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.internal.core.loadbalancing.helper;

import com.datastax.oss.driver.api.core.loadbalancing.LoadBalancingPolicy;
import com.datastax.oss.driver.api.core.metadata.Node;
import edu.umd.cs.findbugs.annotations.NonNull;
import edu.umd.cs.findbugs.annotations.Nullable;
import java.util.Map;
import java.util.UUID;
import java.util.function.Predicate;
import net.jcip.annotations.ThreadSafe;

@FunctionalInterface
@ThreadSafe
public interface NodeFilterHelper {

  Predicate<Node> INCLUDE_ALL_NODES = n -> true;

  
Creates a new node filter.

Params:
  • localDc – The local datacenter, or null if none defined.
  • nodes – All the nodes that were known to exist in the cluster (regardless of their state) when the load balancing policy was initialized. This argument is provided in case implementors need to inspect the cluster topology to create the node filter.
Returns:the node filter to use.
/**
   * Creates a new node filter.
   *
   * @param localDc The local datacenter, or null if none defined.
   * @param nodes All the nodes that were known to exist in the cluster (regardless of their state)
   *     when the load balancing policy was {@linkplain LoadBalancingPolicy#init(Map,
   *     LoadBalancingPolicy.DistanceReporter) initialized}. This argument is provided in case
   *     implementors need to inspect the cluster topology to create the node filter.
   * @return the node filter to use.
   */
  @NonNull
  Predicate<Node> createNodeFilter(@Nullable String localDc, @NonNull Map<UUID, Node> nodes);
}