CheckedBiFunction.java

/*-
 * #%L
 * io.earcam.unexceptional
 * %%
 * Copyright (C) 2016 - 2017 earcam
 * %%
 * SPDX-License-Identifier: (BSD-3-Clause OR EPL-1.0 OR Apache-2.0 OR MIT)
 * 
 * You <b>must</b> choose to accept, in full - any individual or combination of 
 * the following licenses:
 * <ul>
 * 	<li><a href="https://opensource.org/licenses/BSD-3-Clause">BSD-3-Clause</a></li>
 * 	<li><a href="https://www.eclipse.org/legal/epl-v10.html">EPL-1.0</a></li>
 * 	<li><a href="https://www.apache.org/licenses/LICENSE-2.0">Apache-2.0</a></li>
 * 	<li><a href="https://opensource.org/licenses/MIT">MIT</a></li>
 * </ul>
 * #L%
 */
package io.earcam.unexceptional;

import java.util.Objects;

/**
 * A checked parallel of {@link java.util.function.BiFunction}
 * 
 * @param <T> first argument type
 * @param <U> second argument type
 * @param <R> return type
 * 
 * @since 0.2.0
 * 
 * @see java.util.function.BiFunction
 */
@FunctionalInterface
public interface CheckedBiFunction<T, U, R, E extends Throwable> {

	/**
	 * See {@link java.util.function.BiFunction#apply(Object, Object)}
	 * 
	 * @param t first argument.
	 * @param u second argument.
	 * @return result of applying {@code this} function.
	 * @throws Throwable a possible checked exception
	 */
	public abstract R apply(T t, U u) throws E;


	/**
	 * See {@link java.util.function.BiFunction#andThen(java.util.function.Function)}
	 * 
	 * @param <V> the return type of the {@code after} parameter
	 * 
	 * @param after the {@link CheckedFunction} to be chained (taking result of {@code this} as argument)
	 * @return the composite {@link CheckedBiFunction}
	 * @throws NullPointerException if {@code after} is {@code null}
	 */
	public default <V> CheckedBiFunction<T, U, V, E> andThen(CheckedFunction<? super R, ? extends V, ? extends E> after)
	{
		Objects.requireNonNull(after);
		return (CheckedBiFunction<T, U, V, E> & java.io.Serializable) (T t, U u) -> after.apply(apply(t, u));
	}
}