再帰的にクラスのアノテーションを探索してアレする.java

import java.lang.annotation.Annotation;
import java.util.EnumSet;

import com.google.common.collect.Lists;

public class AnnotationRecursiveDigger {
	public interface Function<A extends Annotation> {
		void work(Class<?> cls, Class<?> superCls, A anno);
	}

	public enum Target {
		SuperClass, Interface,
	}

	public static <A extends Annotation> void processAnnotationDeep(Class<?> cls, Class<A> annotation, Class<?> targetCls, Function<A> function,
			EnumSet<Target> targets) {
		if (targets.contains(Target.SuperClass)) {
			Class<?> superCls = targetCls.getSuperclass();
			if (superCls != null) {
				processAnnotationDeep(cls, annotation, superCls, function, targets);
			}
		}
		if (targets.contains(Target.Interface)) {
			for (Class<?> superCls : targetCls.getInterfaces()) {
				processAnnotationDeep(cls, annotation, superCls, function, targets);
			}
		}
		A anno = targetCls.getAnnotation(annotation);

		if (anno != null) {
			function.work(cls, targetCls, anno);
		}
	}

	public static <A extends Annotation> void processAnnotationDeep(Class<?> cls, Class<A> annotation, Function<A> function, Target... targetArgs) {
		if (targetArgs == null || targetArgs.length == 0) {
			targetArgs = Target.values();
		}
		EnumSet<Target> targets = EnumSet.copyOf(Lists.newArrayList(targetArgs));

		processAnnotationDeep(cls, annotation, cls, function, targets);
	}

}