Java Policies类代码示例

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
/**
 * Derive the retry policy from the given string to the implementation. Defaults to {@link DefaultRetryPolicy}.
 * 
 * @param retryPolicy
 *            The name of the retry policy to use. Can be "downgrading" {@link DowngradingConsistencyRetryPolicy} or
 *            "fallthrough" {@link FallthroughRetryPolicy}. Everything else defaults to
 *            Policies.defaultRetryPolicy()
 */
public void setRetryPolicy(String retryPolicy) {
	switch(retryPolicy) {
		case "downgrading":
			setRetryPolicy(DowngradingConsistencyRetryPolicy.INSTANCE);
			break;

		case "fallthrough":
			setRetryPolicy(FallthroughRetryPolicy.INSTANCE);
			break;

		default:
			setRetryPolicy(Policies.defaultRetryPolicy());
			break;
	}
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
/**
 * Set the reconnection policy to define how often and in what interval to retry setup connections.
 * 
 * @param policy
 *            The reconnection policy as string "constant" {@link ConstantReconnectionPolicy} or "exponential"
 *            {@link ExponentialReconnectionPolicy}
 * @param delay
 *            The initial or constant delay
 * @param max
 *            The maximum delay (only required for {@link ExponentialReconnectionPolicy})
 */
public void setReconnectionPolicy(String policy, int delay, int... max) {
	switch(policy) {
		case "constant":
			setReconnectionPolicy(new ConstantReconnectionPolicy(delay));
			break;

		case "exponential":
			setReconnectionPolicy(new ExponentialReconnectionPolicy(delay, max[0]));
			break;

		default:
			setReconnectionPolicy(Policies.defaultReconnectionPolicy());
			break;
	}
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
@Test
public void shouldCreateClusterWithConfig() throws Exception {

	CassandraServiceInfo info = new CassandraServiceInfo("local",
			Collections.singletonList("127.0.0.1"), 9142);

	CassandraClusterConfig config = new CassandraClusterConfig();
	config.setCompression(ProtocolOptions.Compression.NONE);
	config.setPoolingOptions(new PoolingOptions().setPoolTimeoutMillis(1234));
	config.setQueryOptions(new QueryOptions());
	config.setProtocolVersion(ProtocolVersion.NEWEST_SUPPORTED);
	config.setLoadBalancingPolicy(new RoundRobinPolicy());
	config.setReconnectionPolicy(new ConstantReconnectionPolicy(1));
	config.setRetryPolicy(DowngradingConsistencyRetryPolicy.INSTANCE);
	config.setSocketOptions(new SocketOptions());

	Cluster cluster = creator.create(info, config);

	Configuration configuration = cluster.getConfiguration();

	assertThat(configuration.getProtocolOptions().getCompression(),
			is(config.getCompression()));
	assertThat(configuration.getQueryOptions(), is(config.getQueryOptions()));
	assertThat(configuration.getSocketOptions(), is(config.getSocketOptions()));

	Policies policies = configuration.getPolicies();
	assertThat(policies.getLoadBalancingPolicy(),
			is(config.getLoadBalancingPolicy()));
	assertThat(policies.getReconnectionPolicy(), is(config.getReconnectionPolicy()));
	assertThat(policies.getRetryPolicy(), is(config.getRetryPolicy()));
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
private com.datastax.driver.core.Cluster.Builder newCqlDriverBuilder(ConnectionPoolConfiguration poolConfig,
                                                                     MetricRegistry metricRegistry) {
    performHostDiscovery(metricRegistry);

    String[] seeds = _seeds.split(",");
    List<String> contactPoints = Lists.newArrayListWithCapacity(seeds.length);

