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From d...@lexmark.com
Subject Indexed tags - proposal to add changes
Date Fri, 06 Jul 2001 17:31:21 GMT


Hi everyone.

I have been posting to the user list for some time now regarding creating
indexed names within an iterate tag.   From feedback from that list, this seems
to be an important addition to the current tags.

While looking to write my own additional tags which would do this (eg
html:indexedText etc), I discovered that this functionality could easily be
added to the current tags, now that the getIndex() method is available, by
creating an extra parameter 'indexed' which when set to true would create the
indexed names.  The necessary additions to current code were small and quite
clean, as follows:

- added 'indexed' as a parameter in BaseHandlerTag, with appropriate
setter/getter
- added if statement which checks for 'indexed=true', and if so, appends "[x]"
to the name, before appending property eg myProperty[x].value.
  This was added to BaseFieldTag (to cover tags which extend this) and
CheckBoxTag, & SelectTag
 as follows:
   //if "indexed=true" parameter, create indexed name for this tag eg
name="myCollection[x].myproperty"
   if ("true".equals(indexed))
   {
      // look for outer iterate tag
      IterateTag iterateTag = (IterateTag) findAncestorWithClass(this,
IterateTag.class);
      if (iterateTag == null)
      {
         // this tag should only be nested in iteratetag, if it's not, don't do
anything
         return EVAL_PAGE;
      }

      results.append(getName());
      results.append("[");
      results.append(iterateTag.getIndex());
      results.append("].");
   }

- Slight variations were added to SubmitTag and ButtonTag to simply add index to
it's name ie mySubmit[x].
- linkTag was somewhat different due to its nature.  I added if statement to add
"index=x" as a parameter to the link's querystring  ie myAction.do?index=1 or
myAction.do?param1=37&index=1, as follows:
        //if "indexed=true", add "index=x" parameter to query string
        if ("true".equals(indexed))
        {
           // look for outer iterate tag
           IterateTag iterateTag = (IterateTag) findAncestorWithClass(this,
IterateTag.class);
           if (iterateTag == null)
           {
               // this tag should only be nested in iteratetag, if it's not,
don't do anything
              System.out.println("couldn't find enclosing iterate tag");
              return EVAL_PAGE;
           }

           //calculate index, and add as a parameter
           if (params == null)
           {
               params = new HashMap();             //create new HashMap if no
other params
           }
           params.put("index", "" + iterateTag.getIndex());
        }
- minimal changes to struts-html.tld to add 'indexed' as param.

All of this code has been available at Ted's site for a while, and I would like
to suggest it is added to the Struts source.  Numerous people are already using
it, and I believe many more would if it was part of the build.

Would appreciate your feedback, and not sure what happens next (just joined this
list)!

Cheers,

Dave

PS  code attached(See attached file: struts indexed files.ZIP)




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