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1   /*
2    * Copyright The Apache Software Foundation
3    *
4    * Licensed to the Apache Software Foundation (ASF) under one
5    * or more contributor license agreements.  See the NOTICE file
6    * distributed with this work for additional information
7    * regarding copyright ownership.  The ASF licenses this file
8    * to you under the Apache License, Version 2.0 (the
9    * "License"); you may not use this file except in compliance
10   * with the License.  You may obtain a copy of the License at
11   *
12   *     http://www.apache.org/licenses/LICENSE-2.0
13   *
14   * Unless required by applicable law or agreed to in writing, software
15   * distributed under the License is distributed on an "AS IS" BASIS,
16   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
17   * See the License for the specific language governing permissions and
18   * limitations under the License.
19   */
20  
21  package org.apache.hadoop.hbase.client;
22  
23  import org.apache.hadoop.classification.InterfaceAudience;
24  import org.apache.hadoop.classification.InterfaceStability;
25  
26  /**
27   * Specify Isolation levels in Scan operations.
28   * <p>
29   * There are two isolation levels. A READ_COMMITTED isolation level
30   * indicates that only data that is committed be returned in a scan.
31   * An isolation level of READ_UNCOMMITTED indicates that a scan
32   * should return data that is being modified by transactions that might
33   * not have been committed yet.
34   */
35  @InterfaceAudience.Public
36  @InterfaceStability.Stable
37  public enum IsolationLevel {
38  
39    READ_COMMITTED(1),
40    READ_UNCOMMITTED(2);
41  
42    IsolationLevel(int value) {}
43  
44    public byte [] toBytes() {
45      return new byte [] { toByte() };
46    }
47  
48    public byte toByte() {
49      return (byte)this.ordinal();
50    }
51  
52    public static IsolationLevel fromBytes(byte [] bytes) {
53      return IsolationLevel.fromByte(bytes[0]);
54    }
55  
56    public static IsolationLevel fromByte(byte vbyte) {
57      return IsolationLevel.values()[vbyte];
58    }
59  }