LinkTag


1   /*
2    * $Id: LinkTag.java 164530 2005-04-25 03:11:07Z niallp $ 
3    *
4    * Copyright 1999-2005 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.net.MalformedURLException  ;
22  import java.util.HashMap  ;
23  import java.util.Map  ;
24  
25  import javax.servlet.jsp.JspException  ;
26  
27  import org.apache.struts.taglib.TagUtils;
28  import org.apache.struts.taglib.logic.IterateTag;
29  import org.apache.struts.util.MessageResources;
30  
31  /**
32   * Generate a URL-encoded hyperlink to the specified URI.
33   *
34   * @version $Rev: 164530 $ $Date: 2005-04-25 04:11:07 +0100 (Mon, 25 Apr 2005) $
35   */
36  public class LinkTag extends BaseHandlerTag {
37  
38  
39      // ----------------------------------------------------- Instance Variables
40  
41  
42      /**
43       * The body content of this tag (if any).
44       */
45      protected String   text = null;
46  
47      // ----------------------------------------------------- Constructor
48  
49      public LinkTag() {
50          super();
51          doDisabled = false;
52      }
53  
54  
55      // ------------------------------------------------------------- Properties
56  
57  
58      /**
59       * The anchor to be added to the end of the generated hyperlink.
60       */
61      protected String   anchor = null;
62  
63      public String   getAnchor() {
64          return (this.anchor);
65      }
66  
67      public void setAnchor(String   anchor) {
68          this.anchor = anchor;
69      }
70  
71  
72      /**
73       * <p>The logical forward name from which to retrieve the hyperlink URI.</p>
74       * <p>Usage note: If a forward config is used in a hyperlink,
75       * and a module is specified, the path must lead to another
76       * action and not directly to a page. This is in keeping with
77       * rule that in a modular application all links must be to
78       * an action rather than a page.
79       * </p>
80       */
81      protected String   forward = null;
82  
83      public String   getForward() {
84          return (this.forward);
85      }
86  
87      public void setForward(String   forward) {
88          this.forward = forward;
89      }
90  
91  
92      /**
93       * The hyperlink URI.
94       */
95      protected String   href = null;
96  
97      public String   getHref() {
98          return (this.href);
99      }
100 
101     public void setHref(String   href) {
102         this.href = href;
103     }
104 
105 
106     /**
107      * The link name for named links.
108      */
109     protected String   linkName = null;
110 
111     public String   getLinkName() {
112         return (this.linkName);
113     }
114 
115     public void setLinkName(String   linkName) {
116         this.linkName = linkName;
117     }
118 
119 
120     /**
121      * The message resources for this package.
122      */
123     protected static MessageResources messages =
124      MessageResources.getMessageResources(Constants.Package + ".LocalStrings");
125 
126 
127     /**
128      * The JSP bean name for query parameters.
129      */
130     protected String   name = null;
131 
132     public String   getName() {
133         return (this.name);
134     }
135 
136     public void setName(String   name) {
137         this.name = name;
138     }
139 
140 
141     /**
142      * The module-relative page URL (beginning with a slash) to which
143      * this hyperlink will be rendered.
144      */
145     protected String   page = null;
146 
147     public String   getPage() {
148         return (this.page);
149     }
150 
151     public void setPage(String   page) {
152         this.page = page;
153     }
154 
155 
156     /**
157      * The module-relative action (beginning with a slash) which will be
158      * called by this link
159      */
160     protected String   action = null;
161 
162     public String   getAction() {
163         return (this.action);
164     }
165 
166     public void setAction(String   action) {
167         this.action = action;
168     }
169 
170 
171     /**
172      * The module prefix (beginning with a slash) which will be
173      * used to find the action for this link.
174      */
175     protected String   module = null;
176 
177     public String   getModule() {
178         return (this.module);
179     }
180 
181     public void setModule(String   module) {
182         this.module = module;
183     }
184 
185 
186     /**
187       * The single-parameter request parameter name to generate.
188       */
189      protected String   paramId = null;
190 
191     public String   getParamId() {
192         return (this.paramId);
193     }
194 
195     public void setParamId(String   paramId) {
196         this.paramId = paramId;
197     }
198 
199 
200     /**
201      * The single-parameter JSP bean name.
202      */
203     protected String   paramName = null;
204 
205     public String   getParamName() {
206         return (this.paramName);
207     }
208 
209     public void setParamName(String   paramName) {
210         this.paramName = paramName;
211     }
212 
213 
214     /**
215      * The single-parameter JSP bean property.
216      */
217     protected String   paramProperty = null;
218 
219     public String   getParamProperty() {
220         return (this.paramProperty);
221     }
222 
223     public void setParamProperty(String   paramProperty) {
224         this.paramProperty = paramProperty;
225     }
226 
227 
228     /**
229      * The single-parameter JSP bean scope.
230      */
231     protected String   paramScope = null;
232 
233     public String   getParamScope() {
234         return (this.paramScope);
235     }
236 
237     public void setParamScope(String   paramScope) {
238         this.paramScope = paramScope;
239     }
240 
241 
242     /**
243      * The JSP bean property name for query parameters.
244      */
245     protected String   property = null;
246 
247     public String   getProperty() {
248         return (this.property);
249     }
250 
251     public void setProperty(String   property) {
252         this.property = property;
253     }
254 
255 
256     /**
257      * The scope of the bean specified by the name property, if any.
