1
package org.apache.lucene.store;
4
* Licensed to the Apache Software Foundation (ASF) under one or more
5
* contributor license agreements. See the NOTICE file distributed with
6
* this work for additional information regarding copyright ownership.
7
* The ASF licenses this file to You under the Apache License, Version 2.0
8
* (the "License"); you may not use this file except in compliance with
9
* the License. You may obtain a copy of the License at
11
* http://www.apache.org/licenses/LICENSE-2.0
13
* Unless required by applicable law or agreed to in writing, software
14
* distributed under the License is distributed on an "AS IS" BASIS,
15
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
16
* See the License for the specific language governing permissions and
17
* limitations under the License.
20
import java.io.IOException;
21
import java.util.HashSet;
24
* Implements {@link LockFactory} for a single in-process instance,
25
* meaning all locking will take place through this one instance.
26
* Only use this {@link LockFactory} when you are certain all
27
* IndexReaders and IndexWriters for a given index are running
28
* against a single shared in-process Directory instance. This is
29
* currently the default locking for RAMDirectory.
34
public class SingleInstanceLockFactory extends LockFactory {
36
private HashSet<String> locks = new HashSet<String>();
39
public Lock makeLock(String lockName) {
40
// We do not use the LockPrefix at all, because the private
41
// HashSet instance effectively scopes the locking to this
42
// single Directory instance.
43
return new SingleInstanceLock(locks, lockName);
47
public void clearLock(String lockName) throws IOException {
49
if (locks.contains(lockName)) {
50
locks.remove(lockName);
56
class SingleInstanceLock extends Lock {
59
private HashSet<String> locks;
61
public SingleInstanceLock(HashSet<String> locks, String lockName) {
63
this.lockName = lockName;
67
public boolean obtain() throws IOException {
69
return locks.add(lockName);
74
public void release() {
76
locks.remove(lockName);
81
public boolean isLocked() {
83
return locks.contains(lockName);
88
public String toString() {
89
return super.toString() + ": " + lockName;