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Java > Open Source Codes > com > tonbeller > wcf > scroller > ScrollerTag


1 package com.tonbeller.wcf.scroller;
2
3 import javax.servlet.jsp.JspException JavaDoc;
4 import javax.servlet.jsp.tagext.TagSupport JavaDoc;
5
6 import org.apache.log4j.Logger;
7
8 import com.tonbeller.wcf.controller.RequestContext;
9
10 /**
11  * Adds hidden fields to a form in a jsp that ensure that the browser keeps the
12  * scroll position when a user is navigating. This tag only works if
13  * the scroller.js javascript file is added to the page.
14  * <p>
15  * By default scrolling is disabled. A request handler should enable the
16  * scroller (@link com.tonbeller.wcf.scroller.Scroller) if its action
17  * requires keeping the scroll position
18  */

19 public class ScrollerTag extends TagSupport JavaDoc {
20
21   private static Logger logger = Logger.getLogger(ScrollerTag.class);
22   private Scroller scroller = new Scroller();
23
24   public int doStartTag() throws JspException JavaDoc {
25     return SKIP_BODY;
26   }
27
28   public int doEndTag() throws JspException JavaDoc {
29     try {
30       RequestContext context = RequestContext.instance();
31       scroller.handleRequest(context, pageContext.getOut());
32     } catch (Exception JavaDoc e) {
33       logger.error("", e);
34       throw new JspException JavaDoc(e);
35     }
36
37     return EVAL_PAGE;
38   }
39 }
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