1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/core/SetTag.java,v 1.7 2002/07/15 16:57:44 jstrachan Exp $
3 * $Revision: 1.7 $
4 * $Date: 2002/07/15 16:57:44 $
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: SetTag.java,v 1.7 2002/07/15 16:57:44 jstrachan Exp $
61 */
62 package org.apache.commons.jelly.tags.core;
63
64 import java.io.Writer;
65 import java.util.HashMap;
66 import java.util.Map;
67
68 import org.apache.commons.beanutils.BeanUtils;
69
70 import org.apache.commons.jelly.JellyContext;
71 import org.apache.commons.jelly.JellyException;
72 import org.apache.commons.jelly.Script;
73 import org.apache.commons.jelly.TagSupport;
74 import org.apache.commons.jelly.XMLOutput;
75 import org.apache.commons.jelly.expression.Expression;
76
77 import org.apache.commons.logging.Log;
78 import org.apache.commons.logging.LogFactory;
79
80
81 /*** A tag which sets a variable from the result of an expression
82 *
83 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
84 * @version $Revision: 1.7 $
85 */
86 public class SetTag extends TagSupport {
87
88 /*** The Log to which logging calls will be made. */
89 private static final Log log = LogFactory.getLog(SetTag.class);
90
91 /*** The variable name to export. */
92 private String var;
93
94 /*** The variable scope to export */
95 private String scope;
96
97 /*** The expression to evaluate. */
98 private Expression value;
99
100 /*** The target object on which to set a property. */
101 private Object target;
102
103 /*** The name of the property to set on the target object. */
104 private String property;
105
106 public SetTag() {
107 }
108
109 // Tag interface
110 //-------------------------------------------------------------------------
111 public void doTag(XMLOutput output) throws Exception {
112 Object answer = null;
113 if ( value != null ) {
114 answer = value.evaluate(context);
115 }
116 else {
117 answer = getBodyText();
118 }
119
120 if ( var != null ) {
121 if ( scope != null ) {
122 context.setVariable(var, scope, answer);
123 }
124 else {
125 context.setVariable(var, answer);
126 }
127 }
128 else {
129 if ( target == null ) {
130 throw new JellyException( "Either a 'var' or a 'target' attribute must be defined for this tag" );
131 }
132 if ( property == null ) {
133 throw new JellyException( "You must define a 'property' attribute if you specify a 'target'" );
134 }
135 setPropertyValue( target, property, answer );
136 }
137 }
138
139 // Properties
140 //-------------------------------------------------------------------------
141 /*** Sets the variable name to define for this expression
142 */
143 public void setVar(String var) {
144 this.var = var;
145 }
146
147 /***
148 * Sets the variable scope for this variable. For example setting this value to 'parent' will
149 * set this value in the parent scope. When Jelly is run from inside a Servlet environment
150 * then other scopes will be available such as 'request', 'session' or 'application'.
151 *
152 * Other applications may implement their own custom scopes.
153 */
154 public void setScope(String scope) {
155 this.scope = scope;
156 }
157
158 /*** Sets the expression to evaluate. */
159 public void setValue(Expression value) {
160 this.value = value;
161 }
162
163 /*** Sets the target object on which to set a property. */
164 public void setTarget(Object target) {
165 this.target = target;
166 }
167
168 /*** Sets the name of the property to set on the target object. */
169 public void setProperty(String property) {
170 this.property = property;
171 }
172
173 // Implementation methods
174 //-------------------------------------------------------------------------
175 protected void setPropertyValue( Object target, String property, Object value ) throws Exception {
176 try {
177 if ( target instanceof Map ) {
178 Map map = (Map) target;
179 map.put( property, value );
180 }
181 else {
182 BeanUtils.setProperty( target, property, value );
183 }
184 }
185 catch (Exception e) {
186 log.error( "Failed to set the property: " + property + " on bean: " + target + " to value: " + value + " due to exception: " + e, e );
187 }
188 }
189
190 }
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