1 /* 2 * Copyright (C) 2012 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 com.google.common.annotations.GwtCompatible; 20 21 import java.io.Serializable; 22 import java.util.List; 23 24 import javax.annotation.Nullable; 25 26 /** 27 * An ordering that treats all references as equals, even nulls. 28 * 29 * @author Emily Soldal 30 */ 31 @GwtCompatible(serializable = true) 32 final class AllEqualOrdering extends Ordering<Object> implements Serializable { 33 static final AllEqualOrdering INSTANCE = new AllEqualOrdering(); 34 35 @Override 36 public int compare(@Nullable Object left, @Nullable Object right) { 37 return 0; 38 } 39 40 @Override 41 public <E> List<E> sortedCopy(Iterable<E> iterable) { 42 return Lists.newArrayList(iterable); 43 } 44 45 @Override 46 public <E> ImmutableList<E> immutableSortedCopy(Iterable<E> iterable) { 47 return ImmutableList.copyOf(iterable); 48 } 49 50 @SuppressWarnings("unchecked") 51 @Override 52 public <S> Ordering<S> reverse() { 53 return (Ordering<S>) this; 54 } 55 56 private Object readResolve() { 57 return INSTANCE; 58 } 59 60 @Override 61 public String toString() { 62 return "Ordering.allEqual()"; 63 } 64 65 private static final long serialVersionUID = 0; 66 } 67
