Element


1   // ===========================================================================
2   // Copyright (c) 1996 Mort Bay Consulting Pty. Ltd. All rights reserved.
3   // $Id: Element.java,v 1.2 2004/04/30 01:16:55 laurent Exp $
4   // ---------------------------------------------------------------------------
5   
6   // Laurent Martelli <laurent@aopsys.com> - 21 mar. 2004:
7   // Added appendAttribute() and addCssClass() mehods
8   
9   package org.objectweb.jac.aspects.gui.web.html;
10  
11  import java.io.IOException  ;
12  import java.io.OutputStream  ;
13  import java.io.OutputStreamWriter  ;
14  import java.io.StringWriter  ;
15  import java.io.Writer  ;
16  import java.util.Enumeration  ;
17  import java.util.Hashtable  ;
18  import org.mortbay.util.Code;
19  
20  /* -------------------------------------------------------------------- */
21  /** HTML Element.
22   * <p>This abstract class is the base for all HTML Elements.
23   * The feature of an abstract HTML Element is that it can be added to
24   * HTML Pages, HTML Composites and several other HTML Elements derivations.
25   * Elements may also have attributes set, which are handled by the derived
26   * Element.
27   * @see org.mortbay.html.Page
28   * @see org.mortbay.html.Composite
29   * @version $Id: Element.java,v 1.2 2004/04/30 01:16:55 laurent Exp $
30   * @author Greg Wilkins
31  */
32  public abstract class Element
33  {
34      /* ----------------------------------------------------------------- */
35      public static final String  
36          noAttributes="",
37          ALIGN="align",
38          LEFT="left",
39          RIGHT="right",
40          CENTER="center",
41          VALIGN="valign",
42          TOP="top",
43          BOTTOM="bottom",
44          MIDDLE="middle",
45          WIDTH="width",
46          HEIGHT="height",
47          SIZE="size",
48          COLOR="color",
49          BGCOLOR="bgcolor",
50          STYLE="style",
51          CLASS="class",
52          ID="id";
53      
54          
55      
56      /* ----------------------------------------------------------------- */
57      /** Dimensions >=0 if set*/
58      private int width=-1;
59      private int height=-1;
60      private int size=-1;
61  
62      /* ----------------------------------------------------------------- */
63      /** The space separated string of HTML element attributes.
64       */
65      private String   attributes=null;
66      protected Hashtable   attributeMap=null;
67  
68      /* ----------------------------------------------------------------- */
69      /** Default constructor.
70       */
71      public Element(){}
72  
73      /* ----------------------------------------------------------------- */
74      /** Construct with attributes.
75       * @param attributes The initial attributes of the element
76       */
77      public Element(String   attributes)
78      {
79          attribute(attributes);
80      }
81  
82      /* ----------------------------------------------------------------- */
83      /** Write element to a Writer.
84       * This abstract method is called by the Page or other containing
85       * Element to write the HTML for this element. This must be implemented
86       * by the derived Element classes.
87       * @param out Writer to write the element to.
88       */
89      public abstract void write(Writer   out)
90           throws IOException  ;
91  
92      /* ----------------------------------------------------------------- */
93      /** Write Element to an OutputStream.
94       * Calls print(Writer) and checks errors
95       * Elements that override this method should also override
96       * write(Writer) to avoid infinite recursion.
97       * @param out OutputStream to write the element to.
98       */
99      public void write(OutputStream   out)
100          throws IOException  
101     {
102         Writer   writer = new OutputStreamWriter  (out);
103         write(writer);
104         writer.flush();
105     }
106     
107     /* ----------------------------------------------------------------- */
108     /** Write Element to an OutputStream.
109      * Calls print(Writer) and checks errors
110      * Elements that override this method should also override
111      * write(Writer) to avoid infinite recursion.
112      * @param out OutputStream to write the element to.
113      */
114     public void write(OutputStream   out, String   encoding)
115          throws IOException  
116     {
117         Writer   writer = new OutputStreamWriter  (out,encoding);
118         write(writer);
119         writer.flush();
120     }
121 
122     /* ----------------------------------------------------------------- */
123     public String   attributes()
124     {
125         if (attributes==null && attributeMap==null)
126             return noAttributes;
127 
128         StringBuffer   buf = new StringBuffer  (128);
129         synchronized(buf)
130         {
131             if (attributeMap!=null)
132             {
133                 Enumeration   e = attributeMap.keys();
134                 while (e.hasMoreElements())
135                 {
136                     buf.append(' ');
137                     String   a = (String  )e.nextElement();
138                     buf.append(a);
139                     buf.append('=');
140                     buf.append("\"");
141                     buf.append(attributeMap.get(a).toString());
142                     buf.append("\"");
143                 }
144             }
145             
146             if(attributes!=null && attributes.length()>0)
147             {
148                 if (!attributes.startsWith(" "))
149                     buf.append(' ');
150                 buf.append(attributes);
151             }
152         }
153 
154         return buf.toString();
155     }
156 
157     /* ----------------------------------------------------------------- */
158     /** Add element Attributes.
