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SingleInstanceLockFactory.cs
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SingleInstanceLockFactory.cs
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using Lucene.Net.Support.Threading;
using System.Collections.Generic;
using JCG = J2N.Collections.Generic;
namespace Lucene.Net.Store
{
/*
* 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.
*/
/// <summary>
/// Implements <see cref="LockFactory"/> for a single in-process instance,
/// meaning all locking will take place through this one instance.
/// Only use this <see cref="LockFactory"/> when you are certain all
/// <see cref="Index.IndexReader"/>s and <see cref="Index.IndexWriter"/>s for a given index are running
/// against a single shared in-process <see cref="Directory"/> instance. This is
/// currently the default locking for <see cref="RAMDirectory"/>.
/// </summary>
/// <seealso cref="LockFactory"/>
public class SingleInstanceLockFactory : LockFactory
{
private readonly JCG.HashSet<string> locks = new JCG.HashSet<string>(); // LUCENENET: marked readonly
public override Lock MakeLock(string lockName)
{
// We do not use the LockPrefix at all, because the private
// HashSet instance effectively scopes the locking to this
// single Directory instance.
return new SingleInstanceLock(locks, lockName);
}
public override void ClearLock(string lockName)
{
UninterruptableMonitor.Enter(locks);
try
{
if (locks.Contains(lockName))
{
locks.Remove(lockName);
}
}
finally
{
UninterruptableMonitor.Exit(locks);
}
}
}
internal class SingleInstanceLock : Lock
{
internal string lockName;
private readonly JCG.HashSet<string> locks;
public SingleInstanceLock(JCG.HashSet<string> locks, string lockName)
{
this.locks = locks;
this.lockName = lockName;
}
public override bool Obtain()
{
UninterruptableMonitor.Enter(locks);
try
{
return locks.Add(lockName);
}
finally
{
UninterruptableMonitor.Exit(locks);
}
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
UninterruptableMonitor.Enter(locks);
try
{
locks.Remove(lockName);
}
finally
{
UninterruptableMonitor.Exit(locks);
}
}
}
public override bool IsLocked()
{
UninterruptableMonitor.Enter(locks);
try
{
return locks.Contains(lockName);
}
finally
{
UninterruptableMonitor.Exit(locks);
}
}
public override string ToString()
{
return base.ToString() + ": " + lockName;
}
}
}