How to use

getDatacenter

method

in

com.datastax.driver.core.Host

/**
 * {@inheritDoc}
 */
@Override
public synchronized Session connect() throws NoHostAvailableException {
  if (isDisconnected()) {
    LOG.info("Connected to cluster: {}", cluster.getClusterName());
    for (Host host : getAllHosts())
      LOG.info("Datacenter: {}; Host: {}; Rack: {}", host.getDatacenter(), host.getAddress(), host.getRack());
    LOG.info("Connect to cluster using keyspace %s", keyspace);
    session = cluster.connect(keyspace);
  } else {
    LOG.warn("{} - Already connected to cluster: {}", getExecutorName(), cluster.getClusterName());
  }
  if (session.isClosed()) {
    LOG.warn("Session has been closed - create new one!");
    this.session = cluster.newSession();
  }
  return session;
}

  @Override
  public Cluster get() {
    String host = configuration.getHostAddress();
    int port = configuration.getPort();

    LOGGER.info("Connecting to cassandra cluster with host:{}, port:{}", host, port);

    Cluster cluster = Cluster.builder()
        .addContactPoint(host)
        .withPort(port)
        .build();

    Metadata metadata = cluster.getMetadata();
    LOGGER.info("Connected to cluster: {}", metadata.getClusterName());
    metadata.getAllHosts().forEach(h -> {
      LOGGER.info("Datacenter:{}, host:{}, rack: {}", h.getDatacenter(), h.getAddress(), h.getRack());
    });
    return cluster;
  }
}

discoveredHost.getDatacenter(), discoveredHost.getAddress(),
discoveredHost.getRack());

private String dc(Host host) {
 String dc = host.getDatacenter();
 return dc == null ? localDc : dc;
}

 @Override
 public boolean apply(Host host) {
  String hdc = host.getDatacenter();
  return (hdc == null) ? includeNullDC : _dcs.contains(hdc);
 }
};

private Map<String, Set<String>> getRacksInDcs(Iterable<Host> hosts) {
 Map<String, Set<String>> result = new HashMap<String, Set<String>>();
 for (Host host : hosts) {
  Set<String> racks = result.get(host.getDatacenter());
  if (racks == null) {
   racks = new HashSet<String>();
   result.put(host.getDatacenter(), racks);
  }
  racks.add(host.getRack());
 }
 return result;
}

public HostAssert isInDatacenter(String datacenter) {
 assertThat(actual.getDatacenter()).isEqualTo(datacenter);
 return this;
}

String dc = host.getDatacenter();
if (dcHostCount.get(dc) == null) {
 dcHostCount.put(dc, 0);
for (int j = 0; j < ring.size() && !allDone(allDcReplicas, dcHostCount); j++) {
 Host h = tokenToPrimary.get(getTokenWrapping(i + j, ring));
 String dc = h.getDatacenter();
 if (dc == null || !allDcReplicas.containsKey(dc)) continue;

@Test(groups = "unit")
public void should_ignore_DCs_in_black_list() {
 when(host1.getDatacenter()).thenReturn("dc1");
 when(host2.getDatacenter()).thenReturn("dc2");
 when(host3.getDatacenter()).thenReturn(null);
 HostFilterPolicy policy =
   HostFilterPolicy.fromDCBlackList(wrappedPolicy, Lists.newArrayList("dc2"));
 assertThat(policy.distance(host1)).isSameAs(HostDistance.LOCAL);
 assertThat(policy.distance(host2)).isSameAs(HostDistance.IGNORED);
 assertThat(policy.distance(host3)).isSameAs(HostDistance.LOCAL);
}

 @Test(groups = "unit")
 public void should_ignore_DCs_not_in_white_list_and_not_null() {
  when(host1.getDatacenter()).thenReturn("dc1");
  when(host2.getDatacenter()).thenReturn("dc2");
  when(host3.getDatacenter()).thenReturn(null);

