com.avanza.astrix.modules.KeyLock Maven / Gradle / Ivy
/*
* Copyright 2014 Avanza Bank AB
*
* 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.avanza.astrix.modules;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.locks.ReentrantLock;
public final class KeyLock {
private final ConcurrentMap lockedObjects = new ConcurrentHashMap<>();
private int size = 17;
/**
* Locks the given key.
*
* @param key
*/
public void lock(K key) {
ReentrantLock lock = getLock(key);
lock.lock();
}
/**
* Unlocks the given key
* @param key
*/
public void unlock(K key) {
ReentrantLock lock = getLock(key);
if (!lock.isHeldByCurrentThread()) {
throw new IllegalStateException("Cannot release lock not held by current thread: " + key);
}
lock.unlock();
}
private ReentrantLock getLock(K key) {
ReentrantLock lock = new ReentrantLock();
int lockId = key.hashCode() % size;
ReentrantLock existingLock = lockedObjects.putIfAbsent(lockId, lock);
if (existingLock != null) {
// Another thread is already created lock
lock = existingLock;
}
return lock;
}
}