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1 /*
2 * $Id: OptionsTag.java 190807 2005-06-15 21:01:56Z jholmes $
3 *
4 * Copyright 1999-2004 The Apache Software Foundation.
5 *
6 * Licensed under the Apache License, Version 2.0 (the "License");
7 * you may not use this file except in compliance with the License.
8 * You may obtain a copy of the License at
9 *
10 * http://www.apache.org/licenses/LICENSE-2.0
11 *
12 * Unless required by applicable law or agreed to in writing, software
13 * distributed under the License is distributed on an "AS IS" BASIS,
14 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15 * See the License for the specific language governing permissions and
16 * limitations under the License.
17 */
18
19 package org.apache.struts.taglib.html;
20
21 import java.lang.reflect.InvocationTargetException;
22 import java.util.Arrays;
23 import java.util.Collection;
24 import java.util.Enumeration;
25 import java.util.Iterator;
26 import java.util.Map;
27
28 import javax.servlet.jsp.JspException;
29 import javax.servlet.jsp.tagext.TagSupport;
30
31 import org.apache.commons.beanutils.PropertyUtils;
32 import org.apache.struts.util.IteratorAdapter;
33 import org.apache.struts.taglib.TagUtils;
34 import org.apache.struts.util.MessageResources;
35
36 /**
37 * Tag for creating multiple <select> options from a collection. The
38 * associated values displayed to the user may optionally be specified by a
39 * second collection, or will be the same as the values themselves. Each
40 * collection may be an array of objects, a Collection, an Enumeration,
41 * an Iterator, or a Map.
42 * <b>NOTE</b> - This tag requires a Java2 (JDK 1.2 or later) platform.
43 *
44 */
45
46 public class OptionsTag extends TagSupport {
47
48 /**
49 * The message resources for this package.
50 */
51 protected static MessageResources messages =
52 MessageResources.getMessageResources(Constants.Package + ".LocalStrings");
53
54 /**
55 * The name of the collection containing beans that have properties to
56 * provide both the values and the labels (identified by the
57 * <code>property</code> and <code>labelProperty</code> attributes).
58 */
59 protected String collection = null;
60
61 public String getCollection() {
62 return (this.collection);
63 }
64
65 public void setCollection(String collection) {
66 this.collection = collection;
67 }
68
69 /**
70 * Should the label values be filtered for HTML sensitive characters?
71 */
72 protected boolean filter = true;
73
74 public boolean getFilter() {
75 return filter;
76 }
77
78 public void setFilter(boolean filter) {
79 this.filter = filter;
80 }
81
82 /**
83 * The name of the bean containing the labels collection.
84 */
85 protected String labelName = null;
86
87 public String getLabelName() {
88 return labelName;
89 }
90
91 public void setLabelName(String labelName) {
92 this.labelName = labelName;
93 }
94
95 /**
96 * The bean property containing the labels collection.
97 */
98 protected String labelProperty = null;
99
100 public String getLabelProperty() {
101 return labelProperty;
102 }
103
104 public void setLabelProperty(String labelProperty) {
105 this.labelProperty = labelProperty;
106 }
107
108 /**
109 * The name of the bean containing the values collection.
110 */
111 protected String name = null;
112
113 public String getName() {
114 return name;
115 }
116
117 public void setName(String name) {
118 this.name = name;
119 }
120
121 /**
122 * The name of the property to use to build the values collection.
123 */
124 protected String property = null;
125
126 public String getProperty() {
127 return property;
128 }
129
130 public void setProperty(String property) {
131 this.property = property;
132 }
133
134 /**
135 * The style associated with this tag.
136 */
137 private String style = null;
138
139 public String getStyle() {
140 return style;
141 }
142
143 public void setStyle(String style) {
144 this.style = style;
145 }
146
147 /**
148 * The named style class associated with this tag.
149 */
150 private String styleClass = null;
151
152 public String getStyleClass() {
153 return styleClass;
154 }
155
156 public void setStyleClass(String styleClass) {
157 this.styleClass = styleClass;
158 }
159
160 /**
161 * Process the start of this tag.
162 *
163 * @exception JspException if a JSP exception has occurred
164 */
165
166 public int doStartTag() throws JspException {
167 return SKIP_BODY;
168 }
169
170 /**
171 * Process the end of this tag.
172 *
173 * @exception JspException if a JSP exception has occurred
174 */
175 public int doEndTag() throws JspException {
176
177 // Acquire the select tag we are associated with
178 SelectTag selectTag = (SelectTag) pageContext.getAttribute(Constants.SELECT_KEY);
179 if (selectTag == null) {
180 throw new JspException(messages.getMessage("optionsTag.select"));
181 }
182 StringBuffer sb = new StringBuffer();
183
184 // If a collection was specified, use that mode to render options
185 if (collection != null) {
186 Iterator collIterator = getIterator(collection, null);
187 while (collIterator.hasNext()) {
188
189 Object bean = collIterator.next();
190 Object value = null;
191 Object label = null;
192
193 try {
194 value = PropertyUtils.getProperty(bean, property);
195 if (value == null) {
196 value = "";
197 }
198 } catch (IllegalAccessException e) {
199 throw new JspException(
200 messages.getMessage("getter.access", property, collection));
201 } catch (InvocationTargetException e) {
202 Throwable t = e.getTargetException();
203 throw new JspException(
204 messages.getMessage("getter.result", property, t.toString()));
205 } catch (NoSuchMethodException e) {
206 throw new JspException(
207 messages.getMessage("getter.method", property, collection));
208 }
209
210 try {
211 if (labelProperty != null) {
212 label = PropertyUtils.getProperty(bean, labelProperty);
213 } else {
214 label = value;
215 }
216
217 if (label == null) {
218 label = "";
219 }
220 } catch (IllegalAccessException e) {
221 throw new JspException(
222 messages.getMessage("getter.access", labelProperty, collection));
223 } catch (InvocationTargetException e) {
224 Throwable t = e.getTargetException();
225 throw new JspException(
226 messages.getMessage("getter.result", labelProperty, t.toString()));
227 } catch (NoSuchMethodException e) {
228 throw new JspException(
229 messages.getMessage("getter.method", labelProperty, collection));
230 }
231
232 String stringValue = value.toString();
233 addOption(sb, stringValue, label.toString(), selectTag.isMatched(stringValue));
234
235 }
236
237 }
238
239 // Otherwise, use the separate iterators mode to render options
240 else {
241
242 // Construct iterators for the values and labels collections
243 Iterator valuesIterator = getIterator(name, property);
244 Iterator labelsIterator = null;
245 if ((labelName != null) || (labelProperty != null)) {
246 labelsIterator = getIterator(labelName, labelProperty);
247 }
248
249 // Render the options tags for each element of the values coll.
