Java tutorial
/* * Copyright (c) 2016 Gridtec. All rights reserved. * * 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 at.gridtec.lambda4j.consumer.bi; import at.gridtec.lambda4j.Lambda; import at.gridtec.lambda4j.consumer.Consumer2; import org.apache.commons.lang3.tuple.Pair; import javax.annotation.Nonnegative; import javax.annotation.Nonnull; import javax.annotation.Nullable; import java.util.Objects; import java.util.function.BiConsumer; import java.util.function.Consumer; import java.util.function.Function; /** * Represents an operation that accepts two input arguments and returns no result. * Unlike most other functional interfaces, {@code BiConsumer2} is expected to operate via side-effects. * <p> * This is a {@link FunctionalInterface} whose functional method is {@link #accept(Object, Object)}. * * @param <T> The type of the first argument to the consumer * @param <U> The type of the second argument to the consumer * @apiNote This is a JDK lambda. * @see BiConsumer2 */ @SuppressWarnings("unused") @FunctionalInterface public interface BiConsumer2<T, U> extends Lambda, BiConsumer<T, U> { /** * Constructs a {@link BiConsumer2} based on a lambda expression or a method reference. Thereby the given lambda * expression or method reference is returned on an as-is basis to implicitly transform it to the desired type. With * this method, it is possible to ensure that correct type is used from lambda expression or method reference. * * @param <T> The type of the first argument to the consumer * @param <U> The type of the second argument to the consumer * @param expression A lambda expression or (typically) a method reference, e.g. {@code this::method} * @return A {@code BiConsumer2} from given lambda expression or method reference. * @implNote This implementation allows the given argument to be {@code null}, but only if {@code null} given, * {@code null} will be returned. * @see <a href="https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html#syntax">Lambda * Expression</a> * @see <a href="https://docs.oracle.com/javase/tutorial/java/javaOO/methodreferences.html">Method Reference</a> */ static <T, U> BiConsumer2<T, U> of(@Nullable final BiConsumer2<T, U> expression) { return expression; } /** * Calls the given {@link BiConsumer} with the given arguments and returns its result. * * @param <T> The type of the first argument to the consumer * @param <U> The type of the second argument to the consumer * @param consumer The consumer to be called * @param t The first argument to the consumer * @param u The second argument to the consumer * @throws NullPointerException If given argument is {@code null} */ static <T, U> void call(@Nonnull final BiConsumer<? super T, ? super U> consumer, T t, U u) { Objects.requireNonNull(consumer); consumer.accept(t, u); } /** * Creates a {@link BiConsumer2} which uses the {@code first} parameter of this one as argument for the given {@link * Consumer}. * * @param <T> The type of the first argument to the consumer * @param <U> The type of the second argument to the consumer * @param consumer The consumer which accepts the {@code first} parameter of this one * @return Creates a {@code BiConsumer2} which uses the {@code first} parameter of this one as argument for the * given {@code Consumer}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull static <T, U> BiConsumer2<T, U> onlyFirst(@Nonnull final Consumer<? super T> consumer) { Objects.requireNonNull(consumer); return (t, u) -> consumer.accept(t); } /** * Creates a {@link BiConsumer2} which uses the {@code second} parameter of this one as argument for the given * {@link Consumer}. * * @param <T> The type of the first argument to the consumer * @param <U> The type of the second argument to the consumer * @param consumer The consumer which accepts the {@code second} parameter of this one * @return Creates a {@code BiConsumer2} which uses the {@code second} parameter of this one as argument for the * given {@code Consumer}. * @throws NullPointerException If given argument is {@code null} */ @Nonnull static <T, U> BiConsumer2<T, U> onlySecond(@Nonnull final Consumer<? super U> consumer) { Objects.requireNonNull(consumer); return (t, u) -> consumer.accept(u); } /** * Applies this consumer to the given arguments. * * @param t The first argument to the consumer * @param u The second argument to the consumer */ void accept(T t, U u); /** * Applies this consumer to the given tuple. * * @param tuple The tuple to be applied to the consumer * @throws NullPointerException If given argument is {@code null} * @see org.apache.commons.lang3.tuple.Pair */ default void accept(@Nonnull Pair<T, U> tuple) { Objects.requireNonNull(tuple); accept(tuple.getLeft(), tuple.getRight()); } /** * Applies this consumer partially to some arguments of this one, producing a {@link Consumer2} as result. * * @param t The first argument to this consumer used to partially apply this function * @return A {@code Consumer2} that represents this consumer partially applied the some arguments. */ @Nonnull default Consumer2<U> paccept(T t) { return (u) -> this.accept(t, u); } /** * Returns the number of arguments for this consumer. * * @return The number of arguments for this consumer. * @implSpec The default implementation always returns {@code 2}. */ @Nonnegative default int arity() { return 2; } /** * Returns a composed {@link BiConsumer2} that first applies the {@code before} functions to its input, and * then applies this consumer to the result. * If evaluation of either operation throws an exception, it is relayed to the caller of the composed operation. * * @param <A> The type of the argument to the first given function, and of composed consumer * @param <B> The type of the argument to the second given function, and of composed consumer * @param before1 The first function to apply before this consumer is applied * @param before2 The second function to apply before this consumer is applied * @return A composed {@code BiConsumer2} that first applies the {@code before} functions to its input, and then * applies this consumer to the result. * @throws NullPointerException If given argument is {@code null} * @implSpec The input argument of this method is able to handle every type. */ @Nonnull default <A, B> BiConsumer2<A, B> compose(@Nonnull final Function<? super A, ? extends T> before1, @Nonnull final Function<? super B, ? extends U> before2) { Objects.requireNonNull(before1); Objects.requireNonNull(before2); return (a, b) -> accept(before1.apply(a), before2.apply(b)); } /** * Returns a composed {@link BiConsumer2} that performs, in sequence, this consumer followed by the {@code after} * consumer. * If evaluation of either operation throws an exception, it is relayed to the caller of the composed operation. * If performing this consumer throws an exception, the {@code after} consumer will not be performed. * * @param after The consumer to apply after this consumer is applied * @return A composed {@link BiConsumer2} that performs, in sequence, this consumer followed by the {@code after} * consumer. * @throws NullPointerException If given argument is {@code null} */ @Nonnull default BiConsumer2<T, U> andThen(@Nonnull final BiConsumer<? super T, ? super U> after) { Objects.requireNonNull(after); return (t, u) -> { accept(t, u); after.accept(t, u); }; } /** * Returns a tupled version of this consumer. * * @return A tupled version of this consumer. */ @Nonnull default Consumer2<Pair<T, U>> tupled() { return this::accept; } /** * Returns a reversed version of this consumer. This may be useful in recursive context. * * @return A reversed version of this consumer. */ @Nonnull default BiConsumer2<U, T> reversed() { return (u, t) -> accept(t, u); } }