| /* |
| * Copyright 2003-2010 the original author or authors. |
| * |
| * Licensed 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.codehaus.groovy.util; |
| |
| import java.util.concurrent.locks.AbstractQueuedSynchronizer; |
| |
| /** |
| * A bit simplified lock designed to be inherited by. |
| */ |
| public class LockableObject extends AbstractQueuedSynchronizer { |
| transient Thread owner; |
| |
| protected final boolean isHeldExclusively() { |
| return getState() != 0 && owner == Thread.currentThread(); |
| } |
| |
| public final void lock() { |
| if (compareAndSetState(0, 1)) |
| owner = Thread.currentThread(); |
| else |
| acquire(1); |
| } |
| |
| public final void unlock() { |
| release(1); |
| } |
| |
| protected final boolean tryAcquire(int acquires) { |
| final Thread current = Thread.currentThread(); |
| int c = getState(); |
| if (c == 0) { |
| if (compareAndSetState(0, acquires)) { |
| owner = current; |
| return true; |
| } |
| } |
| else if (current == owner) { |
| setState(c+ acquires); |
| return true; |
| } |
| return false; |
| } |
| |
| protected final boolean tryRelease(int releases) { |
| int c = getState() - releases; |
| if (Thread.currentThread() != owner) |
| throw new IllegalMonitorStateException(); |
| boolean free = false; |
| if (c == 0) { |
| free = true; |
| owner = null; |
| } |
| setState(c); |
| return free; |
| } |
| } |