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.loadbalancing;

Determines how the driver will manage connections to a Cassandra node.

The distance is assigned by a LoadBalancingPolicy. 
/**
 * Determines how the driver will manage connections to a Cassandra node.
 *
 * <p>The distance is assigned by a {@link LoadBalancingPolicy}.
 */
public enum NodeDistance {
  
An "active" distance that, indicates that the driver should maintain connections to the node;
it also marks it as "preferred", meaning that the number or capacity of the connections may be
higher, and that the node may also have priority for some tasks (for example, being chosen as
the control host).

/**
   * An "active" distance that, indicates that the driver should maintain connections to the node;
   * it also marks it as "preferred", meaning that the number or capacity of the connections may be
   * higher, and that the node may also have priority for some tasks (for example, being chosen as
   * the control host).
   */
  LOCAL,
  
An "active" distance that, indicates that the driver should maintain connections to the node;
it also marks it as "less preferred", meaning that the number or capacity of the connections
may be lower, and that other nodes may have a higher priority for some tasks (for example,
being chosen as the control host).

/**
   * An "active" distance that, indicates that the driver should maintain connections to the node;
   * it also marks it as "less preferred", meaning that the number or capacity of the connections
   * may be lower, and that other nodes may have a higher priority for some tasks (for example,
   * being chosen as the control host).
   */
  REMOTE,
  
An "inactive" distance, that indicates that the driver will not open any connection to the
node.

/**
   * An "inactive" distance, that indicates that the driver will not open any connection to the
   * node.
   */
  IGNORED,
}