Complex display logic (was RE: speed of struts)

[Chris Birch <ch...@artlas.net>]

Hi,

I was hoping someone could point me to an elegant solution for the
following.

I have an ArrayList of objects which I use the Iterate tag view, lets say
there are 10 objects in it.  My requirement is to display the contents of
each object in a table cell and have three cells per row.  I cant work out
an elegant way of wrapping to the next row after every three iterates.  At
the moment, I get the iterate count and an if scriptlet to see if %3 == 0.
If so, I add a </tr><tr>.  Then when the iterate has finished, I need to
check the mod again with an if scriptlet and add extra <TD></TD> tags on the
end before the closing </tr>.  I have put the code snippet below.  The
annoying thing is the extra amount of work if I move to 4 columns...

Any help with doing this using struts tags would be appreciated as would
design pointers on coding my own tag or tag set.

Regards,
Chris.

    <%-- Scriptlet 0 - hold the idx value from iterate outside iterate
scope --%>
    <% int iterateIdx = 0; %>
    <logic:iterate id="foo" name="fooList" indexId="idx">
        <%-- Scriptlet 1 - List foo 3 abreast --%>
        <% iterateIdx = idx.intValue(); %>
        <% if (idx.intValue() % 3 == 0) { %>
        <tr>
            <td colspan="3"><hr></td>
        </tr>
        <tr>
        <% } // End if %>
        <%-- End Scriptlet 1 --%>
            <td width="33%">
                <table>
                    <tr>
                        <td>
                                <bean:write name="foo" property="bar"/>
                        </td>
                    </tr>
                    <tr>
                        <td>
                            <html:link  page="/anAction.do"
                                        paramId="fooId"
                                        paramName="foo"
                                        paramProperty="bar_id">
                                <app:img name="foo" property="barImgPath"/>
                            </html:link>
                        </td>
                    </tr>
                </table>
            </td>
        <%-- Scriptlet 2 - List artwork 3 abreast --%>
        <% if (idx.intValue() % 3 == 2) { %>
        </tr>
        <% } // End if %>
        <%-- End Scriptlet 2 --%>
    </logic:iterate>
    <%-- Scriptlet 3 - Tidy up --%>
    <% if (iterateIdx % 3 == 0) { %>
        <td>&nbsp;</td>
        <td>&nbsp;</td>
    </tr>
    <% } else if (iterateIdx % 3 == 1) { %>
        <td>&nbsp;</td>
    </tr>
    <% } %>
    <%-- End Scriptlet 3 --%>

-----Original Message-----
From: ltorrence@pfs.com [mailto:ltorrence@pfs.com]
Sent: 27 February 2002 14:17
To: struts-user@jakarta.apache.org
Subject: RE: speed of struts


I'm interested in hearing other opinion on this. I personally find the logic
present/equals tags to be ugly and cumbersome (not to mention inefficient in
terms of the generated servlet) and often find myself resorting to simple
if/else scriptlets instead. I'm not sure the logic tags win even from a
maintainabilit point of view.

How does everyone else deal with complex display logic? Do you use the logic
tags?

-----Original Message-----
From: Jim Downing [mailto:jimdowning@pobox.com]
Sent: Wednesday, February 27, 2002 8:17 AM
To: Struts Users Mailing List
Subject: Re: speed of struts


On Mon, Feb 11, 2002 at 03:01:12PM +0000, Ken.Horn@ubsw.com wrote:
> I'm curious as to the limit here. I'm currently building an app which
> has huge form requirements - I may have upwards of 500 fields as html
> text inputs -- very spreadsheet like. Where is the limitation?
> Rendering into html, or parsing the request into beans? I've had not
> problems so far with rendering speed, though I'm using Mozilla, so
> browser speed hasn't been noticable to far..

I've just finished a struts project where I had to move to scriptlets
away from struts tags for presentation logic. The problem was that
every now and then the GC would take a second or so to run. This
struck me as a VM issue (and may still have been, although it happened
under linux jdk1.2.2 and 1.3.1), but when I profiled the page I found
that the handful of tags I was using (10 - 20 logic equals, a few
logic:iterates) were generating 6M of garbage. Is this typical for all
taglibs? I dislike developing with scriptlets, but that's a pretty big
performance hit to have to take for a bit of maintainability.

Is this the same factor that limits pages to 50 form tags? What's the
best solution for pages with complex presentation logic?

jim
Jim Downing

jimdowning@pobox.com



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