interface/thrift/gen-java/org/apache/cassandra/thrift/ConsistencyLevel.java

/**
 * Autogenerated by Thrift Compiler (0.9.1)
 *
 * DO NOT EDIT UNLESS YOU ARE SURE THAT YOU KNOW WHAT YOU ARE DOING
 *  @generated
 */
package org.apache.cassandra.thrift;
/*
 * 
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you 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,
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import java.util.Map;
import java.util.HashMap;
import org.apache.thrift.TEnum;

/**
 * The ConsistencyLevel is an enum that controls both read and write
 * behavior based on the ReplicationFactor of the keyspace.  The
 * different consistency levels have different meanings, depending on
 * if you're doing a write or read operation.
 * 
 * If W + R > ReplicationFactor, where W is the number of nodes to
 * block for on write, and R the number to block for on reads, you
 * will have strongly consistent behavior; that is, readers will
 * always see the most recent write. Of these, the most interesting is
 * to do QUORUM reads and writes, which gives you consistency while
 * still allowing availability in the face of node failures up to half
 * of <ReplicationFactor>. Of course if latency is more important than
 * consistency then you can use lower values for either or both.
 * 
 * Some ConsistencyLevels (ONE, TWO, THREE) refer to a specific number
 * of replicas rather than a logical concept that adjusts
 * automatically with the replication factor.  Of these, only ONE is
 * commonly used; TWO and (even more rarely) THREE are only useful
 * when you care more about guaranteeing a certain level of
 * durability, than consistency.
 * 
 * Write consistency levels make the following guarantees before reporting success to the client:
 *   ANY          Ensure that the write has been written once somewhere, including possibly being hinted in a non-target node.
 *   ONE          Ensure that the write has been written to at least 1 node's commit log and memory table
 *   TWO          Ensure that the write has been written to at least 2 node's commit log and memory table
 *   THREE        Ensure that the write has been written to at least 3 node's commit log and memory table
 *   QUORUM       Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes
 *   LOCAL_ONE    Ensure that the write has been written to 1 node within the local datacenter (requires NetworkTopologyStrategy)
 *   LOCAL_QUORUM Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes, within the local datacenter (requires NetworkTopologyStrategy)
 *   EACH_QUORUM  Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes in each datacenter (requires NetworkTopologyStrategy)
 *   ALL          Ensure that the write is written to <code>&lt;ReplicationFactor&gt;</code> nodes before responding to the client.
 * 
 * Read consistency levels make the following guarantees before returning successful results to the client:
 *   ANY          Not supported. You probably want ONE instead.
 *   ONE          Returns the record obtained from a single replica.
 *   TWO          Returns the record with the most recent timestamp once two replicas have replied.
 *   THREE        Returns the record with the most recent timestamp once three replicas have replied.
 *   QUORUM       Returns the record with the most recent timestamp once a majority of replicas have replied.
 *   LOCAL_ONE    Returns the record with the most recent timestamp once a single replica within the local datacenter have replied.
 *   LOCAL_QUORUM Returns the record with the most recent timestamp once a majority of replicas within the local datacenter have replied.
 *   EACH_QUORUM  Returns the record with the most recent timestamp once a majority of replicas within each datacenter have replied.
 *   ALL          Returns the record with the most recent timestamp once all replicas have replied (implies no replica may be down)..
 */
public enum ConsistencyLevel implements org.apache.thrift.TEnum {
  ONE(1),
  QUORUM(2),
  LOCAL_QUORUM(3),
  EACH_QUORUM(4),
  ALL(5),
  ANY(6),
  TWO(7),
  THREE(8),
  SERIAL(9),
  LOCAL_SERIAL(10),
  LOCAL_ONE(11);

  private final int value;

  private ConsistencyLevel(int value) {
    this.value = value;
  }

  /**
   * Get the integer value of this enum value, as defined in the Thrift IDL.
   */
  public int getValue() {
    return value;
  }

  /**
   * Find a the enum type by its integer value, as defined in the Thrift IDL.
   * @return null if the value is not found.
   */
  public static ConsistencyLevel findByValue(int value) { 
    switch (value) {
      case 1:
        return ONE;
      case 2:
        return QUORUM;
      case 3:
        return LOCAL_QUORUM;
      case 4:
        return EACH_QUORUM;
      case 5:
        return ALL;
      case 6:
        return ANY;
      case 7:
        return TWO;
      case 8:
        return THREE;
      case 9:
        return SERIAL;
      case 10:
        return LOCAL_SERIAL;
      case 11:
        return LOCAL_ONE;
      default:
        return null;
    }
  }
}