001/*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements.  See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License.  You may obtain a copy of the License at
008 *
009 *     http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017package org.apache.commons.configuration2.sync;
018
019/**
020 * <p>
021 * An enumeration used by {@link SynchronizerSupport} to specify how an object is locked.
022 * </p>
023 * <p>
024 * The {@code SynchronizerSupport} interface allows locking an object. This can be done in different ways controlling
025 * the level of concurrency still possible with the object. One of the constants defined here can be passed in when
026 * calling the {@code lock()} method of a {@code SynchronizerSupport} object. (Note that at the end of the day it is up
027 * to a concrete implementation of {@link Synchronizer} how these lock modes are interpreted.)
028 * </p>
029 *
030 * @since 2.0
031 */
032public enum LockMode {
033    /**
034     * Lock mode <em>READ</em>. The object is accessed in a read-only manner. Typically, this means that other read locks
035     * can be granted while concurrent writes are not permitted.
036     */
037    READ,
038
039    /**
040     * Lock mode <em>WRITE</em>. The object is updated. This usually means that this object is exclusively locked. Attempts
041     * of other readers or writers will block until the current update operation is complete.
042     */
043    WRITE
044}