1 /* 2 * Copyright (C) 2007 The Guava Authors 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 package com.google.common.collect; 18 19 import static com.google.common.base.Preconditions.checkNotNull; 20 21 import com.google.common.annotations.GwtCompatible; 22 23 import java.io.Serializable; 24 import java.util.Comparator; 25 26 import javax.annotation.Nullable; 27 28 /** An ordering for a pre-existing comparator. */ 29 @GwtCompatible(serializable = true) 30 final class ComparatorOrdering<T> extends Ordering<T> implements Serializable { 31 final Comparator<T> comparator; 32 33 ComparatorOrdering(Comparator<T> comparator) { 34 this.comparator = checkNotNull(comparator); 35 } 36 37 @Override public int compare(T a, T b) { 38 return comparator.compare(a, b); 39 } 40 41 @Override public boolean equals(@Nullable Object object) { 42 if (object == this) { 43 return true; 44 } 45 if (object instanceof ComparatorOrdering) { 46 ComparatorOrdering<?> that = (ComparatorOrdering<?>) object; 47 return this.comparator.equals(that.comparator); 48 } 49 return false; 50 } 51 52 @Override public int hashCode() { 53 return comparator.hashCode(); 54 } 55 56 @Override public String toString() { 57 return comparator.toString(); 58 } 59 60 private static final long serialVersionUID = 0; 61 } 62
