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 package org.apache.hadoop.hbase.zookeeper.lock;
21
22 import org.apache.hadoop.hbase.classification.InterfaceAudience;
23 import org.apache.hadoop.hbase.InterProcessLock.MetadataHandler;
24 import org.apache.hadoop.hbase.InterProcessReadWriteLock;
25 import org.apache.hadoop.hbase.zookeeper.ZooKeeperWatcher;
26
27 /**
28 * ZooKeeper based implementation of {@link InterProcessReadWriteLock}. This lock is fair,
29 * not reentrant, and not revocable.
30 */
31 @InterfaceAudience.Private
32 public class ZKInterProcessReadWriteLock implements InterProcessReadWriteLock {
33
34 private final ZooKeeperWatcher zkWatcher;
35 private final String znode;
36 private final MetadataHandler handler;
37
38 /**
39 * Creates a DistributedReadWriteLock instance.
40 * @param zkWatcher
41 * @param znode ZNode path for the lock
42 * @param handler An object that will handle de-serializing and processing
43 * the metadata associated with reader or writer locks
44 * created by this object or null if none desired.
45 */
46 public ZKInterProcessReadWriteLock(ZooKeeperWatcher zkWatcher, String znode,
47 MetadataHandler handler) {
48 this.zkWatcher = zkWatcher;
49 this.znode = znode;
50 this.handler = handler;
51 }
52
53 /**
54 * {@inheritDoc}
55 */
56 public ZKInterProcessReadLock readLock(byte[] metadata) {
57 return new ZKInterProcessReadLock(zkWatcher, znode, metadata, handler);
58 }
59
60 /**
61 * {@inheritDoc}
62 */
63 public ZKInterProcessWriteLock writeLock(byte[] metadata) {
64 return new ZKInterProcessWriteLock(zkWatcher, znode, metadata, handler);
65 }
66 }