1 /*
2 * $Header: /home/cvs/jakarta-commons/betwixt/src/java/org/apache/commons/betwixt/expression/MethodUpdater.java,v 1.7 2003/01/12 13:52:03 rdonkin Exp $
3 * $Revision: 1.7 $
4 * $Date: 2003/01/12 13:52:03 $
5 *
6 * ====================================================================
7 *
8 * The Apache Software License, Version 1.1
9 *
10 * Copyright (c) 1999-2002 The Apache Software Foundation. All rights
11 * reserved.
12 *
13 * Redistribution and use in source and binary forms, with or without
14 * modification, are permitted provided that the following conditions
15 * are met:
16 *
17 * 1. Redistributions of source code must retain the above copyright
18 * notice, this list of conditions and the following disclaimer.
19 *
20 * 2. Redistributions in binary form must reproduce the above copyright
21 * notice, this list of conditions and the following disclaimer in
22 * the documentation and/or other materials provided with the
23 * distribution.
24 *
25 * 3. The end-user documentation included with the redistribution, if
26 * any, must include the following acknowlegement:
27 * "This product includes software developed by the
28 * Apache Software Foundation (http://www.apache.org/)."
29 * Alternately, this acknowlegement may appear in the software itself,
30 * if and wherever such third-party acknowlegements normally appear.
31 *
32 * 4. The names "The Jakarta Project", "Commons", and "Apache Software
33 * Foundation" must not be used to endorse or promote products derived
34 * from this software without prior written permission. For written
35 * permission, please contact apache@apache.org.
36 *
37 * 5. Products derived from this software may not be called "Apache"
38 * nor may "Apache" appear in their names without prior written
39 * permission of the Apache Group.
40 *
41 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
42 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
43 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
44 * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
45 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
46 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
47 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
48 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
49 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
50 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
51 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
52 * SUCH DAMAGE.
53 * ====================================================================
54 *
55 * This software consists of voluntary contributions made by many
56 * individuals on behalf of the Apache Software Foundation. For more
57 * information on the Apache Software Foundation, please see
58 * <http://www.apache.org/>.
59 *
60 * $Id: MethodUpdater.java,v 1.7 2003/01/12 13:52:03 rdonkin Exp $
61 */
62 package org.apache.commons.betwixt.expression;
63
64 import java.lang.reflect.Method;
65
66 import org.apache.commons.beanutils.ConvertUtils;
67 import org.apache.commons.logging.Log;
68 import org.apache.commons.logging.LogFactory;
69
70 /*** <p><code>MethodUpdater</code> updates the current bean context
71 * by calling a WriteMethod with the String value from the XML attribute
72 * or element.</p>
73 *
74 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
75 * @version $Revision: 1.7 $
76 */
77 public class MethodUpdater implements Updater {
78
79 /*** Logger */
80 private static Log log = LogFactory.getLog( MethodUpdater.class );
81
82 /***
83 * Programmatically set log
84 * @param aLog the implementation to which this class should log
85 */
86 public static void setLog( Log aLog ) {
87 log = aLog;
88 }
89
90 /*** The method to call on the bean */
91 private Method method;
92 /*** The type of the first parameter of the method */
93 private Class valueType;
94
95 /*** Base constructor */
96 public MethodUpdater() {
97 }
98
99 /***
100 * Convenience constructor sets method property
101 * @param method the Method to be invoked on the context's bean in the update
102 */
103 public MethodUpdater(Method method) {
104 setMethod( method );
105 }
106
107 /***
108 * Updates the current bean context with the given String value
109 * @param context the Context to be updated
110 * @param newValue the update to this new value
111 */
112 public void update(Context context, Object newValue) {
113 Object bean = context.getBean();
114 if ( bean != null ) {
115 if ( newValue instanceof String ) {
116 // try to convert into primitive types
117 newValue = ConvertUtils.convert( (String) newValue, valueType );
118 }
119 if ( newValue != null ) {
120 // check that it is of the correct type
121 /*
122 if ( ! valueType.isAssignableFrom( newValue.getClass() ) ) {
123 log.warn(
124 "Cannot call setter method: " + method.getName() + " on bean: " + bean
125 + " with type: " + bean.getClass().getName()
126 + " as parameter should be of type: " + valueType.getName()
127 + " but is: " + newValue.getClass().getName()
128 );
129 return;
130 }
131 */
132 }
133 Object[] arguments = { newValue };
134 try {
135 if ( log.isDebugEnabled() ) {
136 log.debug(
137 "Calling setter method: " + method.getName() + " on bean: " + bean
138 + " with new value: " + newValue
139 );
140 }
141 method.invoke( bean, arguments );
142
143 } catch (Exception e) {
144 String valueTypeName = (newValue != null) ? newValue.getClass().getName() : "null";
145 log.warn(
146 "Cannot evaluate method: " + method.getName() + " on bean: " + bean
147 + " of type: " + bean.getClass().getName() + " with value: " + newValue
148 + " of type: " + valueTypeName
149 );
150 handleException(context, e);
151 }
152 }
153 }
154
155 /***
156 * Gets the method which will be invoked by the update
157 *
158 * @return the Method to be invoked by the update
159 */
160 public Method getMethod() {
161 return method;
162 }
163
164 /***
165 * Sets the constant value of this expression
166 * @param method the Method to be invoked by the update
167 */
168 public void setMethod(Method method) {
169 this.method = method;
170 Class[] types = method.getParameterTypes();
171 if ( types == null || types.length <= 0 ) {
172 throw new IllegalArgumentException( "The Method must have at least one parameter" );
173 }
174 this.valueType = types[0];
175 }
176
177 // Implementation methods
178 //-------------------------------------------------------------------------
179
180 /***
181 * Strategy method to allow derivations to handle exceptions differently.
182 * @param context the Context being updated when this exception occured
183 * @param e the Exception that occured during the update
184 */
185 protected void handleException(Context context, Exception e) {
186 log.info( "Caught exception: " + e, e );
187 }
188
189 /***
190 * Returns something useful for logging.
191 * @return something useful for logging
192 */
193 public String toString() {
194 return "MethodUpdater [method=" + method + "]";
195 }
196 }
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