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Librares that make easier to solve data problems using Hadoop and higher level languages based on it.

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/**
 * 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 datafu.hourglass.jobs;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.Path;
import org.apache.log4j.Logger;

/**
 * Used to remove files from the file system when they are no longer needed.
 * 
 */
public class FileCleaner
{
  private final Logger log = Logger.getLogger(FileCleaner.class);
  
  private final Set garbage = new HashSet();
  private final FileSystem fs;
  
  public FileCleaner(FileSystem fs)
  {
    this.fs = fs;
  }
  
  /**
   * Add a path to be removed later.
   * 
   * @param path path to be removed later
   * @return added path
   */
  public Path add(Path path)
  {
    garbage.add(path);
    return path;
  }
  
  /**
   * Add a path to be removed later.
   * 
   * @param path path to be removed later
   * @return added path
   */
  public String add(String path)
  {
    garbage.add(new Path(path));
    return path;
  }
  
  /**
   * Removes added paths from the file system.
   * 
   * @throws IOException IOException
   */
  @SuppressWarnings("unchecked")
  public void clean() throws IOException
  {
    List sorted = new ArrayList(garbage);
    Collections.sort(sorted);
    for (Path p : sorted)
    {
      if (fs.exists(p))
      {
        log.info(String.format("Removing %s",p));
        fs.delete(p, true);
      }
    }
    garbage.clear();
  }
}