| /* |
| * Licensed to the Apache Software Foundation (ASF) under one or more |
| * contributor license agreements. See the NOTICE file distributed with |
| * this work for additional information regarding copyright ownership. |
| * The ASF licenses this file to You under the Apache License, Version 2.0 |
| * (the "License"); you may not use this file except in compliance with |
| * the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| package org.apache.lucene.store; |
| |
| |
| import java.io.IOException; |
| |
| /** |
| * <p>Base class for Locking implementation. {@link Directory} uses |
| * instances of this class to implement locking.</p> |
| * |
| * <p>Lucene uses {@link NativeFSLockFactory} by default for |
| * {@link FSDirectory}-based index directories.</p> |
| * |
| * <p>Special care needs to be taken if you change the locking |
| * implementation: First be certain that no writer is in fact |
| * writing to the index otherwise you can easily corrupt |
| * your index. Be sure to do the LockFactory change on all Lucene |
| * instances and clean up all leftover lock files before starting |
| * the new configuration for the first time. Different implementations |
| * can not work together!</p> |
| * |
| * <p>If you suspect that some LockFactory implementation is |
| * not working properly in your environment, you can easily |
| * test it by using {@link VerifyingLockFactory}, {@link |
| * LockVerifyServer} and {@link LockStressTest}.</p> |
| * |
| * @see LockVerifyServer |
| * @see LockStressTest |
| * @see VerifyingLockFactory |
| */ |
| |
| public abstract class LockFactory { |
| |
| /** |
| * Return a new obtained Lock instance identified by lockName. |
| * @param lockName name of the lock to be created. |
| * @throws LockObtainFailedException (optional specific exception) if the lock could |
| * not be obtained because it is currently held elsewhere. |
| * @throws IOException if any i/o error occurs attempting to gain the lock |
| */ |
| public abstract Lock obtainLock(Directory dir, String lockName) throws IOException; |
| |
| } |