content: package org.apache.lucene.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.
   */
  
  import java.io.IOException;
  
  /**
   * <p>Base class for Locking implementation.  {@link Directory} uses
   * instances of this class to implement locking.</p>
   *
   * <p>Note that there are some useful tools to verify that
   * your LockFactory is working correctly: {@link
   * VerifyingLockFactory}, {@link LockStressTest}, {@link
   * LockVerifyServer}.</p>
   *
   * @see LockVerifyServer
   * @see LockStressTest
   * @see VerifyingLockFactory
   */
  
  public abstract class LockFactory {
  
    protected String lockPrefix = null;
  
    /**
     * Set the prefix in use for all locks created in this
     * LockFactory.  This is normally called once, when a
     * Directory gets this LockFactory instance.  However, you
     * can also call this (after this instance is assigned to
     * a Directory) to override the prefix in use.  This
     * is helpful if you're running Lucene on machines that
     * have different mount points for the same shared
     * directory.
     */
    public void setLockPrefix(String lockPrefix) {
      this.lockPrefix = lockPrefix;
    }
  
    /**
     * Get the prefix in use for all locks created in this LockFactory.
     */
    public String getLockPrefix() {
      return this.lockPrefix;
    }
  
    /**
     * Return a new Lock instance identified by lockName.
     * @param lockName name of the lock to be created.
     */
    public abstract Lock makeLock(String lockName);
  
    /**
     * Attempt to clear (forcefully unlock and remove) the
     * specified lock.  Only call this at a time when you are
     * certain this lock is no longer in use.
     * @param lockName name of the lock to be cleared.
     */
    abstract public void clearLock(String lockName) throws IOException;
  }
  