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.jexl.util;
18
19 import java.lang.reflect.InvocationTargetException;
20
21 import org.apache.commons.jexl.util.introspection.Introspector;
22 import org.apache.commons.logging.Log;
23
24 /**
25 * Returned the value of object property when executed.
26 * @since 1.0
27 */
28 public class PropertyExecutor extends AbstractExecutor {
29
30 /** index of the first character of the property. */
31 private static final int PROPERTY_START_INDEX = 3;
32 /** The JEXL introspector used. */
33 protected Introspector introspector = null;
34
35 /** The method used. */
36 protected String methodUsed = null;
37
38 /**
39 * Constructor.
40 *
41 * @param r The log for this property executor instance.
42 * @param ispctr The JEXL introspector.
43 * @param clazz The class being examined.
44 * @param property The property being addressed.
45 */
46 public PropertyExecutor(Log r, Introspector ispctr,
47 Class clazz, String property) {
48 rlog = r;
49 introspector = ispctr;
50
51 discover(clazz, property);
52 }
53
54 /**
55 * Locate the getter method for this property.
56 *
57 * @param clazz The class being analyzed.
58 * @param property Name of the property.
59 */
60 protected void discover(Class clazz, String property) {
61 /*
62 * this is gross and linear, but it keeps it straightforward.
63 */
64
65 try {
66 char c;
67 StringBuffer sb;
68
69 Object[] params = {};
70
71 /*
72 * start with get<property>
73 * this leaves the property name
74 * as is...
75 */
76 sb = new StringBuffer("get");
77 sb.append(property);
78
79 methodUsed = sb.toString();
80
81 method = introspector.getMethod(clazz, methodUsed, params);
82
83 if (method != null) {
84 return;
85 }
86
87 /*
88 * now the convenience, flip the 1st character
89 */
90
91 c = sb.charAt(PROPERTY_START_INDEX);
92
93 if (Character.isLowerCase(c)) {
94 sb.setCharAt(PROPERTY_START_INDEX, Character.toUpperCase(c));
95 } else {
96 sb.setCharAt(PROPERTY_START_INDEX, Character.toLowerCase(c));
97 }
98
99 methodUsed = sb.toString();
100 method = introspector.getMethod(clazz, methodUsed, params);
101
102 if (method != null) {
103 return;
104 }
105 /**
106 * pass through application level runtime exceptions
107 */
108 } catch( RuntimeException e ) {
109 throw e;
110 } catch(Exception e) {
111 rlog.error("PROGRAMMER ERROR : PropertyExector() : " + e);
112 }
113 }
114
115
116 /**
117 * {@inheritDoc}
118 */
119 public Object execute(Object o)
120 throws IllegalAccessException, InvocationTargetException {
121 if (method == null) {
122 return null;
123 }
124
125 return method.invoke(o, null);
126 }
127 }
128