/**
* Autogenerated by Thrift
*
* DO NOT EDIT UNLESS YOU ARE SURE THAT YOU KNOW WHAT YOU ARE DOING
*/
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,
* 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.
*
*/
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 <ReplicationFactor> in your
* storage-conf.xml. The different consistency levels have different meanings, depending on if you're doing a write or read
* operation. Note that 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.
*
* Write:
* ZERO Ensure nothing. A write happens asynchronously in background
* 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 before responding to the client.
* QUORUM Ensure that the write has been written to <ReplicationFactor> / 2 + 1 nodes before responding to the client.
* ALL Ensure that the write is written to <code><ReplicationFactor></code> nodes before responding to the client.
*
* Read:
* ZERO Not supported, because it doesn't make sense.
* ANY Not supported. You probably want ONE instead.
* ONE Will return the record returned by the first node to respond. A consistency check is always done in a
* background thread to fix any consistency issues when ConsistencyLevel.ONE is used. This means subsequent
* calls will have correct data even if the initial read gets an older value. (This is called 'read repair'.)
* QUORUM Will query all storage nodes and return the record with the most recent timestamp once it has at least a
* majority of replicas reported. Again, the remaining replicas will be checked in the background.
* ALL Not yet supported, but we plan to eventually.
*/
public enum ConsistencyLevel implements TEnum {
ZERO(0),
ONE(1),
QUORUM(2),
DCQUORUM(3),
DCQUORUMSYNC(4),
ALL(5),
ANY(6);
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 0:
return ZERO;
case 1:
return ONE;
case 2:
return QUORUM;
case 3:
return DCQUORUM;
case 4:
return DCQUORUMSYNC;
case 5:
return ALL;
case 6:
return ANY;
default:
return null;
}
}
}