CS639 Annotations Full Example

Foo.java: the class with annotations

public class Foo {

    @Test public static void m1() { }

    public static void m2() { }

    @Test public static void m3() {

        throw new RuntimeException("Boom");

    }

    public static void m4() { }

    @Test public static void m5() { }

    public static void m6() { }

    @Test public static void m7() {

        throw new RuntimeException("Crash");

    }

    public static void m8() { }

}

RunTests.java: the annotation processor

import java.lang.reflect.*;

public class RunTests {

   public static void main(String[] args) throws Exception {

      int passed = 0, failed = 0;

      for (Method m : Class.forName(args[0]).getMethods()) {

         if (m.isAnnotationPresent(Test.class)) {

            try {

               m.invoke(null);

               passed++;

            } catch (Throwable ex) {

               System.out.printf("Test %s failed: %s %n", m, ex.getCause());

               failed++;

            }

         }

      }

      System.out.printf("Passed: %d, Failed %d%n", passed, failed);

   }

}

Test.java: the annotation type declaration:

import java.lang.annotation.*;

/**

 * Indicates that the annotated method is a test method.

 * This annotation should be used only on parameterless static methods.

 */

@Retention(RetentionPolicy.RUNTIME)

@Target(ElementType.METHOD)

public @interface Test { }