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1 | /* | |
2 | Chrysalis Web Framework [http://chrysalis.sourceforge.net] | |
3 | Copyright (c) 2002, 2003, 2004, Paul Strack | |
4 | ||
5 | All rights reserved. | |
6 | ||
7 | Redistribution and use in source and binary forms, with or without | |
8 | modification, are permitted provided that the following conditions are met: | |
9 | ||
10 | 1. Redistributions of source code must retain the above copyright notice, this | |
11 | list of conditions and the following disclaimer. | |
12 | ||
13 | 2. Redistributions in binary form must reproduce the above copyright notice, | |
14 | this list of conditions and the following disclaimer in the documentation | |
15 | and/or other materials provided with the distribution. | |
16 | ||
17 | 3. Neither the name of the copyright holder nor the names of its contributors | |
18 | may be used to endorse or promote products derived from this software without | |
19 | specific prior written permission. | |
20 | ||
21 | THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND | |
22 | ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED | |
23 | WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE | |
24 | DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR | |
25 | ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES | |
26 | (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | |
27 | LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON | |
28 | ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT | |
29 | (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS | |
30 | SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. | |
31 | */ | |
32 | ||
33 | package org.chwf.taglib.base; | |
34 | ||
35 | import javax.servlet.jsp.JspException; | |
36 | ||
37 | import org.apache.taglibs.standard.lang.support.ExpressionEvaluatorManager; | |
38 | import org.chwf.filter.BeanFilter; | |
39 | ||
40 | /** | |
41 | * A base tag for supporting manipulating object values. It is | |
42 | * intended for tags with var, object and/or property attributes. | |
43 | * | |
44 | * @author <a href="mailto:pfstrack@users.sourceforge.net">Paul Strack</a> | |
45 | */ | |
46 | 312 | public class ObjectTagSupport extends LifeCycleTagSupport { |
47 | ||
48 | /** A constant used to store the default object in the page context. */ | |
49 | 2 | public static final String DEFAULT_OBJECT = |
50 | ObjectTagSupport.class.getName() + ":DEFAULT_OBJECT"; | |
51 | ||
52 | /** Empty object array */ | |
53 | 1 | private static final Object[] EMPTY_ARRAY = new Object[0]; |
54 | ||
55 | /** Expression language attribute. */ | |
56 | private static final String EL_ATTRIBUTE = "el"; | |
57 | ||
58 | /** The variable name used to store retrieved properties. */ | |
59 | private String var; | |
60 | ||
61 | /** The object property. */ | |
62 | private String property; | |
63 | ||
64 | /** The object name (used for lookup). */ | |
65 | private String objectName; | |
66 | ||
67 | /** The object. */ | |
68 | private Object object; | |
69 | ||
70 | /** The object. */ | |
71 | private String el; | |
72 | ||
73 | /** | |
74 | * Clean up data for tag handler reuse and pooling. Should be overridden in | |
75 | * tag handler. Subclasses should always invoke their superclass's cleanup | |
76 | * method: <code>super.cleanup()</code> | |
77 | */ | |
78 | public void cleanup() { | |
79 | 20 | super.cleanup(); |
80 | 20 | this.var = null; |
81 | 20 | this.property = null; |
82 | 20 | this.objectName = null; |
83 | 20 | this.object = null; |
84 | 20 | this.el = null; |
85 | 20 | } |
86 | ||
87 | /** | |
88 | * The variable name used to store an object. Should be required if a tag | |
89 | * uses it. The tag should also invoke the <code>storeDefaultObject()<code> | |
90 | * method in its <code>doStart()</code> method. | |
91 | * | |
92 | * @param var The variable name. | |
93 | */ | |
94 | public void setVar(String var) { | |
95 | 6 | this.var = var; |
96 | 6 | } |
97 | ||
98 | /** | |
99 | * The variable name used to store an object. | |
100 | * | |
101 | * @return The variable name. | |
102 | */ | |
103 | public String getVar() { | |
104 | 6 | return this.var; |
105 | } | |
106 | ||
107 | /** | |
108 | * The object property being retrieved. Defaults to var if absent. | |
109 | * | |
110 | * @param property The property name. | |
111 | * @throws JspException If the property cannot be initialized. | |
112 | */ | |
113 | public void setProperty(String property) throws JspException { | |
114 | 95 | this.property = property; |
115 | 95 | } |
116 | ||
117 | /** | |
118 | * The object property being retrieved. Defaults to var if absent. | |
119 | * | |
120 | * @return The property name. | |
121 | */ | |
122 | public String getProperty() { | |
123 | 154 | if (this.property == null) { |
124 | 12 | return this.var; |
125 | } else { | |
126 | 142 | return this.property; |
127 | } | |
128 | } | |
129 | ||
130 | /** | |
131 | * The object name. Always optional. The tag will use the default object if | |
132 | * no object can is specified. | |
133 | * | |
134 | * @param objectName The object's name for lookup. | |
135 | * @throws JspException If the object cannot be found. | |
136 | */ | |
137 | public void setObject(String objectName) throws JspException { | |
138 | 147 | this.objectName = objectName; |
139 | 147 | this.object = pageContext.findAttribute(objectName); |
140 | 147 | if (this.object == null) { |
141 | 2 | throw new TagException( |
