blob: 505ea6c195e04a32b7d17e9e7b5f0d228ecbe24b [file] [log] [blame]
// Copyright 2015 Google Inc. All rights reserved.
//
// 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 com.google.devtools.build.lib.concurrent;
import com.google.common.util.concurrent.Striped;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.locks.Lock;
/**
* An implementation of {@link KeyedLocker} backed by a {@link Striped}.
*/
public class StripedKeyedLocker<K> implements KeyedLocker<K> {
private final Striped<Lock> locks;
public StripedKeyedLocker(int stripes) {
locks = Striped.lock(stripes);
}
@Override
public AutoUnlocker lock(final K key) {
final Lock lock = locks.get(key);
lock.lock();
return new AutoUnlocker() {
private final AtomicBoolean closeCalled = new AtomicBoolean(false);
@Override
public void close() {
if (closeCalled.getAndSet(true)) {
String msg = String.format("For key %s, 'close' can be called at most once per "
+ "AutoUnlocker instance", key);
throw new IllegalUnlockException(msg);
}
lock.unlock();
}
};
}
}