jBPM uses this utility method in Knowledge Helper

package org.drools.bpmn2

import org.kie.api.runtime.process.ProcessContext

rule "Auto-activate Hello1" ruleflow-group "Hello"
when
then
System.out.println(drools);
System.out.println(drools.getContext(ProcessContext.class)); System.out.println(drools.getContext(ProcessContext.class).getProcessInstance());
drools.getContext(ProcessContext.class).getProcessInstance().signalEvent("Hello1", null);
end