Decision : A decision decides between multiple paths of execution which are exclusive(独占的)
<process-definition name="the decision process">
<swimlane name="initiator"/>
<start-state name="start" swimlane="initiator">
<transition to="only descision">
</start-state>
<decision name="only descision">
<delegation class="org.jbpm.impl.DecisionTestDecisionHandler"/>
<transition name="left" to="inside the left street"/>
<transition name="right" to="inside the right street"/>
</decision>
<state name="inside the left street" swimlane="initiator">
<transition to="end"/>
</state>
<state name="inside the right street" swimlane="initiator">
<transition to="end"/>
</state>
<end-state name="end"/>
</process-definition>