content: /**
   * 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.solr.core;
  
  import java.io.File;
  import java.io.IOException;
  import java.util.HashMap;
  import java.util.Map;
  
  import org.apache.lucene.store.Directory;
  
  /**
   * Directory provider for using lucene RAMDirectory
   */
  public class RAMDirectoryFactory extends StandardDirectoryFactory {
    private static Map<String, RefCntRamDirectory> directories = new HashMap<String, RefCntRamDirectory>();
  
    @Override
    public Directory open(String path) throws IOException {
      synchronized (RAMDirectoryFactory.class) {
        RefCntRamDirectory directory = directories.get(path);
        if (directory == null || !directory.isOpen()) {
          directory = (RefCntRamDirectory) openNew(path);
          directories.put(path, directory);
        } else {
          directory.incRef();
        }
  
        return directory;
      }
    }
    
    @Override
    public boolean exists(String path) {
      synchronized (RAMDirectoryFactory.class) {
        RefCntRamDirectory directory = directories.get(path);
        if (directory == null || !directory.isOpen()) {
          return false;
        } else {
          return true;
        }
      }
    }
  
    /**
     * Non-public for unit-test access only. Do not use directly
     */
    Directory openNew(String path) throws IOException {
      Directory directory;
      File dirFile = new File(path);
      boolean indexExists = dirFile.canRead();
      if (indexExists) {
        Directory dir = super.open(path);
        directory = new RefCntRamDirectory(dir);
      } else {
        directory = new RefCntRamDirectory();
      }
      return directory;
    }
  }
  