250 while (valuesIterator.hasNext()) {
251 Object valueObject = valuesIterator.next();
252 if (valueObject == null) {
253 valueObject = "";
254 }
255 String value = valueObject.toString();
256 String label = value;
257 if ((labelsIterator != null) && labelsIterator.hasNext()) {
258 Object labelObject = labelsIterator.next();
259 if (labelObject == null) {
260 labelObject = "";
261 }
262 label = labelObject.toString();
263 }
264 addOption(sb, value, label, selectTag.isMatched(value));
265 }
266 }
267
268 TagUtils.getInstance().write(pageContext, sb.toString());
269
270 return EVAL_PAGE;
271
272 }
273
274 /**
275 * Release any acquired resources.
276 */
277 public void release() {
278
279 super.release();
280 collection = null;
281 filter = true;
282 labelName = null;
283 labelProperty = null;
284 name = null;
285 property = null;
286 style = null;
287 styleClass = null;
288 }
289
290 // ------------------------------------------------------ Protected Methods
291
292 /**
293 * Add an option element to the specified StringBuffer based on the
294 * specified parameters.
295 *<p>
296 * Note that this tag specifically does not support the
297 * <code>styleId</code> tag attribute, which causes the HTML
298 * <code>id</code> attribute to be emitted. This is because the HTML
299 * specification states that all "id" attributes in a document have to be
300 * unique. This tag will likely generate more than one <code>option</code>
301 * element element, but it cannot use the same <code>id</code> value. It's
302 * conceivable some sort of mechanism to supply an array of <code>id</code>
303 * values could be devised, but that doesn't seem to be worth the trouble.
304 *
305 * @param sb StringBuffer accumulating our results
306 * @param value Value to be returned to the server for this option
307 * @param label Value to be shown to the user for this option
308 * @param matched Should this value be marked as selected?
309 */
310 protected void addOption(StringBuffer sb, String value, String label, boolean matched) {
311
312 sb.append("<option value=\"");
313 if (filter) {
314 sb.append(TagUtils.getInstance().filter(value));
315 } else {
316 sb.append(value);
317 }
318 sb.append("\"");
319 if (matched) {
320 sb.append(" selected=\"selected\"");
321 }
322 if (style != null) {
323 sb.append(" style=\"");
324 sb.append(style);
325 sb.append("\"");
326 }
327 if (styleClass != null) {
328 sb.append(" class=\"");
329 sb.append(styleClass);
330 sb.append("\"");
331 }
332
333 sb.append(">");
334
335 if (filter) {
336 sb.append(TagUtils.getInstance().filter(label));
337 } else {
338 sb.append(label);
339 }
340
341 sb.append("</option>\r\n");
342
343 }
344
345 /**
346 * Return an iterator for the option labels or values, based on our
347 * configured properties.
348 *
349 * @param name Name of the bean attribute (if any)
350 * @param property Name of the bean property (if any)
351 *
352 * @exception JspException if an error occurs
353 */
354 protected Iterator getIterator(String name, String property) throws JspException {
355
356 // Identify the bean containing our collection
357 String beanName = name;
358 if (beanName == null) {
359 beanName = Constants.BEAN_KEY;
360 }
361
362 Object bean = TagUtils.getInstance().lookup(pageContext, beanName, null);
363 if (bean == null) {
364 throw new JspException(messages.getMessage("getter.bean", beanName));
365 }
366
367 // Identify the collection itself
368 Object collection = bean;
369 if (property != null) {
370 try {
371 collection = PropertyUtils.getProperty(bean, property);
372 if (collection == null) {
373 throw new JspException(messages.getMessage("getter.property", property));
374 }
375 } catch (IllegalAccessException e) {
376 throw new JspException(messages.getMessage("getter.access", property, name));
377 } catch (InvocationTargetException e) {
378 Throwable t = e.getTargetException();
379 throw new JspException(
380 messages.getMessage("getter.result", property, t.toString()));
381 } catch (NoSuchMethodException e) {
382 throw new JspException(messages.getMessage("getter.method", property, name));
383 }
384 }
385
386 // Construct and return an appropriate iterator
387 if (collection.getClass().isArray()) {
388 collection = Arrays.asList((Object[]) collection);
389 }
390
391 if (collection instanceof Collection) {
392 return (((Collection) collection).iterator());
393
394 } else if (collection instanceof Iterator) {
395 return ((Iterator) collection);
396
397 } else if (collection instanceof Map) {
398 return (((Map) collection).entrySet().iterator());
399
400 } else if (collection instanceof Enumeration) {
401 return new IteratorAdapter((Enumeration) collection);
402
403 } else {
404 throw new JspException(
405 messages.getMessage("optionsTag.iterator", collection.toString()));
406 }
407 }
408
409 }