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 191d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringertimport static com.google.common.base.Preconditions.checkNotNull; 201d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert 21090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport com.google.common.annotations.GwtCompatible; 22090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport com.google.common.base.Function; 23090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport com.google.common.base.Objects; 24090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 25090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport java.io.Serializable; 26090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 27090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonimport javax.annotation.Nullable; 28090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 29090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson/** 30090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * An ordering that orders elements by applying an order to the result of a 31090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson * function on those elements. 32090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson */ 33090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson@GwtCompatible(serializable = true) 34090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilsonfinal class ByFunctionOrdering<F, T> 35090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson extends Ordering<F> implements Serializable { 36090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson final Function<F, ? extends T> function; 37090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson final Ordering<T> ordering; 38090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 39090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ByFunctionOrdering( 40090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson Function<F, ? extends T> function, Ordering<T> ordering) { 41090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson this.function = checkNotNull(function); 42090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson this.ordering = checkNotNull(ordering); 43090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 44090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 451d580d0f6ee4f21eb309ba7b509d2c6d671c4044Bjorn Bringert @Override public int compare(F left, F right) { 46090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return ordering.compare(function.apply(left), function.apply(right)); 47090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 48090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 49090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public boolean equals(@Nullable Object object) { 50090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (object == this) { 51090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return true; 52090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 53090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson if (object instanceof ByFunctionOrdering) { 54090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson ByFunctionOrdering<?, ?> that = (ByFunctionOrdering<?, ?>) object; 55090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return this.function.equals(that.function) 56090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson && this.ordering.equals(that.ordering); 57090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 58090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return false; 59090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 60090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 61090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public int hashCode() { 62090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return Objects.hashCode(function, ordering); 63090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 64090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 65090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson @Override public String toString() { 66090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson return ordering + ".onResultOf(" + function + ")"; 67090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson } 68090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson 69090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson private static final long serialVersionUID = 0; 70090f9b4c879985bc747c214f82c62471e60c7742Jesse Wilson} 71