159      * The attributes are added to the Element attributes (separated with
160      * a space). The attributes are available to the derived class in the
161      * protected member String <I>attributes</I>
162      * @deprecated Use attribute(String).
163      * @param attributes String of HTML attributes to add to the element.
164      * @return This Element so calls can be chained.
165      */
166     public Element attributes(String   attributes)
167     {
168         if (Code.debug() && attributes!=null && attributes.indexOf('=')>=0)
169             Code.warning("Set attribute with old method: "+attributes+
170                          " on " + getClass().getName());
171 
172         if (attributes==null)
173         {
174             this.attributes=null;
175             return this;
176         }
177         
178         if (attributes==noAttributes)
179             return this;
180         
181         if (this.attributes==null)
182             this.attributes=attributes;
183         else
184             this.attributes += ' '+attributes;
185         return this;
186     }
187 
188     /* ------------------------------------------------------------ */
189     /** Set attributes from another Element.
190      * @param e Element
191      * @return This Element
192      */
193     public Element setAttributesFrom(Element e)
194     {
195         attributes=e.attributes;
196         attributeMap=(Hashtable  )e.attributeMap.clone();
197         return this;
198     }
199 
200     
201     /* ----------------------------------------------------------------- */
202     /** Add element Attributes.
203      * The attributes are added to the Element attributes (separated with
204      * a space). The attributes are available to the derived class in the
205      * protected member String <I>attributes</I>
206      * @param attributes String of HTML attributes to add to the element.
207      * A null attribute clears the current attributes.
208      * @return This Element so calls can be chained.
209      */
210     public Element attribute(String   attributes)
211     {
212         if (Code.debug() && attributes!=null && attributes.indexOf('=')>=0)
213             Code.warning("Set attribute with old method: "+attributes+
214                          " on " + getClass().getName());
215         
216         if (attributes==null ||
217             this.attributes==null ||
218             this.attributes==noAttributes ||
219             this.attributes.length()==0)
220             this.attributes=attributes;
221         else
222             this.attributes += ' '+attributes;
223         return this;
224     }
225     
226     /* ----------------------------------------------------------------- */
227     /** Add quoted element Attributes and value.
228      * @param attribute String of HTML attribute tag
229      * @param value String value of the attribute to be quoted
230      * @return This Element so calls can be chained.
231      */
232     public Element attribute(String   attribute, Object   value)
233     {
234         if (attributeMap==null)
235             attributeMap=new Hashtable  (10);
236         
237         if (value!=null)
238         {
239             if (value instanceof String   && ((String  )value).indexOf('"')!=-1)
240                 value=quoteAttributeValue((String  )value);
241 
242             attributeMap.put(attribute,value.toString());
243         }
244         return this;
245     }
246 
247     static String   quoteAttributeValue(String   value) {
248         String   s=(String  )value;
249         int q=0;
250         while((q=s.indexOf('"',q))>=0)
251         {
252             s=s.substring(0,q)+"&quot;"+s.substring(++q);
253             q+=6;
254         }
255         return s;
256     }
257 
258     public Element appendAttribute(String   attribute, Object   value) 
259     {
260         if (attributeMap==null)
261             attributeMap=new Hashtable  (10);
262         
263         if (value!=null)
264         {
265             if (value instanceof String   && ((String  )value).indexOf('"')!=-1)
266                 value=quoteAttributeValue((String  )value);
267             String   currentValue = (String  )attributeMap.get(attribute);
268             if (currentValue!=null)
269                 value = currentValue+value;
270             attributeMap.put(attribute,value);
271         }
272         return this;
273     }
274     /* ----------------------------------------------------------------- */
275     /** Add quoted element Attributes and value.
276      * @param attribute String of HTML attribute tag
277      * @param value String value of the attribute to be quoted
278      * @return This Element so calls can be chained.
279      */
280     public Element attribute(String   attribute, long value)
281     {
282         if (attributeMap==null)
283             attributeMap=new Hashtable  (10);
284         
285         attributeMap.put(attribute,Long.toString(value));
286         return this;
287     }
288 
289     /* ----------------------------------------------------------------- */
290     /** Convert Element to String.
291      * Uses write() to convert the HTML Element to a string.
292      * @return String of the HTML element
293      */
294     public String   toString()
295     {
296         try{
297             StringWriter   out = new StringWriter  ();
298             write(out);
299             out.flush();
300             return out.toString();
301         }
302         catch(IOException   e){
303             Code.ignore(e);
304         }
305         return null;    
306     }
307     
308     /* ----------------------------------------------------------------- */
309     /** left justify.
310      * Convenience method equivalent to attribute("align","left"). Not
311      * applicable to all Elements.
312      */
313     public Element left()
314     {
315         return attribute(ALIGN,LEFT);
316     }
317     
318     /* ----------------------------------------------------------------- */
319     /** right justify.
