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.jexl3.internal.introspection;
19
20 import java.lang.reflect.Field;
21 import java.lang.reflect.Modifier;
22 import org.apache.commons.jexl3.introspection.JexlPropertySet;
23
24 /**
25 * A JexlPropertySet for public fields.
26 */
27 public final class FieldSetExecutor implements JexlPropertySet {
28 /**
29 * The public field.
30 */
31 private final Field field;
32
33 /**
34 * Attempts to discover a FieldSetExecutor.
35 *
36 * @param is the introspector
37 * @param clazz the class to find the get method from
38 * @param identifier the key to use as an argument to the get method
39 * @param value the value to set the field to
40 * @return the executor if found, null otherwise
41 */
42 public static JexlPropertySet discover(final Introspector is,
43 final Class<?> clazz,
44 final String identifier,
45 final Object value) {
46 if (identifier != null) {
47 final Field field = is.getField(clazz, identifier);
48 if (field != null
49 && !Modifier.isFinal(field.getModifiers())
50 && (value == null || MethodKey.isInvocationConvertible(field.getType(), value.getClass(), false))) {
51 return new FieldSetExecutor(field);
52 }
53 }
54 return null;
55 }
56
57 /**
58 * Creates a new instance of FieldPropertySet.
59 * @param theField the class public field
60 */
61 private FieldSetExecutor(final Field theField) {
62 field = theField;
63 }
64
65 @Override
66 public Object invoke(final Object obj, final Object arg) throws Exception {
67 field.set(obj, arg);
68 return arg;
69 }
70
71 @Override
72 public Object tryInvoke(final Object obj, final Object key, final Object value) {
73 if (obj.getClass().equals(field.getDeclaringClass())
74 && key.equals(field.getName())
75 && (value == null || MethodKey.isInvocationConvertible(field.getType(), value.getClass(), false))) {
76 try {
77 field.set(obj, value);
78 return value;
79 } catch (final IllegalAccessException xill) {
80 return Uberspect.TRY_FAILED;
81 }
82 }
83 return Uberspect.TRY_FAILED;
84 }
85
86 @Override
87 public boolean tryFailed(final Object rval) {
88 return rval == Uberspect.TRY_FAILED;
89 }
90
91 @Override
92 public boolean isCacheable() {
93 return true;
94 }
95 }