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1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * The ASF licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *     http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.apache.commons.configuration2.sync;
18  
19  /**
20   * <p>
21   * An enumeration used by {@link SynchronizerSupport} to specify how an object is locked.
22   * </p>
23   * <p>
24   * The {@code SynchronizerSupport} interface allows locking an object. This can be done in different ways controlling
25   * the level of concurrency still possible with the object. One of the constants defined here can be passed in when
26   * calling the {@code lock()} method of a {@code SynchronizerSupport} object. (Note that at the end of the day it is up
27   * to a concrete implementation of {@link Synchronizer} how these lock modes are interpreted.)
28   * </p>
29   *
30   * @since 2.0
31   */
32  public enum LockMode {
33      /**
34       * Lock mode <em>READ</em>. The object is accessed in a read-only manner. Typically, this means that other read locks
35       * can be granted while concurrent writes are not permitted.
36       */
37      READ,
38  
39      /**
40       * Lock mode <em>WRITE</em>. The object is updated. This usually means that this object is exclusively locked. Attempts
41       * of other readers or writers will block until the current update operation is complete.
42       */
43      WRITE
44  }