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 com.google.common.annotations.GwtCompatible; 20 21 import java.io.Serializable; 22 import java.util.Comparator; 23 import java.util.List; 24 25 /** An ordering that tries several comparators in order. */ 26 @GwtCompatible(serializable = true) 27 final class CompoundOrdering<T> extends Ordering<T> implements Serializable { 28 final ImmutableList<Comparator<? super T>> comparators; 29 CompoundOrdering(Comparator<? super T> primary, Comparator<? super T> secondary)30 CompoundOrdering(Comparator<? super T> primary, 31 Comparator<? super T> secondary) { 32 this.comparators 33 = ImmutableList.<Comparator<? super T>>of(primary, secondary); 34 } 35 CompoundOrdering(Iterable<? extends Comparator<? super T>> comparators)36 CompoundOrdering(Iterable<? extends Comparator<? super T>> comparators) { 37 this.comparators = ImmutableList.copyOf(comparators); 38 } 39 CompoundOrdering(List<? extends Comparator<? super T>> comparators, Comparator<? super T> lastComparator)40 CompoundOrdering(List<? extends Comparator<? super T>> comparators, 41 Comparator<? super T> lastComparator) { 42 this.comparators = new ImmutableList.Builder<Comparator<? super T>>() 43 .addAll(comparators).add(lastComparator).build(); 44 } 45 compare(T left, T right)46 @Override public int compare(T left, T right) { 47 for (Comparator<? super T> comparator : comparators) { 48 int result = comparator.compare(left, right); 49 if (result != 0) { 50 return result; 51 } 52 } 53 return 0; 54 } 55 equals(Object object)56 @Override public boolean equals(Object object) { 57 if (object == this) { 58 return true; 59 } 60 if (object instanceof CompoundOrdering) { 61 CompoundOrdering<?> that = (CompoundOrdering<?>) object; 62 return this.comparators.equals(that.comparators); 63 } 64 return false; 65 } 66 hashCode()67 @Override public int hashCode() { 68 return comparators.hashCode(); 69 } 70 toString()71 @Override public String toString() { 72 return "Ordering.compound(" + comparators + ")"; 73 } 74 75 private static final long serialVersionUID = 0; 76 } 77