/*

  * 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;

 /**

  * Reverses the result of comparing two objects using

  * the delegate {@link Comparator}.

  *

  * @version $Id: ReverseComparator.java 1415850 2012-11-30 20:51:39Z ggregory $

  * @since 1.4

  */

 class ReverseComparator extends AbstractFileComparator implements Serializable {

     private final Comparator<File> delegate;

     /**

      * Construct an instance with the sepecified delegate {@link Comparator}.

      *

      * @param delegate The comparator to delegate to

      */

     public ReverseComparator(final Comparator<File> delegate) {

         if (delegate == null) {

             throw new IllegalArgumentException("Delegate comparator is missing");

         }

         this.delegate = delegate;

     }

     /**

      * Compare using the delegate Comparator, but reversing the result.

      * 

      * @param file1 The first file to compare

      * @param file2 The second file to compare

      * @return the result from the delegate {@link Comparator#compare(Object, Object)}

      * reversing the value (i.e. positive becomes negative and vice versa)

      */

     public int compare(final File file1, final File file2) {

         return delegate.compare(file2, file1); // parameters switched round

     }

     /**

      * String representation of this file comparator.

      *

      * @return String representation of this file comparator

      */

     @Override

     public String toString() {

         return super.toString() + "[" + delegate.toString() + "]";

     }

 }