    // Each seed may be a host name or a host name and port (e.g.; "1.2.3.4" or "1.2.3.4:9160").  These need
    // to be converted into host names only.
    for (String seed : seeds) {
        HostAndPort hostAndPort = HostAndPort.fromString(seed);
        seed = hostAndPort.getHostText();
        if (hostAndPort.hasPort()) {
            if (hostAndPort.getPort() == _thriftPort) {
                _log.debug("Seed {} found using RPC port; swapping for native port {}", seed, _cqlPort);
            } else if (hostAndPort.getPort() != _cqlPort) {
                throw new IllegalArgumentException(String.format(
                        "Seed %s found with invalid port %s.  The port must match either the RPC (thrift) port %s " +
                        "or the native (CQL) port %s", seed, hostAndPort.getPort(), _thriftPort, _cqlPort));
            }
        }

        contactPoints.add(seed);
    }

    PoolingOptions poolingOptions = new PoolingOptions();
    if (poolConfig.getMaxConnectionsPerHost().or(getMaxConnectionsPerHost()).isPresent()) {
        poolingOptions.setMaxConnectionsPerHost(HostDistance.LOCAL, poolConfig.getMaxConnectionsPerHost().or(getMaxConnectionsPerHost()).get());
    }
    if (poolConfig.getCoreConnectionsPerHost().or(getCoreConnectionsPerHost()).isPresent()) {
        poolingOptions.setCoreConnectionsPerHost(HostDistance.LOCAL, poolConfig.getCoreConnectionsPerHost().or(getCoreConnectionsPerHost()).get());
    }

    SocketOptions socketOptions = new SocketOptions();
    if (poolConfig.getConnectTimeout().or(getConnectTimeout()).isPresent()) {
        socketOptions.setConnectTimeoutMillis(poolConfig.getConnectTimeout().or(getConnectTimeout()).get());
    }
    if (poolConfig.getSocketTimeout().or(getSocketTimeout()).isPresent()) {
        socketOptions.setReadTimeoutMillis(poolConfig.getSocketTimeout().or(getSocketTimeout()).get());
    }

    AuthProvider authProvider = _authenticationCredentials != null
            ? new PlainTextAuthProvider(_authenticationCredentials.getUsername(), _authenticationCredentials.getPassword())
            : AuthProvider.NONE;

    return com.datastax.driver.core.Cluster.builder()
            .addContactPoints(contactPoints.toArray(new String[contactPoints.size()]))
            .withPort(_cqlPort)
            .withPoolingOptions(poolingOptions)
            .withSocketOptions(socketOptions)
            .withRetryPolicy(Policies.defaultRetryPolicy())
            .withAuthProvider(authProvider);
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
@BeforeClass()
public static void setup() throws ConfigurationException, IOException
{
    Schema.instance.clear();

    cassandra = new EmbeddedCassandraService();
    cassandra.start();

    cluster = Cluster.builder().addContactPoint("127.0.0.1")
                     .withRetryPolicy(new LoggingRetryPolicy(Policies.defaultRetryPolicy()))
                     .withPort(DatabaseDescriptor.getNativeTransportPort()).build();
    session = cluster.connect();

    session.execute("CREATE KEYSPACE IF NOT EXISTS " + KEYSPACE +" WITH replication " +
                    "= {'class':'SimpleStrategy', 'replication_factor':1};");
    session.execute("USE " + KEYSPACE);
    session.execute("CREATE TABLE IF NOT EXISTS " + TABLE + " (" +
                     "key blob," +
                     "value blob," +
                     "PRIMARY KEY (key));");


    // Prepared statements
    getStatement = session.prepare("SELECT value FROM " + TABLE + " WHERE key = ?;");
    getStatement.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);

    putStatement = session.prepare("INSERT INTO " + TABLE + " (key, value) VALUES (?, ?);");
    putStatement.setConsistencyLevel(ConsistencyLevel.LOCAL_QUORUM);



