How to update process variable from event handler

Q&A
1

There is api to update process variable like: processApi.updateProcessDataInstance(“x”,processInstanceID, 100) but within isInterested(SEvent event) method of event handler i am not getting the reference of processApi. Within groovy script i can easily write like: apiAccessor.getProcessAPI().updateProcessDataInstance(“x”, processInstanceId, 100) but within event handler class i am not getting the reference of processApi.
Bonita BPM version is 6.3.2
java version “1.6.0_23”
tomcat & windows 7