| package org.apache.lucene.store; |
| |
| /* |
| * 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. |
| */ |
| |
| import java.io.IOException; |
| import java.util.HashSet; |
| |
| /** |
| * Implements {@link LockFactory} for a single in-process instance, |
| * meaning all locking will take place through this one instance. |
| * Only use this {@link LockFactory} when you are certain all |
| * IndexReaders and IndexWriters for a given index are running |
| * against a single shared in-process Directory instance. This is |
| * currently the default locking for RAMDirectory. |
| * |
| * @see LockFactory |
| */ |
| |
| public class SingleInstanceLockFactory extends LockFactory { |
| |
| private HashSet<String> locks = new HashSet<>(); |
| |
| @Override |
| public Lock makeLock(String lockName) { |
| // We do not use the LockPrefix at all, because the private |
| // HashSet instance effectively scopes the locking to this |
| // single Directory instance. |
| return new SingleInstanceLock(locks, lockName); |
| } |
| |
| @Override |
| public void clearLock(String lockName) throws IOException { |
| synchronized(locks) { |
| if (locks.contains(lockName)) { |
| locks.remove(lockName); |
| } |
| } |
| } |
| } |
| |
| class SingleInstanceLock extends Lock { |
| |
| String lockName; |
| private HashSet<String> locks; |
| |
| public SingleInstanceLock(HashSet<String> locks, String lockName) { |
| this.locks = locks; |
| this.lockName = lockName; |
| } |
| |
| @Override |
| public boolean obtain() throws IOException { |
| synchronized(locks) { |
| return locks.add(lockName); |
| } |
| } |
| |
| @Override |
| public void close() { |
| synchronized(locks) { |
| locks.remove(lockName); |
| } |
| } |
| |
| @Override |
| public boolean isLocked() { |
| synchronized(locks) { |
| return locks.contains(lockName); |
| } |
| } |
| |
| @Override |
| public String toString() { |
| return super.toString() + ": " + lockName; |
| } |
| } |