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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  package org.apache.hadoop.hbase;
21  
22  import org.apache.hadoop.classification.InterfaceAudience;
23  
24  /**
25   * An interface for a distributed reader-writer lock.
26   */
27  @InterfaceAudience.Private
28  public interface InterProcessReadWriteLock {
29  
30    /**
31     * Obtain a read lock containing given metadata.
32     * @param metadata Serialized lock metadata (this may contain information
33     *                 such as the process owning the lock or the purpose for
34     *                 which the lock was acquired).
35     * @return An instantiated InterProcessLock instance
36     */
37    InterProcessLock readLock(byte[] metadata);
38  
39    /**
40     * Obtain a write lock containing given metadata.
41     * @param metadata Serialized lock metadata (this may contain information
42     *                 such as the process owning the lock or the purpose for
43     *                 which the lock was acquired).
44     * @return An instantiated InterProcessLock instance
45     */
46    InterProcessLock writeLock(byte[] metadata);
47  }