code: /*
   * 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.commons.io.comparator;
  
  import java.io.File;
  import java.io.Serializable;
  import java.util.Comparator;
  
  /**
   * Compare two files using the {@link File#isDirectory()} method.
   * <p>
   * This comparator can be used to sort lists or arrays by directories and files.
   * <p>
   * Example of sorting a list of files/directories using the
   * {@link #DIRECTORY_COMPARATOR} singleton instance:
   * <pre>
   *       List&lt;File&gt; list = ...
   *       DirectoryFileComparator.DIRECTORY_COMPARATOR.sort(list);
   * </pre>
   * <p>
   * Example of doing a <i>reverse</i> sort of an array of files/directories using the
   * {@link #DIRECTORY_REVERSE} singleton instance:
   * <pre>
   *       File[] array = ...
   *       DirectoryFileComparator.DIRECTORY_REVERSE.sort(array);
   * </pre>
   * <p>
   *
   * @version $Revision: 1.1.2.1 $ $Date: 2011/01/15 20:32:24 $
   * @since Commons IO 2.0
   */
  public class DirectoryFileComparator extends AbstractFileComparator implements Serializable {
  
      /** Singleton default comparator instance */
      public static final Comparator<File> DIRECTORY_COMPARATOR = new DirectoryFileComparator();
  
      /** Singleton reverse default comparator instance */
      public static final Comparator<File> DIRECTORY_REVERSE = new ReverseComparator(DIRECTORY_COMPARATOR);
  
      /**
       * Compare the two files using the {@link File#isDirectory()} method.
       * 
       * @param file1 The first file to compare
       * @param file2 The second file to compare
       * @return the result of calling file1's
       * {@link File#compareTo(File)} with file2 as the parameter.
       */
      public int compare(File file1, File file2) {
          return (getType(file1) - getType(file2));
      }
  
      /**
       * Convert type to numeric value.
       *
       * @param file The file
       * @return 1 for directories and 2 for files
       */
      private int getType(File file) {
          if (file.isDirectory()) {
              return 1;
          } else {
              return 2;
          }
      }
  }
  