1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.jexl3.internal.introspection;
18
19 import java.lang.reflect.InvocationTargetException;
20 import org.apache.commons.jexl3.JexlException;
21
22 /**
23 * Specialized executor to set a property of an object.
24 * <p>Duck as in duck-typing for an interface like:
25 * <code>
26 * interface Setable {
27 * Object set(Object property, Object value);
28 * }
29 * </code>
30 * or
31 * <code>
32 * interface Putable {
33 * Object put(Object property, Object value);
34 * }
35 * </code>
36 * </p>
37 * @since 2.0
38 */
39 public final class DuckSetExecutor extends AbstractExecutor.Set {
40 /** The property, may be null. */
41 private final Object property;
42 /** The property value class. */
43 private final Class<?> valueClass;
44
45 /**
46 * Discovers a DuckSetExecutor.
47 *
48 * @param is the introspector
49 * @param clazz the class to find the set method from
50 * @param key the key to use as 1st argument to the set method
51 * @param value the value to use as 2nd argument to the set method
52 * @return the executor if found, null otherwise
53 */
54 public static DuckSetExecutor discover(final Introspector is, final Class<?> clazz, final Object key, final Object value) {
55 java.lang.reflect.Method method = is.getMethod(clazz, "set", key, value);
56 if (method == null) {
57 method = is.getMethod(clazz, "put", makeArgs(key, value));
58 }
59 return method == null? null : new DuckSetExecutor(clazz, method, key, value);
60 }
61
62 /**
63 * Creates an instance.
64 * @param clazz the class the set method applies to
65 * @param method the method called through this executor
66 * @param key the key to use as 1st argument to the set method
67 * @param value the value to use as 2nd argument to the set method
68 */
69 private DuckSetExecutor(final Class<?> clazz, final java.lang.reflect.Method method, final Object key, final Object value) {
70 super(clazz, method);
71 property = key;
72 valueClass = classOf(value);
73 }
74
75 @Override
76 public Object getTargetProperty() {
77 return property;
78 }
79
80 @Override
81 public Object invoke(final Object obj, final Object value) throws IllegalAccessException, InvocationTargetException {
82 final Object[] pargs = {property, value};
83 if (method != null) {
84 method.invoke(obj, pargs);
85 }
86 return value;
87 }
88
89 @Override
90 public Object tryInvoke(final Object obj, final Object key, final Object value) {
91 if (obj != null
92 && objectClass.equals(obj.getClass())
93 && method != null
94 && ((property != null && property.equals(key))
95 || (property == null && key == null))
96 && valueClass.equals(classOf(value))) {
97 try {
98 final Object[] args = {property, value};
99 method.invoke(obj, args);
100 return value;
101 } catch (IllegalAccessException | IllegalArgumentException xill) {
102 return TRY_FAILED;// fail
103 } catch (final InvocationTargetException xinvoke) {
104 throw JexlException.tryFailed(xinvoke); // throw
105 }
106 }
107 return TRY_FAILED;
108 }
109 }