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.File;
  
  /**
   * Base class for file system based locking implementation.
   */
  
  public abstract class FSLockFactory extends LockFactory {
  
    /**
     * Directory for the lock files.
     */
    protected File lockDir = null;
  
    /**
     * Set the lock directory. This method can be only called
     * once to initialize the lock directory. It is used by {@link FSDirectory}
     * to set the lock directory to itself.
     * Subclasses can also use this method to set the directory
     * in the constructor.
     */
    protected final void setLockDir(File lockDir) {
      if (this.lockDir != null)
        throw new IllegalStateException("You can set the lock directory for this factory only once.");
      this.lockDir = lockDir;
    }
    
    /**
     * Retrieve the lock directory.
     */
    public File getLockDir() {
      return lockDir;
    }
  
  }
  