Java Reflection Annotation Find findAnnotationsMap(Class<T> a, Class<?> c)

Description

Same as #findAnnotations(Class,Class) except returns the annotations as a map with the keys being the class on which the annotation was found.

License

Apache License

Parameter

Parameter	Description
T	The annotation class type.
a	The annotation class type.
c	The class being searched.

Return

The found matches, or an empty map if annotation was not found.

Declaration

public static <T extends Annotation> LinkedHashMap<Class<?>, T> findAnnotationsMap(Class<T> a, Class<?> c)

Method Source Code

//package com.java2s;
// * Licensed to the Apache Software Foundation (ASF) under one or more contributor license agreements.  See the NOTICE file *

import java.lang.annotation.*;
import java.util.*;

public class Main {
    /**// w w w .j av  a 2  s .c  om
     * Same as {@link #findAnnotations(Class, Class)} except returns the annotations as a map
     * with the keys being the class on which the annotation was found.
     * <p>
     * Results are ordered child-to-parent.
     *
     * @param <T> The annotation class type.
     * @param a The annotation class type.
     * @param c The class being searched.
     * @return The found matches, or an empty map if annotation was not found.
     */
    public static <T extends Annotation> LinkedHashMap<Class<?>, T> findAnnotationsMap(Class<T> a, Class<?> c) {
        LinkedHashMap<Class<?>, T> m = new LinkedHashMap<Class<?>, T>();
        findAnnotationsMap(a, c, m);
        return m;
    }

    private static <T extends Annotation> void findAnnotationsMap(Class<T> a, Class<?> c, Map<Class<?>, T> m) {
        if (c == null)
            return;

        T t = getDeclaredAnnotation(a, c);
        if (t != null)
            m.put(c, t);

        findAnnotationsMap(a, c.getSuperclass(), m);

        for (Class<?> c2 : c.getInterfaces())
            findAnnotationsMap(a, c2, m);
    }

    /**
     * Returns the specified annotation only if it's been declared on the specified class.
     * <p>
     * More efficient than calling {@link Class#getAnnotation(Class)} since it doesn't
     *    recursively look for the class up the parent chain.
     *
     * @param <T> The annotation class type.
     * @param a The annotation class.
     * @param c The annotated class.
     * @return The annotation, or <jk>null</jk> if not found.
     */
    @SuppressWarnings("unchecked")
    public static <T extends Annotation> T getDeclaredAnnotation(Class<T> a, Class<?> c) {
        for (Annotation a2 : c.getDeclaredAnnotations())
            if (a2.annotationType() == a)
                return (T) a2;
        return null;
    }
}

Java Reflection Annotation Find findAnnotationsMap(Class a, Class c)