/** * 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); } }