/*
* 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 $Revision: 1021884 $ $Date: 2010-10-12 14:49:16 -0400 (Tue, 12 Oct 2010) $
* @since Commons IO 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(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(File file1, 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() + "]";
}
}
|