| /* |
| * Copyright 2016 Google Inc. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); you may not |
| * use this file except in compliance with the License. You may obtain a copy of |
| * the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT |
| * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the |
| * License for the specific language governing permissions and limitations under |
| * the License. |
| */ |
| package java.util.stream; |
| |
| import static javaemul.internal.InternalPreconditions.checkNotNull; |
| |
| import java.util.Set; |
| import java.util.function.BiConsumer; |
| import java.util.function.BinaryOperator; |
| import java.util.function.Function; |
| import java.util.function.Supplier; |
| |
| /** |
| * See <a |
| * href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Collector.html">the |
| * official Java API doc</a> for details. |
| * @param <T> the type of data to be collected |
| * @param <A> the type of accumulator used to track results |
| * @param <R> the final output data type |
| */ |
| public interface Collector<T,A,R> { |
| |
| /** |
| * See <a |
| * href="https://docs.oracle.com/javase/8/docs/api/java/util/stream/Collector.Characteristics.html"> |
| * the official Java API doc</a> for details. |
| */ |
| enum Characteristics { CONCURRENT, IDENTITY_FINISH, UNORDERED } |
| |
| static <T, A, R> Collector<T, A, R> of( |
| Supplier<A> supplier, |
| BiConsumer<A, T> accumulator, |
| BinaryOperator<A> combiner, |
| Function<A, R> finisher, |
| Characteristics... characteristics) { |
| checkNotNull(supplier); |
| checkNotNull(accumulator); |
| checkNotNull(combiner); |
| checkNotNull(finisher); |
| checkNotNull(characteristics); |
| return new CollectorImpl<>(supplier, accumulator, combiner, finisher, characteristics); |
| } |
| |
| static <T, R> Collector<T, R, R> of( |
| Supplier<R> supplier, |
| BiConsumer<R, T> accumulator, |
| BinaryOperator<R> combiner, |
| Characteristics... characteristics) { |
| checkNotNull(supplier); |
| checkNotNull(accumulator); |
| checkNotNull(combiner); |
| checkNotNull(characteristics); |
| return new CollectorImpl<T, R, R>( |
| supplier, accumulator, combiner, Function.identity(), characteristics); |
| } |
| |
| Supplier<A> supplier(); |
| |
| BiConsumer<A,T> accumulator(); |
| |
| Set<Characteristics> characteristics(); |
| |
| BinaryOperator<A> combiner(); |
| |
| Function<A,R> finisher(); |
| } |