Examples with UUID java.util.UUID used on opensource projects

Example 46 with UUID

use of java.util.UUID in project flink by apache.

the class ZooKeeperLeaderElectionService method nodeChanged.

@Override
public void nodeChanged() throws Exception {
    try {
        // leaderSessionID is null if the leader contender has not yet confirmed the session ID
        if (leaderLatch.hasLeadership()) {
            synchronized (lock) {
                if (LOG.isDebugEnabled()) {
                    LOG.debug("Leader node changed while {} is the leader with session ID {}.", leaderContender.getAddress(), confirmedLeaderSessionID);
                }
                if (confirmedLeaderSessionID != null) {
                    ChildData childData = cache.getCurrentData();
                    if (childData == null) {
                        if (LOG.isDebugEnabled()) {
                            LOG.debug("Writing leader information into empty node by {}.", leaderContender.getAddress());
                        }
                        writeLeaderInformation(confirmedLeaderSessionID);
                    } else {
                        byte[] data = childData.getData();
                        if (data == null || data.length == 0) {
                            // the data field seems to be empty, rewrite information
                            if (LOG.isDebugEnabled()) {
                                LOG.debug("Writing leader information into node with empty data field by {}.", leaderContender.getAddress());
                            }
                            writeLeaderInformation(confirmedLeaderSessionID);
                        } else {
                            ByteArrayInputStream bais = new ByteArrayInputStream(data);
                            ObjectInputStream ois = new ObjectInputStream(bais);
                            String leaderAddress = ois.readUTF();
                            UUID leaderSessionID = (UUID) ois.readObject();
                            if (!leaderAddress.equals(this.leaderContender.getAddress()) || (leaderSessionID == null || !leaderSessionID.equals(confirmedLeaderSessionID))) {
                                // the data field does not correspond to the expected leader information
                                if (LOG.isDebugEnabled()) {
                                    LOG.debug("Correcting leader information by {}.", leaderContender.getAddress());
                                }
                                writeLeaderInformation(confirmedLeaderSessionID);
                            }
                        }
                    }
                }
            }
        }
    } catch (Exception e) {
        leaderContender.handleError(new Exception("Could not handle node changed event.", e));
        throw e;
    }
}

Example 47 with UUID

use of java.util.UUID in project flink by apache.

the class SingleLeaderElectionServiceTest method testShutdown.

@Test
public void testShutdown() throws Exception {
    final UUID uuid = UUID.randomUUID();
    final SingleLeaderElectionService service = new SingleLeaderElectionService(executor, uuid);
    // create a leader contender and let it grab leadership
    final LeaderContender contender = mockContender(service);
    service.start(contender);
    verify(contender, times(1)).grantLeadership(uuid);
    // some leader listeners
    final LeaderRetrievalListener listener1 = mock(LeaderRetrievalListener.class);
    final LeaderRetrievalListener listener2 = mock(LeaderRetrievalListener.class);
    LeaderRetrievalService listenerService1 = service.createLeaderRetrievalService();
    LeaderRetrievalService listenerService2 = service.createLeaderRetrievalService();
    listenerService1.start(listener1);
    listenerService2.start(listener2);
    // one listener stops
    listenerService1.stop();
    // shut down the service
    service.shutdown();
    // the leader contender and running listener should get error notifications
    verify(contender, times(1)).handleError(any(Exception.class));
    verify(listener2, times(1)).handleError(any(Exception.class));
    // the stopped listener gets no notification
    verify(listener1, times(0)).handleError(any(Exception.class));
    // should not be possible to start again after shutdown
    try {
        service.start(contender);
        fail("should fail with an exception");
    } catch (IllegalStateException e) {
    // expected
    }
    // no additional leadership grant
    verify(contender, times(1)).grantLeadership(any(UUID.class));
}

Example 48 with UUID

use of java.util.UUID in project flink by apache.

the class SingleLeaderElectionServiceTest method mockContender.

private static LeaderContender mockContender(final LeaderElectionService service, final String address) {
    LeaderContender mockContender = mock(LeaderContender.class);
    when(mockContender.getAddress()).thenReturn(address);
    doAnswer(new Answer<Void>() {

        @Override
        public Void answer(InvocationOnMock invocation) throws Throwable {
            final UUID uuid = (UUID) invocation.getArguments()[0];
            service.confirmLeaderSessionID(uuid);
            return null;
        }
    }).when(mockContender).grantLeadership(any(UUID.class));
    return mockContender;
}

Example 49 with UUID

use of java.util.UUID in project flink by apache.

the class SingleLeaderElectionServiceTest method testStartStopAssignLeadership.

// ------------------------------------------------------------------------
@Test
public void testStartStopAssignLeadership() throws Exception {
    final UUID uuid = UUID.randomUUID();
    final SingleLeaderElectionService service = new SingleLeaderElectionService(executor, uuid);
    final LeaderContender contender = mockContender(service);
    final LeaderContender otherContender = mockContender(service);
    service.start(contender);
    verify(contender, times(1)).grantLeadership(uuid);
    service.stop();
    verify(contender, times(1)).revokeLeadership();
    // start with a new contender - the old contender must not gain another leadership
    service.start(otherContender);
    verify(otherContender, times(1)).grantLeadership(uuid);
    verify(contender, times(1)).grantLeadership(uuid);
    verify(contender, times(1)).revokeLeadership();
}

Example 50 with UUID

use of java.util.UUID in project flink by apache.

the class SingleLeaderElectionServiceTest method testStopBeforeConfirmingLeadership.

@Test
public void testStopBeforeConfirmingLeadership() throws Exception {
    final UUID uuid = UUID.randomUUID();
    final SingleLeaderElectionService service = new SingleLeaderElectionService(executor, uuid);
    final LeaderContender contender = mock(LeaderContender.class);
    service.start(contender);
    verify(contender, times(1)).grantLeadership(uuid);
    service.stop();
    // because the leadership was never confirmed, there is no "revoke" call
    verifyNoMoreInteractions(contender);
}