    StringBuilder s = new StringBuilder();
    char a='a';
    char z='z';
    for (int i = 0; i < 500*1024; i++)
    {
        char x = (char)((i%((z-a)+1))+a);
        if (x == 'a')
        {
            x = '\n';
        }
        s.append(x);
    }
    VALUE = s.toString();
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
public Policies getPolicies() {
	return policies;
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
public void setPolicies(Policies policies) {
	this.policies = policies;
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
/**
 * @return the policiesBuilder
 */
public Policies.Builder getPoliciesBuilder() {
	return policiesBuilder;
}
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
public synchronized Cluster buildCluster(){

        ConsistencyLevel defaultConsistencyLevel;
        try {
            defaultConsistencyLevel = cassandraConfig.getDataStaxReadCl();
        } catch (IllegalArgumentException e){

            logger.error("Unable to parse provided consistency level in property: {}, defaulting to: {}",
                CassandraFig.READ_CL,
                ConsistencyLevel.LOCAL_QUORUM);

            defaultConsistencyLevel = ConsistencyLevel.LOCAL_QUORUM;
        }


        LoadBalancingPolicy loadBalancingPolicy;
        if( !cassandraConfig.getLocalDataCenter().isEmpty() ){

            loadBalancingPolicy = new DCAwareRoundRobinPolicy.Builder()
                .withLocalDc( cassandraConfig.getLocalDataCenter() ).build();
        }else{
            loadBalancingPolicy = new DCAwareRoundRobinPolicy.Builder().build();
        }

        final PoolingOptions poolingOptions = new PoolingOptions()
            .setCoreConnectionsPerHost(HostDistance.LOCAL, cassandraConfig.getConnections())
            .setMaxConnectionsPerHost(HostDistance.LOCAL, cassandraConfig.getConnections())
            .setIdleTimeoutSeconds( cassandraConfig.getPoolTimeout() / 1000 )
            .setPoolTimeoutMillis( cassandraConfig.getPoolTimeout());

        // purposely add a couple seconds to the driver's lower level socket timeouts vs. cassandra timeouts
        final SocketOptions socketOptions = new SocketOptions()
            .setConnectTimeoutMillis( cassandraConfig.getTimeout())
            .setReadTimeoutMillis( cassandraConfig.getTimeout())
            .setKeepAlive(true);

        final QueryOptions queryOptions = new QueryOptions()
            .setConsistencyLevel(defaultConsistencyLevel)
            .setMetadataEnabled(true); // choose whether to have the driver store metadata such as schema info

        Cluster.Builder datastaxCluster = Cluster.builder()
            .withClusterName(cassandraConfig.getClusterName())
            .addContactPoints(cassandraConfig.getHosts().split(","))
            .withMaxSchemaAgreementWaitSeconds(45)
            .withCompression(ProtocolOptions.Compression.LZ4)
            .withLoadBalancingPolicy(loadBalancingPolicy)
            .withPoolingOptions(poolingOptions)
            .withQueryOptions(queryOptions)
            .withSocketOptions(socketOptions)
            .withReconnectionPolicy(Policies.defaultReconnectionPolicy())
            // client side timestamp generation is IMPORTANT; otherwise successive writes are left up to the server
            // to determine the ts and bad network delays, clock sync, etc. can result in bad behaviors
            .withTimestampGenerator(new AtomicMonotonicTimestampGenerator())
            .withProtocolVersion(getProtocolVersion(cassandraConfig.getVersion()));

        // only add auth credentials if they were provided
        if ( !cassandraConfig.getUsername().isEmpty() && !cassandraConfig.getPassword().isEmpty() ){
            datastaxCluster.withCredentials(
                cassandraConfig.getUsername(),
                cassandraConfig.getPassword()
            );
        }


        return datastaxCluster.build();

    }
 

import com.datastax.driver.core.policies.Policies; //导入依赖的package包/类
/**
 * @param policiesBuilder
 *            the policiesBuilder to set
 */
public void setPoliciesBuilder(Policies.Builder policiesBuilder) {
	this.policiesBuilder = policiesBuilder;
}