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
18 package org.apache.commons.jexl2.internal;
19 import java.util.List;
20 import java.lang.reflect.Array;
21 /**
22 * Specialized executor to set a property in a List or array.
23 * @since 2.0
24 */
25 public final class ListSetExecutor extends AbstractExecutor.Set {
26 /** The java.lang.reflect.Array.get method used as an active marker in ListGet. */
27 private static final java.lang.reflect.Method ARRAY_SET =
28 initMarker(Array.class, "set", Object.class, Integer.TYPE, Object.class);
29 /** The java.util.obj.set method used as an active marker in ListSet. */
30 private static final java.lang.reflect.Method LIST_SET =
31 initMarker(List.class, "set", Integer.TYPE, Object.class);
32 /** The property. */
33 private final Integer property;
34
35 /**
36 * Creates an instance checking for the List interface or Array capability.
37 * @param is the introspector
38 * @param clazz the class that might implement the map interface
39 * @param key the key to use in obj.set(key,value)
40 * @param value the value to use in obj.set(key,value)
41 */
42 public ListSetExecutor(Introspector is, Class<?> clazz, Integer key, Object value) {
43 super(clazz, discover(clazz));
44 property = key;
45 }
46
47 /** {@inheritDoc} */
48 @Override
49 public Object getTargetProperty() {
50 return property;
51 }
52
53 /** {@inheritDoc} */
54 @Override
55 public Object execute(final Object obj, Object value) {
56 if (method == ARRAY_SET) {
57 java.lang.reflect.Array.set(obj, property.intValue(), value);
58 } else {
59 @SuppressWarnings("unchecked") // LSE should only be created for array or list types
60 final List<Object> list = (List<Object>) obj;
61 list.set(property.intValue(), value);
62 }
63 return value;
64 }
65
66 /** {@inheritDoc} */
67 @Override
68 public Object tryExecute(final Object obj, Object key, Object value) {
69 if (obj != null && method != null
70 && objectClass.equals(obj.getClass())
71 && key instanceof Integer) {
72 if (method == ARRAY_SET) {
73 Array.set(obj, ((Integer) key).intValue(), value);
74 } else {
75 @SuppressWarnings("unchecked") // LSE should only be created for array or list types
76 final List<Object> list = (List<Object>) obj;
77 list.set(((Integer) key).intValue(), value);
78 }
79 return value;
80 }
81 return TRY_FAILED;
82 }
83
84
85 /**
86 * Finds the method to perform 'set' on a obj of array.
87 * @param clazz the class to introspect
88 * @return a marker method, obj.set or array.set
89 */
90 static java.lang.reflect.Method discover(Class<?> clazz) {
91 if (clazz.isArray()) {
92 // we could verify if the call can be performed but it does not change
93 // the fact we would fail...
94 // Class<?> formal = clazz.getComponentType();
95 // Class<?> actual = value == null? Object.class : value.getClass();
96 // if (IntrospectionUtils.isMethodInvocationConvertible(formal, actual, false)) {
97 return ARRAY_SET;
98 // }
99 }
100 if (List.class.isAssignableFrom(clazz)) {
101 return LIST_SET;
102 }
103 return null;
104 }
105 }