  HostFilterPolicy policy =
    HostFilterPolicy.fromDCWhiteList(wrappedPolicy, Lists.newArrayList("dc1"));

  assertThat(policy.distance(host1)).isSameAs(HostDistance.LOCAL);
  assertThat(policy.distance(host2)).isSameAs(HostDistance.IGNORED);
  assertThat(policy.distance(host3)).isSameAs(HostDistance.LOCAL);
 }
}

private static void updateLocationInfo(
  Host host,
  String datacenter,
  String rack,
  boolean isInitialConnection,
  Cluster.Manager cluster) {
 if (MoreObjects.equal(host.getDatacenter(), datacenter)
   && MoreObjects.equal(host.getRack(), rack)) return;
 // If the dc/rack information changes for an existing node, we need to update the load balancing
 // policy.
 // For that, we remove and re-add the node against the policy. Not the most elegant, and assumes
 // that the policy will update correctly, but in practice this should work.
 if (!isInitialConnection) cluster.loadBalancingPolicy().onDown(host);
 host.setLocationInfo(datacenter, rack);
 if (!isInitialConnection) cluster.loadBalancingPolicy().onAdd(host);
}

private Map<String, Set<String>> getRacksInDcs(Iterable<Host> hosts) {
  Map<String, Set<String>> result = new HashMap<String, Set<String>>();
  for (Host host : hosts) {
    Set<String> racks = result.get(host.getDatacenter());
    if (racks == null) {
      racks = new HashSet<String>();
      result.put(host.getDatacenter(), racks);
    }
    racks.add(host.getRack());
  }
  return result;
}

assertThat(initHostsCaptor.getValue()).containsExactly(host1);
assertThat(policy.localDc).isEqualTo(host1.getDatacenter());

assertThat(initHostsCaptor.getValue()).containsOnly(host1);
assertThat(policy.localDc).isEqualTo(host1.getDatacenter());

private RingMember(Host host) {
  Assert.notNull(host, "Host must not be null");
  this.hostName = host.getAddress().getHostName();
  this.address = host.getAddress().getHostAddress();
  this.dc = host.getDatacenter();
  this.rack = host.getRack();
}

for (Host host : metadata.getAllHosts()) {
  LOGGER.info("Datatacenter: {}; Host: {}; Rack: {}\n",
      host.getDatacenter(),
      host.getAddress(),
      host.getRack());

private static void updateLocationInfo(Host host, String datacenter, String rack, Cluster.Manager cluster) {
  if (Objects.equal(host.getDatacenter(), datacenter) && Objects.equal(host.getRack(), rack))
    return;
  // If the dc/rack information changes, we need to update the load balancing policy.
  // For that, we remove and re-add the node against the policy. Not the most elegant, and assumes
  // that the policy will update correctly, but in practice this should work.
  cluster.loadBalancingPolicy().onDown(host);
  host.setLocationInfo(datacenter, rack);
  cluster.loadBalancingPolicy().onAdd(host);
}

 @Test(groups = "unit")
 public void should_ignore_DCs_not_in_white_list_and_not_null() {
  when(host1.getDatacenter()).thenReturn("dc1");
  when(host2.getDatacenter()).thenReturn("dc2");
  when(host3.getDatacenter()).thenReturn(null);

  HostFilterPolicy policy =
    HostFilterPolicy.fromDCWhiteList(wrappedPolicy, Lists.newArrayList("dc1"));

  assertThat(policy.distance(host1)).isSameAs(HostDistance.LOCAL);
  assertThat(policy.distance(host2)).isSameAs(HostDistance.IGNORED);
  assertThat(policy.distance(host3)).isSameAs(HostDistance.LOCAL);
 }
}

private static void updateLocationInfo(Host host, String datacenter, String rack, boolean isInitialConnection, Cluster.Manager cluster) {
  if (Objects.equal(host.getDatacenter(), datacenter) && Objects.equal(host.getRack(), rack))
    return;
  // If the dc/rack information changes for an existing node, we need to update the load balancing policy.
  // For that, we remove and re-add the node against the policy. Not the most elegant, and assumes
  // that the policy will update correctly, but in practice this should work.
  if (!isInitialConnection)
    cluster.loadBalancingPolicy().onDown(host);
  host.setLocationInfo(datacenter, rack);
  if (!isInitialConnection)
    cluster.loadBalancingPolicy().onAdd(host);
}

private static void updateLocationInfo(Host host, String datacenter, String rack, boolean isInitialConnection, Cluster.Manager cluster) {
  if (MoreObjects.equal(host.getDatacenter(), datacenter) && MoreObjects.equal(host.getRack(), rack))
    return;
  // If the dc/rack information changes for an existing node, we need to update the load balancing policy.
  // For that, we remove and re-add the node against the policy. Not the most elegant, and assumes
  // that the policy will update correctly, but in practice this should work.
  if (!isInitialConnection)
    cluster.loadBalancingPolicy().onDown(host);
  host.setLocationInfo(datacenter, rack);
  if (!isInitialConnection)
    cluster.loadBalancingPolicy().onAdd(host);
}