How to use

getAnnotation

method

in

com.google.gwt.core.ext.typeinfo.HasAnnotations

 @Override
 public synchronized ReflectionManifest get(Object key) {
  ReflectionManifest value = super.get(key);
  if (value == null) {
   value = new ReflectionManifest();
   @SuppressWarnings("unchecked") // private class
   K type = (K)key;
   value.cls = type.getAnnotation(KeepClass.class);
   value.method = type.getAnnotation(KeepMethod.class);
   value.field = type.getAnnotation(KeepField.class);
   value.constructor = type.getAnnotation(KeepConstructor.class);
   value.anno = type.getAnnotation(KeepAnnotation.class);
   put(type, value);
  }
  return value;
 }
}

public static <T extends Annotation> T getAnnotation(HasAnnotations classType, Class<T> annotationType) {
  try {
    T ann = classType.getAnnotation(annotationType);
    if (ann == null) {
      for (Annotation metaAnn : classType.getAnnotations()) {
        // only return a custom annotation if it contains the JacksonAnnotationsInside annotation
        if (metaAnn.annotationType().getAnnotation(JacksonAnnotationsInside.class) != null) {
          ann = metaAnn.annotationType().getAnnotation(annotationType);
          if (ann != null) {
            break;
          }
        }
      }
    }
    return ann;
  } catch (Exception ex) {
    return null;
  }
}

public static <T extends Annotation> T getAnnotation(HasAnnotations classType, Class<T> annotationType) {
  try {
    T ann = classType.getAnnotation(annotationType);
    if (ann == null) {
      for (Annotation metaAnn : classType.getAnnotations()) {
        // only return a custom annotation if it contains the JacksonAnnotationsInside annotation
        if (metaAnn.annotationType().getAnnotation(JacksonAnnotationsInside.class) != null) {
          ann = metaAnn.annotationType().getAnnotation(annotationType);
          if (ann != null) {
            break;
          }
        }
      }
    }
    return ann;
  } catch (Exception ex) {
    return null;
  }
}

/**
 * Returns the first occurence of the annotation found on the types
 *
 * @param annotation the annotation
 * @param hasAnnotationsList the types
 * @return the first occurence of the annotation found on the types
 * @param <T> a T object.
 */
public static <T extends Annotation> Optional<T> getAnnotation( Class<T> annotation, List<? extends HasAnnotations>
    hasAnnotationsList ) {
  for ( HasAnnotations accessor : hasAnnotationsList ) {
    if ( accessor.isAnnotationPresent( annotation ) ) {
      return Optional.of( accessor.getAnnotation( annotation ) );
    }
  }
  return Optional.absent();
}