The first thing you need to do is to update the following logger in the log4j.properties file of your distribution.
Change from this:
log4j.category.org.orbeon.oxf=WARN
# Uncomment to debug Orbeon forms
#log4j.category.org.orbeon.oxf.processor.DebugProcessor=INFO
to the following:
log4j.category.org.orbeon.oxf=WARN
# Uncomment to debug Orbeon forms
log4j.category.org.orbeon.oxf.processor.DebugProcessor=INFO
Then, you can put debug attribute to show defined values in xpl files of the form manager.
So, for example, in the act.xpl file, you could switch form:
<p:param name="data" type="input"/>
to
<p:param name="data" type="input" debug="act.xpl"/>
The orbeon logger will then show the content of data in the logs.
