Class.java 文件源码

/**
 * Returns all the annotations of this class. If there are no annotations
 * then an empty array is returned.
 *
 * @return a copy of the array containing this class' annotations.
 * @see #getDeclaredAnnotations()
 */
public Annotation[] getAnnotations() {
    /*
     * We need to get the annotations declared on this class, plus the
     * annotations from superclasses that have the "@Inherited" annotation
     * set.  We create a temporary map to use while we accumulate the
     * annotations and convert it to an array at the end.
     *
     * It's possible to have duplicates when annotations are inherited.
     * We use a Map to filter those out.
     *
     * HashMap might be overkill here.
     */
    HashMap<Class, Annotation> map = new HashMap<Class, Annotation>();
    Annotation[] annos = getDeclaredAnnotations();

    for (int i = annos.length-1; i >= 0; --i)
        map.put(annos[i].annotationType(), annos[i]);

    for (Class sup = getSuperclass(); sup != null;
            sup = sup.getSuperclass()) {
        annos = sup.getDeclaredAnnotations();
        for (int i = annos.length-1; i >= 0; --i) {
            Class clazz = annos[i].annotationType();
            if (!map.containsKey(clazz) &&
                    clazz.isAnnotationPresent(Inherited.class)) {
                map.put(clazz, annos[i]);
            }
        }
    }

    /* convert annotation values from HashMap to array */
    Collection<Annotation> coll = map.values();
    return coll.toArray(new Annotation[coll.size()]);
}