258      */
259     protected String   scope = null;
260 
261     public String   getScope() {
262         return (this.scope);
263     }
264 
265     public void setScope(String   scope) {
266         this.scope = scope;
267     }
268 
269 
270     /**
271      * The window target.
272      */
273     protected String   target = null;
274 
275     public String   getTarget() {
276         return (this.target);
277     }
278 
279     public void setTarget(String   target) {
280         this.target = target;
281     }
282 
283 
284     /**
285      * Include transaction token (if any) in the hyperlink?
286      */
287     protected boolean transaction = false;
288 
289     public boolean getTransaction() {
290         return (this.transaction);
291     }
292 
293     public void setTransaction(boolean transaction) {
294         this.transaction = transaction;
295     }
296 
297     /**
298      * Name of parameter to generate to hold index number
299      */
300     protected String   indexId = null;
301 
302     public String   getIndexId() {
303        return (this.indexId);
304     }
305 
306     public void setIndexId(String   indexId) {
307         this.indexId = indexId;
308     }
309 
310     protected boolean useLocalEncoding = false;
311     
312     public boolean isUseLocalEncoding() {
313        return useLocalEncoding;
314     }
315 
316     public void setUseLocalEncoding(boolean b) {
317        useLocalEncoding = b;
318     }
319 
320     // --------------------------------------------------------- Public Methods
321 
322 
323     /**
324      * Render the beginning of the hyperlink.
325      * <p>
326      * Support for indexed property since Struts 1.1
327      *
328      * @exception JspException if a JSP exception has occurred
329      */
330     public int doStartTag() throws JspException   {
331 
332         // Generate the opening anchor element
333         StringBuffer   results = new StringBuffer  ("<a");
334 
335         // Special case for name anchors
336         prepareAttribute(results, "name", getLinkName());
337 
338         // * @since Struts 1.1
339         if (getLinkName() == null || getForward() != null  || getHref() != null ||
340             getPage() != null || getAction() != null) {
341             prepareAttribute(results, "href", calculateURL());
342         }
343         prepareAttribute(results, "target", getTarget());
344         prepareAttribute(results, "accesskey", getAccesskey());
345         prepareAttribute(results, "tabindex", getTabindex());
346         results.append(prepareStyles());
347         results.append(prepareEventHandlers());
348         prepareOtherAttributes(results);
349         results.append(">");
350 
351         TagUtils.getInstance().write(pageContext, results.toString());
352 
353         // Evaluate the body of this tag
354         this.text = null;
355         return (EVAL_BODY_TAG);
356 
357     }
358 
359 
360 
361     /**
362      * Save the associated label from the body content.
363      *
364      * @exception JspException if a JSP exception has occurred
365      */
366     public int doAfterBody() throws JspException   {
367 
368         if (bodyContent != null) {
369             String   value = bodyContent.getString().trim();
370             if (value.length() > 0)
371                 text = value;
372         }
373         return (SKIP_BODY);
374 
375     }
376 
377 
378     /**
379      * Render the end of the hyperlink.
380      *
381      * @exception JspException if a JSP exception has occurred
382      */
383     public int doEndTag() throws JspException   {
384 
385         // Prepare the textual content and ending element of this hyperlink
386         StringBuffer   results = new StringBuffer  ();
387         if (text != null) {
388             results.append(text);
389         }
390         results.append("</a>");
391 
392         TagUtils.getInstance().write(pageContext, results.toString());
393 
394         return (EVAL_PAGE);
395 
396     }
397 
398 
399     /**
400      * Release any acquired resources.
401      */
402     public void release() {
403 
404         super.release();
405         anchor = null;
406         forward = null;
407         href = null;
408         linkName = null;
409         name = null;
410         page = null;
411         action = null;
412         module = null;
413         paramId = null;
414         paramName = null;
415         paramProperty = null;
416         paramScope = null;
417         property = null;
418         scope = null;
419         target = null;
420         text = null;
421         transaction = false;
422         indexId = null;
423         useLocalEncoding = false;
424 
425     }
426 
427 
428     // ------------------------------------------------------ Protected Methods
429 
430 
431     /**
432      * Return the complete URL to which this hyperlink will direct the user.
433      * Support for indexed property since Struts 1.1
434      *
435      * @exception JspException if an exception is thrown calculating the value
436      */
437     protected String   calculateURL() throws JspException   {
438 
439         // Identify the parameters we will add to the completed URL
440         Map   params = TagUtils.getInstance().computeParameters
441             (pageContext, paramId, paramName, paramProperty, paramScope,
442              name, property, scope, transaction);
443 
444         // if "indexed=true", add "index=x" parameter to query string
445         // * @since Struts 1.1
446         if( indexed ) {
447 
448            int indexValue = getIndexValue();
449 
450            //calculate index, and add as a parameter
451            if (params == null) {
452                params = new HashMap  ();             //create new HashMap if no other params
453            }
454            if (indexId != null) {
455               params.put(indexId, Integer.toString(indexValue));
456            } else {
457               params.put("index", Integer.toString(indexValue));
458            }
459         }
460 
461         String   url = null;
462         try {
463             url = TagUtils.getInstance().computeURLWithCharEncoding(pageContext, forward, href,
464                                           page, action, module, params, anchor, false, useLocalEncoding);
465         } catch (MalformedURLException   e) {
466             TagUtils.getInstance().saveException(pageContext, e);
467             throw new JspException  
468                 (messages.getMessage("rewrite.url", e.toString()));
469         }
470         return (url);
471 
472     }
473 
474 
475 }
476
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