320      * Convenience method equivalent to attribute("align","right"). Not
321      * applicable to all Elements.
322      */
323     public Element right()
324     {
325         return attribute(ALIGN,RIGHT);
326     }
327     
328     /* ----------------------------------------------------------------- */
329     /** Center.
330      * Convenience method equivalent to attribute("align","center"). Not
331      * applicable to all Elements.
332      */
333     public Element center()
334     {
335         return attribute(ALIGN,CENTER);
336     }
337     
338     /* ----------------------------------------------------------------- */
339     /** Top align.
340      * Convenience method equivalent to attribute("valign","top"). Not
341      * applicable to all Elements.
342      */
343     public Element top()
344     {
345         return attribute(VALIGN,TOP);
346     }
347     
348     /* ----------------------------------------------------------------- */
349     /** Bottom align.
350      * Convenience method equivalent to attribute("valign","bottom"). Not
351      * applicable to all Elements.
352      */
353     public Element bottom()
354     {
355         return attribute(VALIGN,BOTTOM);
356     }
357     
358     /* ----------------------------------------------------------------- */
359     /** Middle align.
360      * Convenience method equivalent to attribute("valign","middle"). Not
361      * applicable to all Elements.
362      */
363     public Element middle()
364     {
365         return attribute(VALIGN,MIDDLE);
366     }
367     
368     /* ----------------------------------------------------------------- */
369     /** set width.
370      * Convenience method equivalent to attribute("width",w). Not
371      * applicable to all Elements.
372      */
373     public Element width(int w)
374     {
375         width=w;
376         return attribute(WIDTH,w);
377     }
378     
379     /* ----------------------------------------------------------------- */
380     /** set width.
381      * Convenience method equivalent to attribute("width",w). Not
382      * applicable to all Elements.
383      */
384     public Element width(String   w)
385     {
386         width=-1;
387         return attribute(WIDTH,w);
388     }
389     
390     /* ----------------------------------------------------------------- */
391     public int width()
392     {
393         return width;
394     }
395     
396     /* ----------------------------------------------------------------- */
397     /** set height.
398      * Convenience method equivalent to attribute("height",h). Not
399      * applicable to all Elements.
400      */
401     public Element height(int h)
402     {
403         height=h;
404         return attribute(HEIGHT,h);
405     }
406     
407     /* ----------------------------------------------------------------- */
408     /** set height.
409      * Convenience method equivalent to attribute("height",h). Not
410      * applicable to all Elements.
411      */
412     public Element height(String   h)
413     {
414         height=-1;
415         return attribute(HEIGHT,h);
416     }
417     
418     /* ----------------------------------------------------------------- */
419     public int height()
420     {
421         return height;
422     }
423     
424     /* ----------------------------------------------------------------- */
425     /** set size.
426      * Convenience method equivalent to attribute("size",s). Not
427      * applicable to all Elements.
428      */
429     public Element size(int s)
430     {
431         size=s;
432         return attribute(SIZE,s);
433     }
434     
435     /* ----------------------------------------------------------------- */
436     /** set size.
437      * Convenience method equivalent to attribute("size",s). Not
438      * applicable to all Elements.
439      */
440     public Element size(String   s)
441     {
442         size=-1;
443         return attribute(SIZE,s);
444     }
445     
446     /* ----------------------------------------------------------------- */
447     public int size()
448     {
449         return size;
450     }
451     
452     /* ----------------------------------------------------------------- */
453     /** set color.
454      * Convenience method equivalent to attribute("color",color). Not
455      * applicable to all Elements.
456      */
457     public Element color(String   color)
458     {
459         return attribute(COLOR,color);
460     }
461     
462     /* ----------------------------------------------------------------- */
463     /** set BGCOLOR.
464      * Convenience method equivalent to attribute("bgcolor",color). Not
465      * applicable to all Elements.
466      */
467     public Element bgColor(String   color)
468     {
469         return attribute(BGCOLOR,color);
470     }
471     
472     /* ----------------------------------------------------------------- */
473     /** set CSS CLASS.
474      */
475     public Element cssClass(String   c)
476     {
477         return attribute(CLASS,c);
478     }
479 
480     /* ----------------------------------------------------------------- */
481     /** add a css CLASS
482      */
483     public Element addCssClass(String   c)
484     {
485         return appendAttribute(CLASS," "+c);
486     }
487     
488     /* ----------------------------------------------------------------- */
489     /** set CSS ID.
490      * Convenience method equivalent to attribute("id",id).
491      */
492     public Element cssID(String   id)
493     {
494         return attribute(ID,id);
495     }
496     
497     /* ----------------------------------------------------------------- */
498     /** set Style.
499      * Convenience method equivalent to attribute("style",style).
500      */
501     public Element style(String   style)
502     {
503         return attribute(STYLE,style);
504     }
505 }
506 
507 
508 
509 
510
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