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.Collections; 25 import java.util.Comparator; 26 import java.util.List; 27 28 import javax.annotation.Nullable; 29 30 /** An ordering for a pre-existing comparator. */ 31 @GwtCompatible(serializable = true) 32 final class ComparatorOrdering<T> extends Ordering<T> implements Serializable { 33 final Comparator<T> comparator; 34 ComparatorOrdering(Comparator<T> comparator)35 ComparatorOrdering(Comparator<T> comparator) { 36 this.comparator = checkNotNull(comparator); 37 } 38 compare(T a, T b)39 @Override public int compare(T a, T b) { 40 return comparator.compare(a, b); 41 } 42 43 // Override just to remove a level of indirection from inner loops binarySearch(List<? extends T> sortedList, T key)44 @Override public int binarySearch(List<? extends T> sortedList, T key) { 45 return Collections.binarySearch(sortedList, key, comparator); 46 } 47 48 // Override just to remove a level of indirection from inner loops sortedCopy(Iterable<E> iterable)49 @Override public <E extends T> List<E> sortedCopy(Iterable<E> iterable) { 50 List<E> list = Lists.newArrayList(iterable); 51 Collections.sort(list, comparator); 52 return list; 53 } 54 equals(@ullable Object object)55 @Override public boolean equals(@Nullable Object object) { 56 if (object == this) { 57 return true; 58 } 59 if (object instanceof ComparatorOrdering) { 60 ComparatorOrdering<?> that = (ComparatorOrdering<?>) object; 61 return this.comparator.equals(that.comparator); 62 } 63 return false; 64 } 65 hashCode()66 @Override public int hashCode() { 67 return comparator.hashCode(); 68 } 69 toString()70 @Override public String toString() { 71 return comparator.toString(); 72 } 73 74 private static final long serialVersionUID = 0; 75 } 76