/*
* 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.IOException;
/**
* Base class for file system based locking implementation.
* This class is explicitly checking that the passed {@link Directory}
* is an {@link FSDirectory}.
*/
public abstract class FSLockFactory extends LockFactory {
/** Returns the default locking implementation for this platform.
* This method currently returns always {@link NativeFSLockFactory}.
*/
public static final FSLockFactory getDefault() {
return NativeFSLockFactory.INSTANCE;
}
@Override
public final Lock obtainLock(Directory dir, String lockName) throws IOException {
if (!(dir instanceof FSDirectory)) {
throw new UnsupportedOperationException(getClass().getSimpleName() + " can only be used with FSDirectory subclasses, got: " + dir);
}
return obtainFSLock((FSDirectory) dir, lockName);
}
/**
* Implement this method to obtain a lock for a FSDirectory instance.
* @throws IOException if the lock could not be obtained.
*/
protected abstract Lock obtainFSLock(FSDirectory dir, String lockName) throws IOException;
}