)
  27.     })
  28.     public static void main(String[] args) throws Exception {
  29.         for (A a : Example.class.getMethod("main", String[].class)
  30.                         .getAnnotation(D.class).value()) {
  31.             if (a.data() != NoType.class) {
  32.                 System.out.printf("B(%s)%n", a.data());
  33.             } else {
  34.                 System.out.printf("C(dataA = %d, dataB = \"%s\")%n",
  35.                     a.dataA(), a.dataB());
  36.             }
  37.         }
  38.     }
  39. }
Success #stdin #stdout 0.14s 29452KB
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Standard input is empty
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B(class Bar)
C(dataA = 5, dataB = "Bla")
B(class Foo)
https://ideone.com/EeV7BV
language:
Java (HotSpot 12)
created:
7 years ago
visibility:
public

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