https://github.com/datastax/java-driver/java-driver-core: A driver for Apache Cassandra(R) 2.1+ that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's native protocol versions 3 and above.
  • Various (DataStax) 
/*
 * Copyright DataStax, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.datastax.oss.driver.api.core.addresstranslation;

import edu.umd.cs.findbugs.annotations.NonNull;
import java.net.InetSocketAddress;


Translates IP addresses received from Cassandra nodes into locally queriable addresses.

The driver auto-detects new Cassandra nodes added to the cluster through server side pushed notifications and system table queries. For each node, the address the driver will receive will correspond to the address set as broadcast_rpc_address in the node's YAML file. In most cases, this is the correct address to use by the driver, and that is what is used by default. However, sometimes the addresses received through this mechanism will either not be reachable directly by the driver, or should not be the preferred address to use to reach the node (for instance, the broadcast_rpc_address set on Cassandra nodes might be a private IP, but some clients may have to use a public IP, or go through a router to reach that node). This interface addresses such cases, by allowing to translate an address as sent by a Cassandra node into another address to be used by the driver for connection. 
The contact point addresses provided at driver initialization are considered translated
already; in other words, they will be used as-is, without being processed by this component.

/**
 * Translates IP addresses received from Cassandra nodes into locally queriable addresses.
 *
 * <p>The driver auto-detects new Cassandra nodes added to the cluster through server side pushed
 * notifications and system table queries. For each node, the address the driver will receive will
 * correspond to the address set as {@code broadcast_rpc_address} in the node's YAML file. In most
 * cases, this is the correct address to use by the driver, and that is what is used by default.
 * However, sometimes the addresses received through this mechanism will either not be reachable
 * directly by the driver, or should not be the preferred address to use to reach the node (for
 * instance, the {@code broadcast_rpc_address} set on Cassandra nodes might be a private IP, but
 * some clients may have to use a public IP, or go through a router to reach that node). This
 * interface addresses such cases, by allowing to translate an address as sent by a Cassandra node
 * into another address to be used by the driver for connection.
 *
 * <p>The contact point addresses provided at driver initialization are considered translated
 * already; in other words, they will be used as-is, without being processed by this component.
 */
public interface AddressTranslator extends AutoCloseable {

  
Translates an address reported by a Cassandra node into the address that the driver will use to
connect.

/**
   * Translates an address reported by a Cassandra node into the address that the driver will use to
   * connect.
   */
  @NonNull
  InetSocketAddress translate(@NonNull InetSocketAddress address);

  
Called when the cluster that this translator is associated with closes. 
/** Called when the cluster that this translator is associated with closes. */
  @Override
  void close();
}