142 | TagException.MESSAGE_OBJECT_NOT_FOUND, | |
143 | new Object[] { objectName }); | |
144 | } | |
145 | 145 | } |
146 | ||
147 | /** | |
148 | * Get object name used to lookup the object. | |
149 | * | |
150 | * @return The object name. | |
151 | */ | |
152 | public String getObject() { | |
153 | 7 | return this.objectName; |
154 | } | |
155 | ||
156 | /** | |
157 | * Find the object for the tag or the default object if no object was | |
158 | * specified. | |
159 | * | |
160 | * @return The object. | |
161 | * @throws JspException If object not defined. | |
162 | */ | |
163 | public Object findObject() throws JspException { | |
164 | 105 | if (this.object == null) { |
165 | 37 | this.object = pageContext.findAttribute(DEFAULT_OBJECT); |
166 | 37 | if (this.object == null) { |
167 | 0 | throw new TagException(TagException.MESSAGE_OBJECT_NOT_DEFINED); |
168 | } | |
169 | } | |
170 | 105 | return this.object; |
171 | } | |
172 | ||
173 | /** | |
174 | * Store the default object. This method should be invoked in the tag | |
175 | * handler's <code>doStart()</code> method if the tag uses the var | |
176 | * attribute. | |
177 | * | |
178 | * @param object The new default object. | |
179 | */ | |
180 | public void storeDefaultObject(Object object) { | |
181 | 92 | if (object != null) { |
182 | 92 | pageContext.setAttribute(DEFAULT_OBJECT, object); |
183 | } | |
184 | 92 | } |
185 | ||
186 | /** | |
187 | * The JSTL Expression Language statement. | |
188 | * | |
189 | * @param el The JSTL Expression Language statement. | |
190 | */ | |
191 | public void setEl(String el) { | |
192 | 12 | this.el = el; |
193 | 12 | } |
194 | ||
195 | /** | |
196 | * The JSTL Expression Language statement. | |
197 | * | |
198 | * @return The JSTL Expression Language statement. | |
199 | */ | |
200 | public String getEl() { | |
201 | 39 | return this.el; |
202 | } | |
203 | ||
204 | /** | |
205 | * The tag result. The result is derived from one of the following, in | |
206 | * order of precedence: | |
207 | * | |
208 | * <ol> | |
209 | * <li>The result of the JSTL Expression Language statement.</li> | |
210 | * <li>The object property.</li> | |
211 | * <li>The object value.</li> | |
212 | * <li>The default object.</li> | |
213 | * </ol> | |
214 | * | |
215 | * @return The tag result. | |
216 | * @throws JspException For parsing failures. | |
217 | */ | |
218 | public Object getTagResult() throws JspException { | |
219 | 9 | return getTagResult(Object.class); |
220 | } | |
221 | ||
222 | /** | |
223 | * The tag result. As {@link #getTagResult()}, except that the result is | |
224 | * coerced to the expected class value. If the result cannot be coerced, | |
225 | * an error message is thrown. | |
226 | * | |
227 | * @param expectedClass The expected class value. | |
228 | * @return The tag result. | |
229 | * @throws JspException For parsing failures or if the result cannot be | |
230 | * correctly coerced. | |
231 | */ | |
232 | public Object getTagResult(Class expectedClass) throws JspException { | |
233 | 27 | if (getEl() != null) { |
234 | 6 | return getElResult(expectedClass); |
235 | 21 | } else if (findObject() != null) { |
236 | 21 | if (getProperty() == null) { |
237 | 4 | return getObjectResult(expectedClass); |
238 | } else { | |
239 | 17 | return getPropertyResult(expectedClass); |
240 | } | |
241 | } | |
242 | 0 | return null; |
243 | } | |
244 | ||
245 | /** | |
246 | * Get the result from an expression. | |
247 | * | |
248 | * @param expectedClass The expected class. | |
249 | * @return The tag result. | |
250 | * @throws JspException For parsing failures or if the result cannot be | |
251 | * correctly coerced. | |
252 | */ | |
253 | private Object getElResult(Class expectedClass) throws JspException { | |
254 | 6 | return ExpressionEvaluatorManager.evaluate( |
255 | EL_ATTRIBUTE, | |
256 | getEl(), | |
257 | expectedClass, | |
258 | this, | |
259 | this.pageContext); | |
260 | } | |
261 | ||
262 | /** | |
263 | * Get the result from the tag object. | |
264 | * | |
265 | * @param expectedClass The expected class. | |
266 | * @return The tag result. | |
267 | * @throws JspException If the result cannot be correctly coerced. | |
268 | */ | |
269 | private Object getObjectResult(Class expectedClass) throws JspException { | |
270 | 4 | Object value = findObject(); |
271 | 4 | if (!expectedClass.isInstance(value)) { |
272 | 0 | Object[] args = { getObject(), expectedClass.getName()}; |
273 | 0 | throw new TagException(TagException.MESSAGE_OBJECT_UNEXPECTED_TYPE, args); |
274 | } | |
275 | 4 | return value; |
276 | } | |
277 | ||
278 | /** | |
279 | * Get the result from the tag object property. | |
280 | * | |
281 | * @param expectedClass The expected class. | |
282 | * @return The tag result. | |
283 | * @throws JspException If the result cannot be correctly coerced. | |
284 | */ | |
285 | private Object getPropertyResult(Class expectedClass) throws JspException { | |
286 | 17 | Object value = BeanFilter.getProperty(findObject(), getProperty()); |
287 | 17 | if (!expectedClass.isInstance(value)) { |
288 | 0 | Object[] args = { getProperty(), getObject(), expectedClass.getName()}; |
289 | 0 | throw new TagException( |
290 | TagException.MESSAGE_PROPERTY_UNEXPECTED_TYPE, | |
291 | args); | |
292 | } | |
293 | 17 | return value; |
294 | } | |
295 | } |
this report was generated by version 1.0.5 of jcoverage. |
copyright © 2003, jcoverage ltd. all rights reserved. |