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 * https://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
21 import org.apache.commons.jexl3.JexlException;
22
23 /**
24 * Specialized executor to set a property of an object.
25 * <p>Duck as in duck-typing for an interface like:
26 * <code>
27 * interface Setable {
28 * Object set(Object property, Object value);
29 * }
30 * </code>
31 * or
32 * <code>
33 * interface Putable {
34 * Object put(Object property, Object value);
35 * }
36 * </code>
37 * </p>
38 * @since 2.0
39 */
40 public final class DuckSetExecutor extends AbstractExecutor.Set {
41 /**
42 * Discovers a DuckSetExecutor.
43 *
44 * @param is the introspector
45 * @param clazz the class to find the set method from
46 * @param key the key to use as 1st argument to the set method
47 * @param value the value to use as 2nd argument to the set method
48 * @return the executor if found, null otherwise
49 */
50 public static DuckSetExecutor discover(final Introspector is, final Class<?> clazz, final Object key, final Object value) {
51 java.lang.reflect.Method method = is.getMethod(clazz, "set", key, value);
52 if (method == null) {
53 method = is.getMethod(clazz, "put", makeArgs(key, value));
54 }
55 return method == null ? null : new DuckSetExecutor(clazz, method, key, value);
56 }
57 /** The property, may be null. */
58 private final Object property;
59
60 /** The property value class. */
61 private final Class<?> valueClass;
62
63 /**
64 * Creates an instance.
65 * @param clazz the class the set method applies to
66 * @param method the method called through this executor
67 * @param key the key to use as 1st argument to the set method
68 * @param value the value to use as 2nd argument to the set method
69 */
70 private DuckSetExecutor(final Class<?> clazz, final java.lang.reflect.Method method, final Object key, final Object value) {
71 super(clazz, method);
72 property = key;
73 valueClass = classOf(value);
74 }
75
76 @Override
77 public Object getTargetProperty() {
78 return property;
79 }
80
81 @Override
82 public Object invoke(final Object obj, final Object value) throws IllegalAccessException, InvocationTargetException {
83 final Object[] pargs = {property, value};
84 if (method != null) {
85 method.invoke(obj, pargs);
86 }
87 return value;
88 }
89
90 @Override
91 public Object tryInvoke(final Object obj, final Object key, final Object value) {
92 if (obj != null
93 && objectClass.equals(obj.getClass())
94 && method != null
95 && (property != null && property.equals(key)
96 || property == null && key == null)
97 && valueClass.equals(classOf(value))) {
98 try {
99 final Object[] args = {property, value};
100 method.invoke(obj, args);
101 return value;
102 } catch (IllegalAccessException | IllegalArgumentException xill) {
103 return TRY_FAILED; // fail
104 } catch (final InvocationTargetException xinvoke) {
105 throw JexlException.tryFailed(xinvoke); // throw
106 }
107 }
108 return TRY_FAILED;
109 }
110 }