ItemPartSupport


1   package com.blandware.atleap.webapp.taglib.core.menu.context;
2   
3   import javax.servlet.jsp.JspException  ;
4   import javax.servlet.jsp.JspTagException  ;
5   import javax.servlet.jsp.tagext.JspFragment  ;
6   import javax.servlet.jsp.tagext.SimpleTagSupport  ;
7   import java.io.IOException  ;
8   import java.io.StringWriter  ;
9   
10  /**
11   * <p>This class implements all common functionality of ItemPart. It renders
12   * its body if and only if <b>enabled</b> matches <code>enabled</code> attribute
13   * of parent <em>item</em> tag.
14   * </p>
15   * <p>
16   * Note: tag body may be rendered twice: first time for including in context
17   * menu, second time for including in page (of needed).
18   * </p>
19   * <p><a HREF="ItemPartSupport.java.htm"><i>View Source</i></a></p>
20   *
21   * @author Sergey Zubtcovskii <a HREF="mailto:sergey.zubtcovskii@blandware.com">&lt;sergey.zubtcovskii@blandware.com&gt;</a>
22   * @version $Revision: 1.3 $ $Date: 2005/09/21 13:46:05 $
23   */
24  public class ItemPartSupport extends SimpleTagSupport   implements ItemPart {
25  
26      /**
27       * Internal flag to decide, where to render body content
28       */
29      protected int renderingFlag = FLAG_RENDER_TO_PAGE;
30  
31      /**
32       * Internal flag initialized by tags which extend this one. Used to
33       * determine, whether or not to process body content
34       */
35      protected boolean enabled = false;
36  
37      /**
38       * Creates new instance of ItemPartSupport
39       */
40      public ItemPartSupport() {
41      }
42  
43      /**
44       * @see ItemPart#getRenderingFlag()
45       */
46      public int getRenderingFlag() {
47          return renderingFlag;
48      }
49  
50      /**
51       * Performs tag logic
52       *
53       * @throws javax.servlet.jsp.JspException
54       * @throws java.io.IOException
55       */
56      public void doTag() throws JspException  , IOException   {
57  
58          // search for parent item tag
59          ItemTag parentItemTag = (ItemTag) findAncestorWithClass(this, ItemTag.class);
60          if ( parentItemTag == null ) {
61              throw new JspTagException  ("This tag is only valid when nested within 'item' tag");
62          }
63  
64          if ( parentItemTag.getEnabled().booleanValue() == enabled ) {
65              JspFragment   body = getJspBody();
66              if ( body != null ) {
67                  if ( parentItemTag.getIncludeInContextMenu().booleanValue() ) {
68                      renderingFlag = FLAG_RENDER_TO_MENU;
69                      StringWriter   sw = new StringWriter  ();
70                      body.invoke(sw);
71                      parentItemTag.getItem().setContent(sw.toString().trim());
72                  }
73  
74                  if ( parentItemTag.getIncludeInPage().booleanValue() ) {
75                      renderingFlag = FLAG_RENDER_TO_PAGE;
76                      body.invoke(null);
77                  }
78              }
79          }
80      }
81  }
82
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