/* * Copyright (C) 2007 The Guava Authors * * 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 com.google.common.collect; import static com.google.common.base.Preconditions.checkNotNull; import com.google.common.annotations.GwtCompatible; import java.io.Serializable; import java.util.Iterator; import javax.annotation.Nullable; /** An ordering that uses the reverse of a given order. */ @GwtCompatible(serializable = true) final class ReverseOrdering extends Ordering implements Serializable { final Ordering forwardOrder; ReverseOrdering(Ordering forwardOrder) { this.forwardOrder = checkNotNull(forwardOrder); } @Override public int compare(T a, T b) { return forwardOrder.compare(b, a); } @SuppressWarnings("unchecked") // how to explain? @Override public Ordering reverse() { return (Ordering) forwardOrder; } // Override the min/max methods to "hoist" delegation outside loops @Override public E min(E a, E b) { return forwardOrder.max(a, b); } @Override public E min(E a, E b, E c, E... rest) { return forwardOrder.max(a, b, c, rest); } @Override public E min(Iterator iterator) { return forwardOrder.max(iterator); } @Override public E min(Iterable iterable) { return forwardOrder.max(iterable); } @Override public E max(E a, E b) { return forwardOrder.min(a, b); } @Override public E max(E a, E b, E c, E... rest) { return forwardOrder.min(a, b, c, rest); } @Override public E max(Iterator iterator) { return forwardOrder.min(iterator); } @Override public E max(Iterable iterable) { return forwardOrder.min(iterable); } @Override public int hashCode() { return -forwardOrder.hashCode(); } @Override public boolean equals(@Nullable Object object) { if (object == this) { return true; } if (object instanceof ReverseOrdering) { ReverseOrdering that = (ReverseOrdering) object; return this.forwardOrder.equals(that.forwardOrder); } return false; } @Override public String toString() { return forwardOrder + ".reverse()"; } private static final long serialVersionUID = 0; }