betweenGo

Photo taken by Stephen Laham.

Sometimes the resultant HTML from JSP files has too much white space.  This is because a lot of JSP logic will end up in only a few lines of actual HTML code and the rest is white space.

One efficient way to get rid of white space is to add this configuration to your web.xml on Tomcat/JBoss as described in this article, Trim Spaces in your JSP’s HTML.

    <init-param>
        <param-name>trimSpaces</param-name>
        <param-value>true</param-value>
    </init-param>

However this sometimes has undesired side-effects. For example this DSP:

<div class="foo">
  <dspel:valueof param="displayName" />
</div>

causes this undesired result:

<div class="foo"/>
  Frank Kim

The work around is to do this.

<dspel:getvalueof  var="displayName" param="displayName" />
<div  class="foo"><c:out  value="${displayName}"/></div>

The above problem might have been happening because we are running with a version of ATG that is for Servlet 2.3 but we are running with a version of JBoss that runs with Servlet 2.4.

There is another tip on removing white space in this JSP FAQ: Why I am getting extra whitespace in the output of my JSP?  In our code we had one file which included a bunch of tag libraries.  It originally looked like this.

<%/** Taglibs.jsp: include to pull in all taglibs */%>

<%@ taglib uri="/dspELTaglib" prefix="dspel" %>
<%@ taglib uri="/jstlCoreTaglib" prefix="c" %>
<%@ taglib uri="/struts-bean" prefix="bean" %>
<%@ taglib uri="/struts-tiles" prefix="tiles" %

When we changed it to this we saved about 5% in terms of page size in bytes.

<%@ taglib uri="/dspELTaglib" prefix="dspel"
%><%@ taglib uri="/jstlCoreTaglib" prefix="c"
%><%@ taglib uri="/struts-bean" prefix="bean"
%><%@ taglib uri="/struts-tiles" prefix="tiles" %>

You can use this tip with a DSP page and maintain indentation.

<dspel:page
  ><dspel:droplet name="/betweengo/droplet/Foo"
    ><dspel:oparam name="output"
      >Name: <dspel:valueof param="name"
    /></dspel:oparam
  ></dspel:droplet
></dspel:page>

In DSP to display formatted HTML text you use the valueishtml converter attribute.  For example:

<dspel:valueof param="displayName" valueishtml="true"/>

In JSTL to do this you tell JSTL not to escape the XML.  For example:

<c:out value="${displayName}" escapeXml="false" />

I create a JavaBean with a Set property because I wanted to enforce that there were only unique values in that Set.  However when I tried to use this JavaBean with a properties file, Nucleus complained it could not resolve the elements of the Set property.  When I changed the property to be a List or a String [] Nucleus had no problem.

Here is the properties file.

$class=com.betweengo.droplet.VerifyImages
$scope=request

# supported image dimensions
supportedImageDimensions=75x90,88x31,120x90

ATG Support pointed me to the Property Types subsection of the Using Nucleus
section of the ATG Programming Guide.  Specifically only these simple types are supported.  I am not sure why Set was excluded.

boolean
byte
char
short
int
long
float
double
java.lang.Boolean
java.lang.Byte
java.lang.Character
java.lang.Short
java.lang.Integer
java.lang.Long
java.lang.Float
java.lang.Double
java.lang.String
java.util.List
java.util.Map
java.util.Locale

Recently we noticed while running some ATG unit tests that tables were being created by the ATG repository if they had not already been created by our SQL scripts.  This was a functionality that I was unaware of but apparently it is not unique, Hibernate does this too.  I could not find any documentation about this nor could I determine how to turn it off.

The ATG repository creates these tables using the repository definition and the defaults for column width and data type.  It does not seem to warn that it is creating these tables.

When I use dspel:include within a custom tag like below things work fine.

<betweengo:link href="/click.do?id=foo"><dspel:include
page="/include/bar.jsp"/></betweengo:link>

However when I add flush=”true” it fails silently.

<betweengo:link href="/click.do?id=foo"><dspel:include
page="/include/bar.jsp" flush="true"/></betweengo:link>

The JSP page no longer renders after it gets to this line of code.  What puzzles me even more is that the documentation says that if you do not explicitly set flush, flush happens automatically.  Therefore theoretically adding flush=”true” should not have an effect though I do it because the documentation recommends doing it.

The above code is happening within a TargetingForEach droplet.  It is running on an ATG 2006.3 Patch 2 app server with JBoss 4.0.4.GA.

I contacted ATG support about this issue and they responded very quickly.  Basically they said don’t use flush=”true” on third party application servers and just rely on the automatic flush.

