RowTag


1   package org.roller.presentation.tags;
2   
3   import org.apache.commons.logging.Log;
4   import org.apache.commons.logging.LogFactory;
5   import org.apache.struts.taglib.logic.IterateTag;
6   
7   import java.io.IOException  ;
8   
9   import javax.servlet.jsp.JspException  ;
10  import javax.servlet.jsp.JspWriter  ;
11  import javax.servlet.jsp.tagext.Tag  ;
12  
13  
14  /**
15   * <p>This tag generates table rows (i.e. &lt;tr&gt;....&lt;/tr&gt; elements) 
16   * with the background color set differently for alternating odd and even 
17   * rows. This tag only operates properly if embedded in an IterateTag.</p>
18   *
19   * <p>The following parameters can be specified for this Tag:</p>
20   * <ul>
21   * <li><code>oddColor </code> - The color for Odd numbered rows
22   * <li><code>evenColor</code> - The color for Even numbered rows
23   * <li><code>oddStyleClass</code> - The style class for Odd numbered rows
24   * <li><code>evenStyleClass</code> - The style class for Even numbered rows
25   * <li><code>align</code> - The alignment for the table row
26   * <li><code>valign</code> - The vertical alignment for the table row
27   * </ul>
28   *
29   * <p>Additionally this tag inherits the Event Handler and Style attributes
30   * from the BaseHandlerTag which can also be specified</p>
31   * 
32   * TODO Make RowTag work with STL's forEach tag too.
33   * 
34   * @jsp.tag name="row"
35   *
36   * @author Amarda Business Systems Ltd
37   * @version 1.0
38   */
39  public class RowTag extends org.apache.struts.taglib.html.BaseHandlerTag
40  {
41      // ----------------------------------------------------- Instance Variables
42      private static Log mLogger = LogFactory.getFactory()
43                                             .getInstance(RowTag.class);
44      protected final static String   QUOTE = "\"";
45  
46      /**
47       * Color of Odd rows in a table
48       */
49      protected String   oddColor = null;
50  
51      /**
52       *  Color of Even rows in a table
53       */
54      protected String   evenColor = null;
55  
56      /**
57       *  StyleClass of Odd rows in a table
58       */
59      protected String   oddStyleClass = null;
60  
61      /**
62       *  Style Class of Even rows in a table
63       */
64      protected String   evenStyleClass = null;
65  
66      /**
67       *  Alignment of the table row
68       */
69      protected String   align = null;
70  
71      /**
72       *  Vertical Alignment of the table row
73       */
74      protected String   valign = null;
75  
76      /**
77       * Return the color of Odd rows
78       * @jsp.attribute
79       */
80      public String   getOddColor()
81      {
82          return (this.oddColor);
83      }
84  
85      /**
86       * Set the color of Odd rows
87       *
88       * @param color HTML bgcolor value for Odd rows
89       */
90      public void setOddColor(String   color)
91      {
92          this.oddColor = color;
93      }
94  
95      /**
96       *  Return the color of Even rows
97       * @jsp.attribute
98       */
99      public String   getEvenColor()
100     {
101         return (this.evenColor);
102     }
103 
104     /**
105      * Set the color of Even rows
106      *
107      * @param color HTML bgcolor value for Even rows
108      */
109     public void setEvenColor(String   color)
110     {
111         this.evenColor = color;
112     }
113 
114     /**
115      * Return the Style Class of Odd rows
116      * @jsp.attribute
117      */
118     public String   getOddStyleClass()
119     {
120         return (this.oddStyleClass);
121     }
122 
123     /**
124      * Set the Style Class of Odd rows
125      *
126      * @param styleClass HTML Style Class value for Odd rows
127      */
128     public void setOddStyleClass(String   styleClass)
129     {
130         this.oddStyleClass = styleClass;
131     }
132 
133     /**
134      *  Return the Style Class of Even rows
135      * @jsp.attribute
136      */
137     public String   getEvenStyleClass()
138     {
139         return (this.evenStyleClass);
140     }
141 
142     /**
143      * Set the styleClass of Even rows
144      *
145      * @param styleClass HTML Style Class value for Even rows
146      */
147     public void setEvenStyleClass(String   styleClass)
148     {
149         this.evenStyleClass = styleClass;
150     }
151 
152     /**
153      *  Return the Alignment
154      * @jsp.attribute
155      */
156     public String   getAlign()
157     {
158         return (this.align);
159     }
160 
161     /**
162      * Set the Alignment
163      *
164      * @param Value for Alignment
165      */
166     public void setAlign(String   align)
167     {
168         this.align = align;
169     }
170 
171     /**
172      *  Return the Vertical Alignment
173      * @jsp.attribute
174      */
175     public String   getValign()
176     {
177         return (this.valign);
178     }
179 
180     /**
181      * Set the Vertical Alignment
182      *
183      * @param Value for Vertical Alignment
184      */
185     public void setValign(String   valign)
186     {
