1 /*
 2  * Copyright (c) 2021, Oracle and/or its affiliates. All rights reserved.
 3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 4  *
 5  * This code is free software; you can redistribute it and/or modify it
 6  * under the terms of the GNU General Public License version 2 only, as
 7  * published by the Free Software Foundation.  Oracle designates this
 8  * particular file as subject to the "Classpath" exception as provided
 9  * by Oracle in the LICENSE file that accompanied this code.
10  *
11  * This code is distributed in the hope that it will be useful, but WITHOUT
12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
14  * version 2 for more details (a copy is included in the LICENSE file that
15  * accompanied this code).
16  *
17  * You should have received a copy of the GNU General Public License version
18  * 2 along with this work; if not, write to the Free Software Foundation,
19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20  *
21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22  * or visit www.oracle.com if you need additional information or have any
23  * questions.
24  */
25 
26 package jdk.internal.misc;
27 
28 import java.util.concurrent.locks.ReentrantLock;
29 
30 /**
31  * A reentrant mutual exclusion lock for internal use. The lock does not
32  * implement {@link java.util.concurrent.locks.Lock} or extend {@link
33  * java.util.concurrent.locks.ReentrantLock} so that it can be used for
34  * special handling in the {@link java.io} classes.
35  */
36 
37 public class InternalLock {
38     private final ReentrantLock lock = new ReentrantLock();
39 
40     public InternalLock() { }
41 
42     public boolean tryLock() {
43         return lock.tryLock();
44     }
45 
46     public void lock() {
47         lock.lock();
48     }
49 
50     public void unlock() {
51         lock.unlock();
52     }
53 
54     public boolean isHeldByCurrentThread() {
55         return lock.isHeldByCurrentThread();
56     }
57 }