Hi Bo,
you set it in your jbpl definition, check out the testcases,
this is an example from Huisheng Xu's CacheParsingTest.java:
<process name='MyProcess' xmlns='http://jbpm.org/4.4/jpdl'>
<start name='start'>
<transition name='myTransition' to='end'>
<event-listener class='com.comp.MyEventListener' cache='disabled'/>
</transition>
</start>
<end name='end'/>
</process>