187         this.valign = valign;
188     }
189 
190     // ----------------------------------------------------- Public Methods
191 
192     /**
193      * Start of Tag processing
194      *
195      * @exception JspException if a JSP exception occurs
196      */
197     public int doStartTag() throws JspException  
198     {
199         // Continue processing this page
200         return EVAL_BODY_BUFFERED;
201     }
202 
203     /**
204      * End of Tag Processing
205      *
206      * @exception JspException if a JSP exception occurs
207      */
208     public int doEndTag() throws JspException  
209     {
210         StringBuffer   buffer = new StringBuffer  ();
211 
212 
213         // Create a <tr> element based on the parameters
214         buffer.append("<tr");
215 
216 
217         // Prepare this HTML elements attributes
218         prepareAttributes(buffer);
219 
220         buffer.append(">");
221 
222         // Add Body Content
223         if (bodyContent != null)
224         {
225             buffer.append(bodyContent.getString().trim());
226         }
227 
228         buffer.append("</tr>");
229 
230         // Render this element to our writer
231         JspWriter   writer = pageContext.getOut();
232 
233         try
234         {
235             writer.print(buffer.toString());
236         }
237         catch (IOException   e)
238         {
239             mLogger.error("ERROR in tag", e);
240             throw new JspException  ("Exception in RowTag doEndTag():" + 
241                                    e.toString());
242         }
243 
244         return EVAL_PAGE;
245     }
246 
247     /**
248      * Prepare the attributes of the HTML element
249      */
250     protected void prepareAttributes(StringBuffer   buffer)
251     {
252         // Determine if it is an "Odd" or "Even" row
253         boolean evenNumber = ((getRowNumber() % 2) == 0)                     
254                              ? true : false;
255 
256 
257         // Append bgcolor parameter
258         buffer.append(prepareBgcolor(evenNumber));
259 
260 
261         // Append CSS class parameter
262         buffer.append(prepareClass(evenNumber));
263 
264 
265         // Append "align" parameter
266         buffer.append(prepareAttribute("align", align));
267 
268 
269         // Append "valign" parameter
270         buffer.append(prepareAttribute("valign", valign));
271 
272 
273         // Append Event Handler details
274         buffer.append(prepareEventHandlers());
275 
276         try
277         {
278             // Append Style details
279             buffer.append(prepareStyles());
280         }
281         catch (Exception   e)
282         {
283             mLogger.error("Unexpected exception", e);
284         }
285     }
286 
287     /**
288      * Format attribute="value" from the specified attribute & value
289      */
290     protected String   prepareAttribute(String   attribute, String   value)
291     {
292         return (value == null)       
293                ? "" : " " + attribute + "=" + QUOTE + value + QUOTE;
294     }
295 
296     /**
297      * Format the bgcolor attribute depending on whether
298      * the row is odd or even.
299      *
300      * @param evenNumber Boolean set to true if an even numbered row
301      *
302      */
303     protected String   prepareBgcolor(boolean evenNumber)
304     {
305         if (evenNumber)
306         {
307             return prepareAttribute("bgcolor", evenColor);
308         }
309         else
310         {
311             return prepareAttribute("bgcolor", oddColor);
312         }
313     }
314 
315     /**
316      * Format the Style sheet class attribute depending on whether
317      * the row is odd or even.
318      *
319      * @param evenNumber Boolean set to true if an even numbered row
320      *
321      */
322     protected String   prepareClass(boolean evenNumber)
323     {
324         if (evenNumber)
325         {
326             return prepareAttribute("class", evenStyleClass);
327         }
328         else
329         {
330             return prepareAttribute("class", oddStyleClass);
331         }
332     }
333 
334     /**
335      * Determine the Row Number - from the IterateTag
336      */
337     protected int getRowNumber()
338     {
339         // Determine if embedded in an IterateTag
340         Tag tag = findAncestorWithClass(this, IterateTag.class);
341 
342         if (tag == null)
343         {
344             return 1;
345         }
346 
347         // Determine the current row number
348         IterateTag iterator = (IterateTag) tag;
349 
350         //        return iterator.getLengthCount() + 1;
351         return iterator.getIndex() + 1;
352     }
353 
354     /**
355      * Release resources after Tag processing has finished.
356      */
357     public void release()
358     {
359         super.release();
360 
361         oddColor = null;
362         evenColor = null;
363         oddStyleClass = null;
364         evenStyleClass = null;
365         align = null;
366         valign = null;
367     }
368 }
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags