1 /**
2 *
3 * Licensed to the Apache Software Foundation (ASF) under one
4 * or more contributor license agreements. See the NOTICE file
5 * distributed with this work for additional information
6 * regarding copyright ownership. The ASF licenses this file
7 * to you under the Apache License, Version 2.0 (the
8 * "License"); you may not use this file except in compliance
9 * with the License. You may obtain a copy of the License at
10 *
11 * http://www.apache.org/licenses/LICENSE-2.0
12 *
13 * Unless required by applicable law or agreed to in writing, software
14 * distributed under the License is distributed on an "AS IS" BASIS,
15 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16 * See the License for the specific language governing permissions and
17 * limitations under the License.
18 */
19 package org.apache.hadoop.hbase.client;
20
21 import java.util.Arrays;
22 import java.util.Random;
23
24 import org.apache.hadoop.hbase.classification.InterfaceAudience;
25 import org.apache.hadoop.hbase.HConstants;
26
27 /**
28 * NonceGenerator implementation that uses client ID hash + random int as nonce group,
29 * and random numbers as nonces.
30 */
31 @InterfaceAudience.Private
32 public class PerClientRandomNonceGenerator implements NonceGenerator {
33 private final Random rdm = new Random();
34 private final long clientId;
35
36 public PerClientRandomNonceGenerator() {
37 byte[] clientIdBase = ClientIdGenerator.generateClientId();
38 this.clientId = (((long)Arrays.hashCode(clientIdBase)) << 32) + rdm.nextInt();
39 }
40
41 public long getNonceGroup() {
42 return this.clientId;
43 }
44
45 public long newNonce() {
46 long result = HConstants.NO_NONCE;
47 do {
48 result = rdm.nextLong();
49 } while (result == HConstants.NO_NONCE);
50 return result;
51 }
52 }