Java 类com.datastax.driver.core.policies.LatencyAwarePolicy 实例源码

static Cluster buildCluster(Cassandra3Storage cassandra) {
  Cluster.Builder builder = Cluster.builder();
  List<InetSocketAddress> contactPoints = parseContactPoints(cassandra);
  int defaultPort = findConnectPort(contactPoints);
  builder.addContactPointsWithPorts(contactPoints);
  builder.withPort(defaultPort); // This ends up protocolOptions.port
  if (cassandra.username != null && cassandra.password != null) {
    builder.withCredentials(cassandra.username, cassandra.password);
  }
  builder.withRetryPolicy(ZipkinRetryPolicy.INSTANCE);
  builder.withLoadBalancingPolicy(new TokenAwarePolicy(new LatencyAwarePolicy.Builder(
      cassandra.localDc != null
          ? DCAwareRoundRobinPolicy.builder().withLocalDc(cassandra.localDc).build()
          : new RoundRobinPolicy()
      // This can select remote, but LatencyAwarePolicy will prefer local
  ).build()));
  builder.withPoolingOptions(new PoolingOptions().setMaxConnectionsPerHost(
      HostDistance.LOCAL, cassandra.maxConnections
  ));
  return builder.build();
}

static Cluster buildCluster(CassandraStorage cassandra) {
  Cluster.Builder builder = Cluster.builder();
  List<InetSocketAddress> contactPoints = parseContactPoints(cassandra);
  int defaultPort = findConnectPort(contactPoints);
  builder.addContactPointsWithPorts(contactPoints);
  builder.withPort(defaultPort); // This ends up protocolOptions.port
  if (cassandra.username != null && cassandra.password != null) {
    builder.withCredentials(cassandra.username, cassandra.password);
  }
  builder.withRetryPolicy(ZipkinRetryPolicy.INSTANCE);
  builder.withLoadBalancingPolicy(new TokenAwarePolicy(new LatencyAwarePolicy.Builder(
      cassandra.localDc != null
          ? DCAwareRoundRobinPolicy.builder().withLocalDc(cassandra.localDc).build()
          : new RoundRobinPolicy()
      // This can select remote, but LatencyAwarePolicy will prefer local
  ).build()));
  builder.withPoolingOptions(new PoolingOptions().setMaxConnectionsPerHost(
      HostDistance.LOCAL, cassandra.maxConnections
  ));
  return builder.build();
}

@Override
public LoadBalancingPolicy build() {
    LatencyAwarePolicy.Builder builder = LatencyAwarePolicy.builder(subPolicy.build());

    if (exclusionThreshold != null) {
        builder.withExclusionThreshold(exclusionThreshold);
    }

    if (minimumMeasurements != null) {
        builder.withMininumMeasurements(minimumMeasurements);
    }

    if (retryPeriod != null) {
        builder.withRetryPeriod(retryPeriod.getQuantity(), retryPeriod.getUnit());
    }

    if (scale != null) {
        builder.withScale(scale.getQuantity(), scale.getUnit());
    }

    if (updateRate != null) {
        builder.withUpdateRate(updateRate.getQuantity(), updateRate.getUnit());
    }

    return builder.build();
}

RoundRobinPolicy toRoundRobinPolicy(Cassandra3Storage storage) {
  return (RoundRobinPolicy) ((LatencyAwarePolicy) ((TokenAwarePolicy) buildCluster(storage)
      .getConfiguration()
      .getPolicies()
      .getLoadBalancingPolicy())
      .getChildPolicy()).getChildPolicy();
}

DCAwareRoundRobinPolicy toDCAwareRoundRobinPolicy(Cassandra3Storage storage) {
  return (DCAwareRoundRobinPolicy) ((LatencyAwarePolicy) ((TokenAwarePolicy) buildCluster(storage)
      .getConfiguration()
      .getPolicies()
      .getLoadBalancingPolicy())
      .getChildPolicy()).getChildPolicy();
}

RoundRobinPolicy toRoundRobinPolicy(CassandraStorage storage) {
  return (RoundRobinPolicy) ((LatencyAwarePolicy) ((TokenAwarePolicy) buildCluster(storage)
      .getConfiguration()
      .getPolicies()
      .getLoadBalancingPolicy())
      .getChildPolicy()).getChildPolicy();
}

DCAwareRoundRobinPolicy toDCAwareRoundRobinPolicy(CassandraStorage storage) {
  return (DCAwareRoundRobinPolicy) ((LatencyAwarePolicy) ((TokenAwarePolicy) buildCluster(storage)
      .getConfiguration()
      .getPolicies()
      .getLoadBalancingPolicy())
      .getChildPolicy()).getChildPolicy();
}

@Test
public void testLoadBalancingPolicyParsing() throws Exception
{
    String lbPolicyStr = "RoundRobinPolicy()";
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr) instanceof RoundRobinPolicy);
    System.out.println("====================");
    lbPolicyStr = "TokenAwarePolicy(RoundRobinPolicy())";
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr) instanceof TokenAwarePolicy);
    System.out.println("====================");
    lbPolicyStr = "DCAwareRoundRobinPolicy(\"dc1\")";
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr) instanceof DCAwareRoundRobinPolicy);
    System.out.println("====================");
    lbPolicyStr = "TokenAwarePolicy(DCAwareRoundRobinPolicy(\"dc1\"))";
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr) instanceof TokenAwarePolicy);       
    System.out.println("====================");
    lbPolicyStr = "TokenAwarePolicy";
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr)==null);
    System.out.println("====================");
    lbPolicyStr = "LatencyAwarePolicy(TokenAwarePolicy(RoundRobinPolicy()),(double) 10.5,(long) 1,(long) 10,(long)1,10)";       
    System.out.println(lbPolicyStr);
    assertTrue(Utils.parseLbPolicy(lbPolicyStr) instanceof LatencyAwarePolicy);
    System.out.println("====================");             

}

@Before
public void setUp() throws Exception {
    when(subPolicyFactory.build()).thenReturn(subPolicy);
    mockStatic(LatencyAwarePolicy.class);
    when(LatencyAwarePolicy.builder(subPolicy)).thenReturn(policyBuilder);
    when(policyBuilder.build()).thenReturn(resultingPolicy);
}

private static Cluster build(List<String> addresses, int port) {
  Cluster.Builder builder = Cluster.builder();
  for (String address : addresses) {
    builder.addContactPoint(address);
  }
  builder
    .withPort(port)
    .withCompression(Compression.LZ4)
    .withRetryPolicy(DowngradingConsistencyRetryPolicy.INSTANCE)
    .withLoadBalancingPolicy(LatencyAwarePolicy.builder(new RoundRobinPolicy()).build());

  Cluster cluster = builder.build();

  try {
    // Attempt to init the cluster to make sure it's usable. I'd prefer to remove this and leave it on the
    // client to retry when the connect method throws an exception.
    cluster.init();
    return cluster;
  } catch(NoHostAvailableException e) {
    LOGGER.warn("Unable to connect to Cassandra, will retry contact points next time",
        cluster, e);
    cluster = builder.build();
    cluster.init();
  }

  return cluster;

}