Passing an empty string as parameter

[John Armstrong]

Hi, everybody.

I'm trying to use a single workflow to kick off my Java Tools.  A few of 
the tools take some JVM options to run properly, but most don't.  I'm 
using a Java action like this:

<java>
  <job-tracker>${jobTracker}</job-tracker>
  <name-node>${nameNode}</name-node>
  <job-xml>${spinozaConfigFile}</job-xml>
  <main-class>${toolClass}</main-class>
  <java-opts>${jvmOptions}</java-opts>
  <arg>${commandLineProperties}</arg>
</java>

My problem is that I can't figure out what to do when I don't need to 
add any JVM options.  I'd hoped that passing an empty string -- 
jvmOptions == "" -- would do the trick, but it seems that when I pass 
this in through OozieClient it gets trimmed to "no value", and then the 
workflow complains that it can't resolve the EL expression.  I tried 
making it be a single space -- jvmOptions == " " -- but that gets 
trimmed as well.

So, are there any ideas?  Is it possible to include the java-opts tag if 
and only if ${jvmOptions} can be resolved?

Thanks.