BiFunctionWithException.java
/**
* Powerunit - A JDK1.8 test framework
* Copyright (C) 2014 Mathieu Boretti.
*
* This file is part of Powerunit
*
* Powerunit is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Powerunit is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Powerunit. If not, see <http://www.gnu.org/licenses/>.
*/
package ch.powerunit.extensions.exceptions;
import static ch.powerunit.extensions.exceptions.Constants.verifyExceptionMapper;
import static ch.powerunit.extensions.exceptions.Constants.verifyFunction;
import static java.util.Objects.requireNonNull;
import java.util.Optional;
import java.util.concurrent.CompletionStage;
import java.util.function.BiFunction;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* Represents a function that accepts two arguments, may thrown exception and
* produces a result. This is the two-arity specialization of
* {@link FunctionWithException}.
*
* <h3>General contract</h3>
* <ul>
* <li><b>{@link #apply(Object, Object) R apply(T t, U u) throws
* E}</b> - The functional method.</li>
* <li><b>uncheck</b> - Return a {@code BiFunction<T,U,R>}</li>
* <li><b>lift</b> - Return a
* {@code BiFunction<T,U,<Optional<R>>}</li>
* <li><b>ignore</b> - Return a {@code BiFunction<T,U,R>}</li>
* </ul>
*
* @see BiFunction
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception of the function
*/
@FunctionalInterface
public interface BiFunctionWithException<T, U, R, E extends Exception> extends
ObjectReturnExceptionHandlerSupport<BiFunction<T, U, R>, BiFunction<T, U, Optional<R>>, BiFunction<T, U, CompletionStage<R>>, R, BiFunctionWithException<T, U, R, E>> {
/**
* Applies this function to the given arguments.
*
* @param t
* the first function argument
* @param u
* the second function argument
* @return the function result
* @throws E
* any exception
* @see BiFunction#apply(Object,Object)
*/
R apply(T t, U u) throws E;
/**
* Converts this {@code BiFunctionWithException} to a {@code BiFunction} that
* wraps exception to {@code RuntimeException}.
*
* @return the unchecked function
* @see #unchecked(BiFunctionWithException)
* @see #unchecked(BiFunctionWithException, Function)
* @see BiFunction
*/
@Override
default BiFunction<T, U, R> uncheck() {
return (t, u) -> ObjectReturnExceptionHandlerSupport.unchecked(() -> apply(t, u), throwingHandler());
}
/**
* Converts this {@code BiFunctionWithException} to a lifted {@code BiFunction}
* using {@code Optional} as return value.
*
* @return the lifted function
* @see #lifted(BiFunctionWithException)
* @see BiFunction
*/
@Override
default BiFunction<T, U, Optional<R>> lift() {
return (t, u) -> ObjectReturnExceptionHandlerSupport.unchecked(() -> Optional.ofNullable(apply(t, u)),
notThrowingHandler());
}
/**
* Converts this {@code BiFunctionWithException} to a lifted {@code BiFunction}
* returning {@code null} (or the value redefined by the method
* {@link #defaultValue()}) in case of exception.
*
* @return the function that ignore error
* @see #ignored(BiFunctionWithException)
* @see BiFunction
*/
@Override
default BiFunction<T, U, R> ignore() {
return lift().andThen(o -> o.orElse(defaultValue()));
}
/**
* Convert this {@code BiFunctionWithException} to a lifted {@code BiFunction}
* that uses {@code CompletionStage} as return value.
*
* @return the lifted function
* @see #staged(BiFunctionWithException)
* @see BiFunction
* @see CompletionStage
*/
@Override
default BiFunction<T, U, CompletionStage<R>> stage() {
return (t, u) -> ObjectReturnExceptionHandlerSupport.staged(() -> apply(t, u));
}
/**
* Returns a composed {@code FunctionWithException} that first applies this
* {@code FunctionWithException} to its input, and then applies the
* {@code after} {@code FunctionWithException} to the result. If evaluation of
* either {@code FunctionWithException} throws an exception, it is relayed to
* the caller of the composed function.
*
* @param <V>
* the type of output of the {@code after}
* {@code FunctionWithException}, and of the composed
* {@code FunctionWithException}
* @param after
* the function to apply after this {@code FunctionWithException} is
* applied
* @return a composed function that first applies this function and then applies
* the {@code after} function
* @throws NullPointerException
* if after is null
*
* @see BiFunction#andThen(Function)
*/
default <V> BiFunctionWithException<T, U, V, E> andThen(
FunctionWithException<? super R, ? extends V, ? extends E> after) {
requireNonNull(after);
return (T t, U u) -> after.apply(apply(t, u));
}
/**
* Returns a {@code FunctionWithException} that always throw exception.
*
* @param exceptionBuilder
* the supplier to create the exception
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the exception
* @return a function that always throw exception
*/
static <T, U, R, E extends Exception> BiFunctionWithException<T, U, R, E> failing(Supplier<E> exceptionBuilder) {
return (t, u) -> {
throw exceptionBuilder.get();
};
}
/**
* Converts a {@code BiFunctionWithException} to a {@code BiFunction} that
* convert exception to {@code RuntimeException}.
* <p>
* For example :
*
* <pre>
* BiFunction<String, String, String> biFunctionThrowingRuntimeException = BiFunctionWithException
* .unchecked(biFouctionThrowingException);
* </pre>
*
* Will generate a {@code BiFunction} throwing {@code RuntimeException} in case
* of error.