Entered on 07/29/2008 at 13:12:19 by Nicholas Glover:
Hi Frank,

You should note that JBoss 4.0.4 GA is not supported with any version of ATG and you should not be using it. Please stick with JBoss 4.0.3 SP1.

Also, it is imperative that you upgrade from your ATG version to the latest 2006.3 patch, patch 6. The latest patch has many bugfixes include a fix for one relating to flushing behavior, PR #134387.

Due to various bugs and issues encountered, use of the “flush” attribute with a 3rd party app server, is not really recommended. We are removing all docs for this feature in later versions of our documentation. In this case, flush=true is forcing an explicit flush on the current page; but if this is not set, a more “intelligent” auto flush is done that flushes top-level pages first and then progresses down the tree. This prevents problems with 3rd party app servers such as content getting rendered out of order. I recommend not messing with the “flush” setting.

Is there something you are trying to do that is not working that leads you to want to use the “flush” attribute?

Thanks.

–
Nick Glover
ATG Support

Entered on 07/29/2008 at 15:02:57 by Nicholas Glover:
Hi Frank,

I had already entered the documentation bug about this previously, but I polished and published it for our site with what I learned when looking into this for a prior customer and when looking into it for you.

It is PR #146637. Here’s the link:
http://www.atg.com/esupport/bugs/index.jsp?FullViewBug=ViewBug&bugId=146637

I’ll close this case now.

Thanks.

–
Nick Glover
ATG Support

Recently I was unable to create an item using the ACC because of an IllegalArgumentException.

java.lang.IllegalArgumentException:  Attempt to set
property named view (ContentList:800007)  with value =
moduleTemplate:2200004 (class=class atg.adapter.gsa.GSAItem).
This property  failed due to a property type specific test.
Enable loggingDebug for  details.

It turned out to be a simple issue of the wrong case. The repository path for the ContentList view item was:

/Betweengo/repository/Portal

when it should have been

/betweengo/repository/Portal.

This is certainly not obvious from the exception.

We were using the TargetingRange droplet to display a number of slides, starting with the 2nd slide.  We would never show more than 9 slides so we set howMany to 9.

What we found was that the TargetingRange droplet was always returning all the slides, including the first slide, no matter what we set for start.

Fortunately ATG support identified this problem as Bug #84551.  If the howMany param > number of targets returned then it ignores the start position parameter.

The work around is to make sure to set the howMany parameter to the number of items you expect.

It is relatively simple to dynamically create a dropdown from which you can jump to different parts of a page using JavaScript and ATG DSPEL.

First create the dropdown.

<form name="jumpTo" action=".">
  <dspel:droplet name="/atg/dynamo/droplet/ForEach">
    <dspel:param name="array" param="categories"/>
    <dspel:setvalue param="category" paramvalue="element"/>
    <dspel:oparam name="outputStart">
      <select name="names">
    </dspel:oparam>
    <dspel:oparam name="output">
      <dspel:getvalueof id="index" param="index"/>
      <c:set var="catShortName" value="cat${index}"/>
      <option value="<c:out value="${catShortName}"/>">
        <dspel:valueof param="category.name"/>
      </option>
    </dspel:oparam>
    <dspel:oparam name="outputEnd">
      </select>
    </dspel:oparam>
  </dspel:droplet>
</form>

Next create the button outside of the form for jumping to different parts of the page. I learned about the window.location.hash from this article. And I learned about how to access the selected value from the dropdown from this article.

 <input type="image" src="/img/buttons/update.gif"
   onClick="window.location.hash=
document.jumpTo.names.options[document.jumpTo.names.selectedIndex].value">

Finally you create the name anchors throughout your document.

<dspel:droplet name="/atg/dynamo/droplet/ForEach">
  <dspel:param name="array" param="categories"/>
  <dspel:setvalue param="category" paramvalue="element"/>
  <dspel:oparam name="output">

    <%-- magazine category --%>
    <dspel:getvalueof id="index" param="index"/>
    <c:set var="catShortName" value="cat${index}"/>
    <a name="<c:out value="${catShortName}"/>"
       id="<c:out value="${catShortName}"/>">
      <dspel:valueof param="category.name"/>
    </a>

  </dspel:oparam>
</dspel:droplet>

To log SQL turn on logging debug for your Repository component.

For example, set /betweengo/repository/Repository.loggingDebug to true.

Note that a lot of SQL statements are outputted. If you want to selectively turn it on and off you can put this in your JSP where you want to start logging SQL.

<dspel:setvalue bean="/betweengo/repository/Repository.loggingDebug"
                value="true"/>

And then put this in your JSP where you want to stop logging SQL.

<dspel:setvalue bean="/betweengo/repository/Repository.loggingDebug"
                value="false"/>

Note I think this solution only works if you are using a javax.sql.DataSource like in a JBoss configuration.