/**
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you 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.apache.hadoop.hbase.util;
import java.util.concurrent.locks.ReentrantLock;
import org.apache.hadoop.hbase.testclassification.MiscTests;
import org.apache.hadoop.hbase.testclassification.SmallTests;
import org.junit.Assert;
import org.junit.Test;
import org.junit.experimental.categories.Category;
@Category({MiscTests.class, SmallTests.class})
public class TestKeyLocker {
@Test
public void testLocker(){
KeyLocker<String> locker = new KeyLocker<>();
ReentrantLock lock1 = locker.acquireLock("l1");
Assert.assertTrue(lock1.isHeldByCurrentThread());
ReentrantLock lock2 = locker.acquireLock("l2");
Assert.assertTrue(lock2.isHeldByCurrentThread());
Assert.assertTrue(lock1 != lock2);
// same key = same lock
ReentrantLock lock20 = locker.acquireLock("l2");
Assert.assertTrue(lock20 == lock2);
Assert.assertTrue(lock2.isHeldByCurrentThread());
Assert.assertTrue(lock20.isHeldByCurrentThread());
// Locks are still reentrant; so with 2 acquires we want two unlocks
lock20.unlock();
Assert.assertTrue(lock20.isHeldByCurrentThread());
lock2.unlock();
Assert.assertFalse(lock20.isHeldByCurrentThread());
// The lock object will be garbage-collected
// if you free its reference for a long time,
// and you will get a new one at the next time.
int lock2Hash = System.identityHashCode(lock2);
lock2 = null;
lock20 = null;
System.gc();
System.gc();
System.gc();
ReentrantLock lock200 = locker.acquireLock("l2");
Assert.assertNotEquals(lock2Hash, System.identityHashCode(lock200));
lock200.unlock();
Assert.assertFalse(lock200.isHeldByCurrentThread());
// first lock is still there
Assert.assertTrue(lock1.isHeldByCurrentThread());
lock1.unlock();
Assert.assertFalse(lock1.isHeldByCurrentThread());
}
}