1 /* 2 * Copyright (C) 2007 Google Inc. 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 com.google.common.annotations.GwtCompatible; 20 import static com.google.common.base.Preconditions.checkNotNull; 21 22 import java.io.Serializable; 23 import java.util.Collections; 24 import java.util.Comparator; 25 import java.util.List; 26 27 import javax.annotation.Nullable; 28 29 /** An ordering for a pre-existing {@code comparator}. */ 30 @GwtCompatible(serializable = true) 31 final class ComparatorOrdering<T> extends Ordering<T> implements Serializable { 32 final Comparator<T> comparator; 33 34 ComparatorOrdering(Comparator<T> comparator) { 35 this.comparator = checkNotNull(comparator); 36 } 37 38 public int compare(T a, T b) { 39 return comparator.compare(a, b); 40 } 41 42 // Override just to remove a level of indirection from inner loops 43 @Override public int binarySearch(List<? extends T> sortedList, T key) { 44 return Collections.binarySearch(sortedList, key, comparator); 45 } 46 47 // Override just to remove a level of indirection from inner loops 48 @Override public <E extends T> List<E> sortedCopy(Iterable<E> iterable) { 49 List<E> list = Lists.newArrayList(iterable); 50 Collections.sort(list, comparator); 51 return list; 52 } 53 54 @Override public boolean equals(@Nullable Object object) { 55 if (object == this) { 56 return true; 57 } 58 if (object instanceof ComparatorOrdering) { 59 ComparatorOrdering<?> that = (ComparatorOrdering<?>) object; 60 return this.comparator.equals(that.comparator); 61 } 62 return false; 63 } 64 65 @Override public int hashCode() { 66 return comparator.hashCode(); 67 } 68 69 @Override public String toString() { 70 return comparator.toString(); 71 } 72 73 private static final long serialVersionUID = 0; 74 } 75
