/**
* Copyright 2008 Google Inc.
*
* Licensed 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.waveprotocol.wave.client.common.util;
import java.util.Comparator;
/**
* Used to chain comparators. First compare the arguments using the first
* comparator. If non-zero, return the result. Return the results of the second
* comparator.
*
* This can be nested to combine arbitrary number of comparators.
*
*
* @param <T>
*/
public final class ChainComparator<T> implements Comparator<T> {
private final Comparator<? super T> firstComparator;
private final Comparator<? super T> secondComparator;
public ChainComparator(Comparator<? super T> firstComparator,
Comparator<? super T> secondComparator) {
this.firstComparator = firstComparator;
this.secondComparator = secondComparator;
}
/** {@inheritDoc} **/
public int compare(T o1, T o2) {
int cmp = firstComparator.compare(o1, o2);
return cmp != 0 ? cmp : secondComparator.compare(o1, o2);
}
}