*
* @param function
* to be unchecked
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the unchecked exception
* @see #uncheck()
* @see #unchecked(BiFunctionWithException, Function)
* @throws NullPointerException
* if function is null
*/
static <T, U, R, E extends Exception> BiFunction<T, U, R> unchecked(BiFunctionWithException<T, U, R, E> function) {
return verifyFunction(function).uncheck();
}
/**
* Converts a {@code BiFunctionWithException} to a {@code BiFunction} that
* convert exception to {@code RuntimeException} by using the provided mapping
* function.
* <p>
* For example :
*
* <pre>
* BiFunction<String, String, String> functionThrowingRuntimeException = BiFunctionWithException
* .unchecked(fonctionThrowingException, IllegalArgumentException::new);
* </pre>
*
* Will generate a {@code BiFunction} throwing {@code IllegalArgumentException}
* in case of error.
*
* @param function
* the be unchecked
* @param exceptionMapper
* a function to convert the exception to the runtime exception.
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the unchecked exception
* @see #uncheck()
* @see #unchecked(BiFunctionWithException)
* @throws NullPointerException
* if function or exceptionMapper is null
*/
static <T, U, R, E extends Exception> BiFunction<T, U, R> unchecked(BiFunctionWithException<T, U, R, E> function,
Function<Exception, RuntimeException> exceptionMapper) {
verifyFunction(function);
verifyExceptionMapper(exceptionMapper);
return new BiFunctionWithException<T, U, R, E>() {
@Override
public R apply(T t, U u) throws E {
return function.apply(t, u);
}
@Override
public Function<Exception, RuntimeException> exceptionMapper() {
return exceptionMapper;
}
}.uncheck();
}
/**
* Converts a {@code BiFunctionWithException} to a lifted {@code BiFunction}
* using {@code Optional} as return value.
*
* @param function
* to be lifted
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #lift()
* @throws NullPointerException
* if function is null
*/
static <T, U, R, E extends Exception> BiFunction<T, U, Optional<R>> lifted(
BiFunctionWithException<T, U, R, E> function) {
return verifyFunction(function).lift();
}
/**
* Converts a {@code BiFunctionWithException} to a lifted {@code BiFunction}
* returning {@code null} in case of exception.
*
* @param function
* to be lifted
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @throws NullPointerException
* if function is null
*/
static <T, U, R, E extends Exception> BiFunction<T, U, R> ignored(BiFunctionWithException<T, U, R, E> function) {
return verifyFunction(function).ignore();
}
/**
* Converts a {@code BiFunctionWithException} to a lifted {@code BiFunction}
* returning a default in case of exception.
*
* @param function
* to be lifted
* @param defaultValue
* the value to be returned in case of error
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @see #ignored(BiFunctionWithException)
* @throws NullPointerException
* if function is null
* @since 3.0.0
*/
static <T, U, R, E extends Exception> BiFunction<T, U, R> ignored(BiFunctionWithException<T, U, R, E> function,
R defaultValue) {
verifyFunction(function);
return new BiFunctionWithException<T, U, R, E>() {
@Override
public R apply(T t, U u) throws E {
return function.apply(t, u);
}
@Override
public R defaultValue() {
return defaultValue;
}
}.ignore();
}
/**
* Convert this {@code BiFunctionWithException} to a lifted {@code BiFunction}
* return {@code CompletionStage} as return value.
*
* @param function
* to be lifted
* @param <T>
* the type of the first argument to the function
* @param <U>
* the type of the second argument to the function
* @param <R>
* the type of the result of the function
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #stage()
* @throws NullPointerException
* if function is null
*/
static <T, U, R, E extends Exception> BiFunction<T, U, CompletionStage<R>> staged(
BiFunctionWithException<T, U, R, E> function) {
return verifyFunction(function).stage();
}
/**
* Converts a {@code BiFunctionWithException} to a
* {@code BiConsumerWithException}.
*
* @param function
* to be converter
* @param <T>
* the type of the first argument to the operation
* @param <U>
* the type of the second argument to the operation
* @param <R>
* the type of the return value of the function
* @param <E>
* the type of the potential exception of the operation
* @return the consumer
* @throws NullPointerException
* if function is null
* @since 1.2.0
*/
static <T, U, R, E extends Exception> BiConsumerWithException<T, U, E> asBiConsumer(
BiFunctionWithException<T, U, R, E> function) {
return verifyFunction(function).asBiConsumer();
}
/**
* Converts a {@code BiFunctionWithException} to a
* {@code BiConsumerWithException}.
*
* @return the consumer
* @since 1.2.0
*/
default BiConsumerWithException<T, U, E> asBiConsumer() {
return this::apply;
}
/**
* Converts a {@code BiFunctionWithException} to a
* {@code FunctionWithException}.
*
* @param function
* to be converter
*
* @param u
* the second parameter of the {@code BiFunctionWithException} that
* will be used inside the new {code FunctionWithException}.
* @param <T>
* the type of the first argument to the operation
* @param <U>
* the type of the second argument to the operation
* @param <R>
* the type of the return value of the function
* @param <E>
* the type of the potential exception of the operation
* @return the consumer
* @throws NullPointerException
* if function is null
* @since 1.2.0
*/
static <T, U, R, E extends Exception> FunctionWithException<T, R, E> asFunction(
BiFunctionWithException<T, U, R, E> function, U u) {
return verifyFunction(function).asFunction(u);
}
/**
* Converts a {@code BiFunctionWithException} to a
* {@code FunctionWithException}.
*
* @param u
* the second parameter of the {@code BiFunctionWithException} that
* will be used inside the new {code FunctionWithException}.
*
*
* @return the consumer
* @since 1.2.0
*/
default FunctionWithException<T, R, E> asFunction(U u) {
return t -> apply(t, u);
}
}