7

Client という抽象クラスがあります。子クラスの呼び出しメソッドで宣言された注釈にアクセスするにはどうすればよいですか? これを処理する最良の方法は何ですか?

public abstract class Client {

   protected void synchronize() {

      // How can I get the Annotation defined on inheriting class?   
      StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
      StackTraceElement lastStackElement =       stackTraceElements[stackTraceElements.length-1] ;
      Method m = this.getClass().getMethod(lastStackElement.getMethodName(),       String.class, int.class);
      m.getAnnotation(Cache.class);

      // synchronize data from server
   }

}

.

public class OrderClient extends Client {

   @Cache(minute = 5)
   public void synchronizrWithCustomerId(String customerId) {

      // So some stuff setup body and header

      super.synchronize();
   }

}
4

2 に答える 2

2

Based on your example this code works well:

public class TestS1 {

    public abstract class Client {

        protected void synchronize() throws NoSuchMethodException {
            // How can I get the Annotation defined on inheriting class?
            StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();
            StackTraceElement lastStackElement = stackTraceElements[2];

// take attention here: stackTraceElements[2]

     Method m = this.getClass().getMethod(lastStackElement.getMethodName(), String.class);
            Cache annotation = m.getAnnotation(Cache.class);
            System.out.println("Cache.minute = " + annotation.minute());
            // synchronize data from server
        }
    }

also you need to mark your annotation with @Retention(RetentionPolicy.RUNTIME)

    @Retention(RetentionPolicy.RUNTIME)
    @interface Cache {
        int minute();
    }

    public class OrderClient extends Client {
        @Cache(minute = 5)
        public void synchronizrWithCustomerId(String customerId) throws NoSuchMethodException {
            // So some stuff setup body and header
            super.synchronize();
        }
    }

    public void doTest() throws NoSuchMethodException {
        OrderClient oc = new OrderClient();
        oc.synchronizrWithCustomerId("blabla");
    }

    public static void main(String[] args) throws NoSuchMethodException {
        TestS1 t = new TestS1();
        t.doTest();
    }

}

Output is: Cache.minute = 5

于 2012-12-27T07:14:03.597 に答える
0

Andremoniyの答えは絶対に正しいです。私が変更したのは、スタックトレースでのルックアップ方法だけでした。

    Cache cache = null;

    try {
        StackTraceElement[] stackTraceElements = Thread.currentThread().getStackTrace();

        for (StackTraceElement element : stackTraceElements) {
            if (this.getClass().getName().equals(element.getClassName())) {
                Method method = this.getClass().getMethod(element.getMethodName(), String.class);
                cache = method.getAnnotation(Cache.class);
                break;
            }
        }
    } catch (NoSuchMethodException e) {
        e.printStackTrace();
    }
于 2012-12-27T07:35:40.933 に答える