/*
* 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.lucene.store;
import java.io.Closeable;
import java.io.IOException;
/** An interprocess mutex lock.
* <p>Typical use might look like:<pre class="prettyprint">
* try (final Lock lock = directory.obtainLock("my.lock")) {
* // ... code to execute while locked ...
* }
* </pre>
*
* @see Directory#obtainLock(String)
*
* @lucene.internal
*/
public abstract class Lock implements Closeable {
/**
* Releases exclusive access.
* <p>
* Note that exceptions thrown from close may require
* human intervention, as it may mean the lock was no
* longer valid, or that fs permissions prevent removal
* of the lock file, or other reasons.
* <p>
* {@inheritDoc}
* @throws LockReleaseFailedException optional specific exception) if
* the lock could not be properly released.
*/
public abstract void close() throws IOException;
/**
* Best effort check that this lock is still valid. Locks
* could become invalidated externally for a number of reasons,
* for example if a user deletes the lock file manually or
* when a network filesystem is in use.
* @throws IOException if the lock is no longer valid.
*/
public abstract void ensureValid() throws IOException;
}