1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one
3 * or more contributor license agreements. See the NOTICE file
4 * distributed with this work for additional information
5 * regarding copyright ownership. The ASF licenses this file
6 * to you under the Apache License, Version 2.0 (the
7 * "License"); you may not use this file except in compliance
8 * with the License. You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.shiro.aop;
20
21 import java.lang.annotation.Annotation;
22 import java.lang.reflect.Method;
23
24 /**
25 * Default {@code AnnotationResolver} implementation that merely inspects the
26 * {@link MethodInvocation MethodInvocation}'s {@link MethodInvocation#getMethod() target method},
27 * and returns {@code targetMethod}.{@link Method#getAnnotation(Class) getAnnotation(class)}.
28 * <p/>
29 * Unfortunately Java's default reflection API for Annotations is not very robust, and this logic
30 * may not be enough - if the incoming method invocation represents a method from an interface,
31 * this default logic would not discover the annotation if it existed on the method implementation
32 * directly (as opposed to being defined directly in the interface definition).
33 * <p/>
34 * More complex class hierarchy traversal logic is required to exhaust a method's target object's
35 * classes, parent classes, interfaces and parent interfaces. That logic will likely be added
36 * to this implementation in due time, but for now, this implementation relies on the JDK's default
37 * {@link Method#getAnnotation(Class) Method.getAnnotation(class)} logic.
38 *
39 * @since 1.1
40 */
41 public class DefaultAnnotationResolver implements AnnotationResolver {
42
43 /**
44 * Returns {@code methodInvocation.}{@link org.apache.shiro.aop.MethodInvocation#getMethod() getMethod()}.{@link Method#getAnnotation(Class) getAnnotation(clazz)}.
45 *
46 * @param mi the intercepted method to be invoked.
47 * @param clazz the annotation class to use to find an annotation instance on the method.
48 * @return the discovered annotation or {@code null} if an annotation instance could not be
49 * found.
50 */
51 public Annotation getAnnotation(MethodInvocation mi, Class<? extends Annotation> clazz) {
52 if (mi == null) {
53 throw new IllegalArgumentException("method argument cannot be null");
54 }
55 Method m = mi.getMethod();
56 if (m == null) {
57 String msg = MethodInvocation.class.getName() + " parameter incorrectly constructed. getMethod() returned null";
58 throw new IllegalArgumentException(msg);
59
60 }
61 Annotation annotation = m.getAnnotation(clazz);
62 if (annotation == null ) {
63 Object miThis = mi.getThis();
64 //SHIRO-473 - miThis could be null for static methods, just return null
65 annotation = miThis != null ? miThis.getClass().getAnnotation(clazz) : null;
66 }
67 return annotation;
68 }
69 }