1090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2007 The Guava Authors 3090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 4090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * Licensed under the Apache License, Version 2.0 (the "License"); 5090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * you may not use this file except in compliance with the License. 6090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * You may obtain a copy of the License at 7090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 8090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 9090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 10090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * Unless required by applicable law or agreed to in writing, software 11090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 12090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * See the License for the specific language governing permissions and 14090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * limitations under the License. 15090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson */ 16090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 17090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonpackage com.google.common.collect; 18090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 19090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport static com.google.common.base.Preconditions.checkNotNull; 20090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 211d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport com.google.common.annotations.GwtCompatible; 221d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 23090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport java.io.Serializable; 241d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport java.util.Iterator; 25090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 26090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport javax.annotation.Nullable; 27090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 28090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson/** An ordering that uses the reverse of a given order. */ 29090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson@GwtCompatible(serializable = true) 30090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonfinal class ReverseOrdering<T> extends Ordering<T> implements Serializable { 31090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson final Ordering<? super T> forwardOrder; 32090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 33090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ReverseOrdering(Ordering<? super T> forwardOrder) { 34090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson this.forwardOrder = checkNotNull(forwardOrder); 35090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 36090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 371d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public int compare(T a, T b) { 38090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.compare(b, a); 39090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 40090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 41090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @SuppressWarnings("unchecked") // how to explain? 42090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <S extends T> Ordering<S> reverse() { 431d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return (Ordering<S>) forwardOrder; 44090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 45090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 461d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert // Override the min/max methods to "hoist" delegation outside loops 47090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 48090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E min(E a, E b) { 49090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.max(a, b); 50090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 51090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 52090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E min(E a, E b, E c, E... rest) { 53090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.max(a, b, c, rest); 54090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 55090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 561d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public <E extends T> E min(Iterator<E> iterator) { 571d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return forwardOrder.max(iterator); 581d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 591d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 60090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E min(Iterable<E> iterable) { 61090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.max(iterable); 62090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 63090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 64090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E max(E a, E b) { 65090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.min(a, b); 66090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 67090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 68090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E max(E a, E b, E c, E... rest) { 69090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.min(a, b, c, rest); 70090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 71090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 721d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public <E extends T> E max(Iterator<E> iterator) { 731d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert return forwardOrder.min(iterator); 741d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert } 751d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 76090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public <E extends T> E max(Iterable<E> iterable) { 77090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder.min(iterable); 78090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 79090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 80090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public int hashCode() { 81090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return -forwardOrder.hashCode(); 82090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 83090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 84090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public boolean equals(@Nullable Object object) { 85090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (object == this) { 86090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return true; 87090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 88090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (object instanceof ReverseOrdering) { 89090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ReverseOrdering<?> that = (ReverseOrdering<?>) object; 90090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return this.forwardOrder.equals(that.forwardOrder); 91090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 92090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return false; 93090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 94090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 95090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public String toString() { 96090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return forwardOrder + ".reverse()"; 97090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 98090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 99090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson private static final long serialVersionUID = 0; 100090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson} 101