1090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson/* 21d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert * Copyright (C) 2007 The Guava Authors 3090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 4090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * Licensed under the Apache License, Version 2.0 (the "License"); 5090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * you may not use this file except in compliance with the License. 6090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * You may obtain a copy of the License at 7090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 8090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * http://www.apache.org/licenses/LICENSE-2.0 9090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * 10090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * Unless required by applicable law or agreed to in writing, software 11090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * distributed under the License is distributed on an "AS IS" BASIS, 12090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * See the License for the specific language governing permissions and 14090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * limitations under the License. 15090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson */ 16090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 17090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonpackage com.google.common.collect; 18090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 19090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport com.google.common.annotations.GwtCompatible; 20090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 21090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport java.io.Serializable; 22090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport java.util.List; 23090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 24090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport javax.annotation.Nullable; 25090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 26090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson/** An ordering that compares objects according to a given order. */ 27090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson@GwtCompatible(serializable = true) 28090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonfinal class ExplicitOrdering<T> extends Ordering<T> implements Serializable { 29090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson final ImmutableMap<T, Integer> rankMap; 30090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 31090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ExplicitOrdering(List<T> valuesInOrder) { 32090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson this(buildRankMap(valuesInOrder)); 33090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 34090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 35090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ExplicitOrdering(ImmutableMap<T, Integer> rankMap) { 36090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson this.rankMap = rankMap; 37090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 38090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 391d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public int compare(T left, T right) { 40090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return rank(left) - rank(right); // safe because both are nonnegative 41090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 42090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 43090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson private int rank(T value) { 44090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson Integer rank = rankMap.get(value); 45090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (rank == null) { 46090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson throw new IncomparableValueException(value); 47090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 48090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return rank; 49090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 50090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 51090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson private static <T> ImmutableMap<T, Integer> buildRankMap( 52090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson List<T> valuesInOrder) { 53090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ImmutableMap.Builder<T, Integer> builder = ImmutableMap.builder(); 54090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson int rank = 0; 55090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson for (T value : valuesInOrder) { 56090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson builder.put(value, rank++); 57090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 58090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return builder.build(); 59090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 60090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 61090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public boolean equals(@Nullable Object object) { 62090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (object instanceof ExplicitOrdering) { 63090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ExplicitOrdering<?> that = (ExplicitOrdering<?>) object; 64090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return this.rankMap.equals(that.rankMap); 65090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 66090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return false; 67090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 68090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 69090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public int hashCode() { 70090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return rankMap.hashCode(); 71090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 72090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 73090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public String toString() { 74090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return "Ordering.explicit(" + rankMap.keySet() + ")"; 75090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 76090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 77090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson private static final long serialVersionUID = 0; 78090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson} 79