BinaryOperatorWithException.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 java.util.Optional;
import java.util.function.BiFunction;
import java.util.function.BinaryOperator;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* Represents an operation upon two operands of the same type, that may throw
* exception, producing a result of the same type as the operands. This is a
* specialization of {@link BiFunctionWithException} for the case where the
* operands and the result are all of the same type.
* <p>
* As this interface must return the same type of the input, a lifted version
* which returns {@code Optional} is not possible.
* <h3>General contract</h3>
* <ul>
* <li><b>{@link #apply(Object, Object) T apply(T t, T u) throws
* E}</b> - The functional method.</li>
* <li><b>uncheck</b> - Return a {@code BinaryOperator<T>}</li>
* <li><b>lift</b> - Return a
* {@code BiFunction<T,T,<Optional<T>>}</li>
* <li><b>ignore</b> - Return a {@code BinaryOperator<T>}</li>
* </ul>
*
* @see BiFunctionWithException
* @see BinaryOperator
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the potential exception of the function
*/
@FunctionalInterface
public interface BinaryOperatorWithException<T, E extends Exception> extends BiFunctionWithException<T, T, T, E> {
/**
* Converts this {@code BinaryOperatorWithException} to a {@code BinaryOperator}
* that convert exception to {@code RuntimeException}.
*
* @return the unchecked function
* @see #unchecked(BinaryOperatorWithException)
* @see #unchecked(BinaryOperatorWithException, Function)
*/
@Override
default BinaryOperator<T> uncheck() {
return (t, u) -> ObjectReturnExceptionHandlerSupport.unchecked(() -> apply(t, u), throwingHandler());
}
/**
* Converts this {@code BinaryOperatorWithException} to a lifted
* {@code BinaryOperator} returning {@code null} in case of exception.
*
* @return the function that ignore error
* @see #ignored(BinaryOperatorWithException)
*/
@Override
default BinaryOperator<T> ignore() {
return (t, u) -> ObjectReturnExceptionHandlerSupport.unchecked(() -> apply(t, u), e -> null);
}
@Override
default BinaryOperatorWithException<T, E> documented(Supplier<String> toString) {
return (BinaryOperatorWithException<T, E>) BiFunctionWithException.super.documented(toString);
}
/**
* Returns a binary operator that always throw exception.
*
* @param exceptionBuilder
* the supplier to create the exception
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the exception
* @return a function that always throw exception
*/
static <T, E extends Exception> BinaryOperatorWithException<T, E> failing(Supplier<E> exceptionBuilder) {
return (t, u) -> {
throw exceptionBuilder.get();
};
}
/**
* Converts a {@code BinaryOperatorWithException} to a {@code BinaryOperator}
* that convert exception to {@code RuntimeException}.
*
* @param function
* to be unchecked
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the potential exception
* @return the unchecked exception
* @see #uncheck()
* @see #unchecked(BinaryOperatorWithException, Function)
* @throws NullPointerException
* if function is null
*/
static <T, E extends Exception> BinaryOperator<T> unchecked(BinaryOperatorWithException<T, E> function) {
return verifyFunction(function).uncheck();
}
/**
* Converts a {@code BinaryOperatorWithException} to a {@code BinaryOperator}
* that convert exception to {@code RuntimeException} by using the provided
* mapping function.
*
* @param function
* the be unchecked
* @param exceptionMapper
* a function to convert the exception to the runtime exception.
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the potential exception
* @return the unchecked exception
* @see #uncheck()
* @see #unchecked(BinaryOperatorWithException)
* @throws NullPointerException
* if function or exceptionMapper is null
*/
static <T, E extends Exception> BinaryOperator<T> unchecked(BinaryOperatorWithException<T, E> function,
Function<Exception, RuntimeException> exceptionMapper) {
verifyFunction(function);
verifyExceptionMapper(exceptionMapper);
return new BinaryOperatorWithException<T, E>() {
@Override
public T apply(T t, T u) throws E {
return function.apply(t, u);
}
@Override
public Function<Exception, RuntimeException> exceptionMapper() {
return exceptionMapper;
}
}.uncheck();
}
/**
* Converts a {@code BinaryOperatorWithException} to a lifted {@code Function}
* returning an optional in case of exception.
*
* @param function
* the be unchecked
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @throws NullPointerException
* if function is null
*/
static <T, E extends Exception> BiFunction<T, T, Optional<T>> lifted(BinaryOperatorWithException<T, E> function) {
return verifyFunction(function).lift();
}
/**
* Converts a {@code BinaryOperatorWithException} to a lifted
* {@code BinaryOperator} returning {@code null} in case of exception.
*
* @param function
* the be unchecked
* @param <T>
* the type of the operands and result of the operator
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @throws NullPointerException
* if function is null
*/
static <T, E extends Exception> BinaryOperator<T> ignored(BinaryOperatorWithException<T, E> function) {
return verifyFunction(function).ignore();
}
}