1 /*
2 * $Header: /home/cvs/jakarta-commons-sandbox/jelly/src/java/org/apache/commons/jelly/tags/define/DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $
3 * $Revision: 1.7 $
4 * $Date: 2002/05/17 15:18:12 $
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: DynamicTag.java,v 1.7 2002/05/17 15:18:12 jstrachan Exp $
61 */
62 package org.apache.commons.jelly.tags.betwixt;
63
64 import org.apache.commons.beanutils.Converter;
65 import org.apache.commons.beanutils.ConvertUtils;
66 import org.apache.commons.beanutils.ConversionException;
67
68 import org.apache.commons.betwixt.XMLIntrospector;
69 import org.apache.commons.betwixt.strategy.CapitalizeNameMapper;
70 import org.apache.commons.betwixt.strategy.DecapitalizeNameMapper;
71 import org.apache.commons.betwixt.strategy.HyphenatedNameMapper;
72 import org.apache.commons.betwixt.strategy.NameMapper;
73
74 import org.apache.commons.jelly.JellyException;
75 import org.apache.commons.jelly.MissingAttributeException;
76 import org.apache.commons.jelly.TagSupport;
77 import org.apache.commons.jelly.XMLOutput;
78
79 import org.apache.commons.logging.Log;
80 import org.apache.commons.logging.LogFactory;
81
82 /***
83 * Creates a Betwixt XMLIntrospector instance that can be used by the other Betwixt tags.</p>
84 *
85 * @author <a href="mailto:jstrachan@apache.org">James Strachan</a>
86 * @version $Revision: 1.7 $
87 */
88 public class IntrospectorTag extends TagSupport {
89
90 /*** The Log to which logging calls will be made. */
91 private static final Log log = LogFactory.getLog(IntrospectorTag.class);
92
93 private XMLIntrospector introspector;
94 private String var;
95
96 static {
97
98 // register converters to standard Strategies
99 ConvertUtils.register(
100 new Converter() {
101 public Object convert(Class type, Object value) {
102 if ( value instanceof String ) {
103 return createNameMapper((String) value);
104 }
105 else if ( value == null ) {
106 return null;
107 }
108 else {
109 throw new ConversionException(
110 "Don't know how to convert: " + value
111 + " of type: " + value.getClass().getName()
112 + " into a NameMapper"
113 );
114 }
115 }
116 },
117 NameMapper.class
118 );
119 }
120
121
122
123 public IntrospectorTag() {
124 }
125
126 // Tag interface
127 //-------------------------------------------------------------------------
128 public void doTag(final XMLOutput output) throws Exception {
129
130 if ( var == null ) {
131 throw new MissingAttributeException( "var" );
132 }
133 invokeBody(output);
134
135 XMLIntrospector introspector = getIntrospector();
136
137 context.setVariable( var, introspector );
138
139 // now lets clear this introspector so that its recreated again next time
140 this.introspector = null;
141 }
142
143 // Properties
144 //-------------------------------------------------------------------------
145
146 /***
147 * @return the current XMLIntrospector, lazily creating one if required
148 */
149 public XMLIntrospector getIntrospector() {
150 if ( introspector == null ) {
151 introspector = createIntrospector();
152 }
153 return introspector;
154 }
155
156 /***
157 * Sets whether attributes or elements should be used for primitive types.
158 * The default is false.
159 */
160 public void setAttributesForPrimitives(boolean attributesForPrimitives) {
161 getIntrospector().setAttributesForPrimitives(attributesForPrimitives);
162 }
163
164 /***
165 * Sets the name mapper used for element names.
166 * You can also use the Strings 'lowercase', 'uppercase' or 'hyphenated'
167 * as aliases to the common name mapping strategies or specify a class name String.
168 */
169 public void setElementNameMapper(NameMapper nameMapper) {
170 getIntrospector().setElementNameMapper(nameMapper);
171 }
172
173 /***
174 * Sets the name mapper used for attribute names.
175 * You can also use the Strings 'lowercase', 'uppercase' or 'hyphenated'
176 * as aliases to the common name mapping strategies or specify a class name String.
177 */
178 public void setAttributeNameMapper(NameMapper nameMapper) {
179 getIntrospector().setAttributeNameMapper(nameMapper);
180 }
181
182
183 /***
184 * Sets the variable name to output the new XMLIntrospector to.
185 * If this attribute is not specified then this tag must be nested
186 * inside an <parse> or <output> tag
187 */
188 public void setVar(String var) {
189 this.var = var;
190 }
191
192 // Implementation methods
193 //-------------------------------------------------------------------------
194
195 /***
196 * Static helper method which will convert the given string into
197 * standard named strategies such as 'lowercase', 'uppercase' or 'hyphenated'
198 * or use the name as a class name and create a new instance.
199 */
200 protected static NameMapper createNameMapper(String name) {
201 if ( name.equalsIgnoreCase( "lowercase" ) ) {
202 return new DecapitalizeNameMapper();
203 }
204 else if ( name.equalsIgnoreCase( "uppercase" ) ) {
205 return new CapitalizeNameMapper();
206 }
207 else if ( name.equalsIgnoreCase( "hyphenated" ) ) {
208 return new HyphenatedNameMapper();
209 }
210 else {
211 // lets try load the class of this name
212 Class theClass = null;
213 try {
214 theClass = Thread.currentThread().getContextClassLoader().loadClass( name );
215 }
216 catch (Exception e) {
217 throw new ConversionException( "Could not load class called: " + name, e );
218 }
219
220 Object object = null;
221 try {
222 object = theClass.newInstance();
223 }
224 catch (Exception e) {
225 throw new ConversionException( "Could not instantiate an instance of: " + name, e );
226 }
227 if ( object instanceof NameMapper ) {
228 return (NameMapper) object;
229 }
230 if ( object == null ) {
231 throw new ConversionException( "No NameMapper created for type: " + name );
232 }
233 else {
234 throw new ConversionException(
235 "Created object: " + object
236 + " is not a NameMapper! Its type is: " + object.getClass().getName()
237 );
238 }
239 }
240 }
241
242 /***
243 * Factory method to create a new XMLIntrospector
244 */
245 protected XMLIntrospector createIntrospector() {
246 return new XMLIntrospector();
247 }
248 }
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