import org.apache.zookeeper.recipes.leader.LeaderElectionSupport.EventType; //导入依赖的package包/类
@Test
public void testReadyOffer() throws Exception {
    final ArrayList<EventType> events = new ArrayList<EventType>();
    final CountDownLatch electedComplete = new CountDownLatch(1);

    final LeaderElectionSupport electionSupport1 = createLeaderElectionSupport();
    electionSupport1.start();
    LeaderElectionSupport electionSupport2 = createLeaderElectionSupport();
    LeaderElectionAware listener = new LeaderElectionAware() {
        boolean stoppedElectedNode = false;
        @Override
        public void onElectionEvent(EventType eventType) {
            events.add(eventType);
            if (!stoppedElectedNode
                    && eventType == EventType.DETERMINE_COMPLETE) {
                stoppedElectedNode = true;
                try {
                    // stopping the ELECTED node, so re-election will happen.
                    electionSupport1.stop();
                } catch (Exception e) {
                    logger.error("Unexpected error", e);
                }
            }
            if (eventType == EventType.ELECTED_COMPLETE) {
                electedComplete.countDown();
            }
        }
    };
    electionSupport2.addListener(listener);
    electionSupport2.start();
    // waiting for re-election.
    electedComplete.await(CONNECTION_TIMEOUT / 3, TimeUnit.MILLISECONDS);

    final ArrayList<EventType> expectedevents = new ArrayList<EventType>();
    expectedevents.add(EventType.START);
    expectedevents.add(EventType.OFFER_START);
    expectedevents.add(EventType.OFFER_COMPLETE);
    expectedevents.add(EventType.DETERMINE_START);
    expectedevents.add(EventType.DETERMINE_COMPLETE);
    expectedevents.add(EventType.DETERMINE_START);
    expectedevents.add(EventType.DETERMINE_COMPLETE);
    expectedevents.add(EventType.ELECTED_START);
    expectedevents.add(EventType.ELECTED_COMPLETE);
    Assert.assertEquals("Events has failed to executed in the order",
            expectedevents, events);
    electionSupport2.stop();
}
 

import org.apache.zookeeper.recipes.leader.LeaderElectionSupport.EventType; //导入依赖的package包/类
/**
 * Called during each state transition. Current, low level events are provided
 * at the beginning and end of each state. For instance, START may be followed
 * by OFFER_START, OFFER_COMPLETE, DETERMINE_START, DETERMINE_COMPLETE, and so
 * on.
 * 
 * @param eventType
 */
public void onElectionEvent(EventType eventType);