DoubleUnaryOperatorWithException.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.function.DoubleUnaryOperator;
import java.util.function.Function;
import java.util.function.Supplier;
/**
* Represents an operation on a single {@code double}-valued operand that may
* thrown exception and produces a {@code double}-valued result. This is the
* primitive type specialization of {@link UnaryOperatorWithException} for
* {@code double}.
* <h3>General contract</h3>
* <ul>
* <li><b>{@link #applyAsDouble(double) double applyAsDouble(double operand)
* throws E}</b> - The functional method.</li>
* <li><b>uncheck</b> - Return a {@code DoubleUnaryOperator}</li>
* <li><b>lift</b> - Return a {@code DoubleUnaryOperator}</li>
* <li><b>ignore</b> - Return a {@code DoubleUnaryOperator}</li>
* </ul>
*
* @see DoubleUnaryOperator
* @param <E>
* the type of the potential exception of the function
*/
@FunctionalInterface
public interface DoubleUnaryOperatorWithException<E extends Exception>
extends PrimitiveReturnExceptionHandlerSupport<DoubleUnaryOperator, DoubleUnaryOperatorWithException<E>>,
DoubleDefaultValue {
/**
* Applies this operator to the given operand.
*
* @param operand
* the operand
* @return the operator result
* @throws E
* any exception
* @see DoubleUnaryOperator#applyAsDouble(double)
*/
double applyAsDouble(double operand) throws E;
@Override
default DoubleUnaryOperator uncheckOrIgnore(boolean uncheck) {
return operand -> {
try {
return applyAsDouble(operand);
} catch (Exception e) {
PrimitiveReturnExceptionHandlerSupport.handleException(uncheck, e, exceptionMapper());
return defaultValue();
}
};
}
/**
* Returns a composed operator that first applies the {@code before} operator to
* its input, and then applies this operator to the result. If evaluation of
* either operator throws an exception, it is relayed to the caller of the
* composed operator.
*
* @param before
* the operator to apply before this operator is applied
* @return a composed operator that first applies the {@code before} operator
* and then applies this operator
* @throws NullPointerException
* if before is null
*
* @see #andThen(DoubleUnaryOperatorWithException)
*/
default DoubleUnaryOperatorWithException<E> compose(DoubleUnaryOperatorWithException<? extends E> before) {
requireNonNull(before);
return v -> applyAsDouble(before.applyAsDouble(v));
}
/**
* Returns a composed operator that first applies this operator to its input,
* and then applies the {@code after} operator to the result. If evaluation of
* either operator throws an exception, it is relayed to the caller of the
* composed operator.
*
* @param after
* the operator to apply after this operator is applied
* @return a composed operator that first applies this operator and then applies
* the {@code after} operator
* @throws NullPointerException
* if after is null
*
* @see #compose(DoubleUnaryOperatorWithException)
*/
default DoubleUnaryOperatorWithException<E> andThen(DoubleUnaryOperatorWithException<? extends E> after) {
requireNonNull(after);
return t -> after.applyAsDouble(applyAsDouble(t));
}
/**
* Returns a unary operator that always returns its input argument.
*
* @return a unary operator that always returns its input argument
*
* @param <E>
* the exception that may be thrown
*/
static <E extends Exception> DoubleUnaryOperatorWithException<E> identity() {
return t -> t;
}
/**
* Returns a function that always throw exception.
*
* @param exceptionBuilder
* the supplier to create the exception
* @param <E>
* the type of the exception
* @return a function that always throw exception
*/
static <E extends Exception> DoubleUnaryOperatorWithException<E> failing(Supplier<E> exceptionBuilder) {
return operand -> {
throw exceptionBuilder.get();
};
}
/**
* Converts a {@code DoubleUnaryOperatorException} to a
* {@code DoubleUnaryOperator} that wraps exception to {@code RuntimeException}.
*
* @param function
* to be unchecked
* @param <E>
* the type of the potential exception
* @return the unchecked function
* @see #uncheck()
* @see #unchecked(DoubleUnaryOperatorWithException, Function)
* @throws NullPointerException
* if function is null
*/
static <E extends Exception> DoubleUnaryOperator unchecked(DoubleUnaryOperatorWithException<E> function) {
return verifyFunction(function).uncheck();
}
/**
* Converts a {@code DoubleUnaryOperatorWithException} to a
* {@code DoubleUnaryOperator} that wraps 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 <E>
* the type of the potential exception
* @return the unchecked function
* @see #uncheck()
* @see #unchecked(DoubleUnaryOperatorWithException)
* @throws NullPointerException
* if function or exceptionMapper is null
*/
static <E extends Exception> DoubleUnaryOperator unchecked(DoubleUnaryOperatorWithException<E> function,
Function<Exception, RuntimeException> exceptionMapper) {
verifyFunction(function);
verifyExceptionMapper(exceptionMapper);
return new DoubleUnaryOperatorWithException<E>() {
@Override
public double applyAsDouble(double operand) throws E {
return function.applyAsDouble(operand);
}
@Override
public Function<Exception, RuntimeException> exceptionMapper() {
return exceptionMapper;
}
}.uncheck();
}
/**
* Converts a {@code DoubleUnaryOperatorWithException} to a lifted
* {@code DoubleUnaryOperator} using {@code 0} as return value in case of error.
*
* @param function
* to be lifted
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #lift()
* @throws NullPointerException
* if function is null
*/
static <E extends Exception> DoubleUnaryOperator lifted(DoubleUnaryOperatorWithException<E> function) {
return verifyFunction(function).lift();
}
/**
* Converts a {@code DoubleUnaryOperatorWithException} to a lifted
* {@code DoubleUnaryOperator} returning {@code 0} in case of exception.
*
* @param function
* to be lifted
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @throws NullPointerException
* if function is null
*/
static <E extends Exception> DoubleUnaryOperator ignored(DoubleUnaryOperatorWithException<E> function) {
return verifyFunction(function).ignore();
}
/**
* Converts a {@code DoubleUnaryOperatorWithException} to a lifted
* {@code DoubleUnaryOperator} returning a default value in case of exception.
*
* @param function
* to be lifted
* @param defaultValue
* the default value in case of exception
* @param <E>
* the type of the potential exception
* @return the lifted function
* @see #ignore()
* @see #ignored(DoubleUnaryOperatorWithException)
* @throws NullPointerException
* if function is null
* @since 3.0.0
*/
static <E extends Exception> DoubleUnaryOperator ignored(DoubleUnaryOperatorWithException<E> function,
double defaultValue) {
verifyFunction(function);
return new DoubleUnaryOperatorWithException<E>() {
@Override
public double applyAsDouble(double operand) throws E {
return function.applyAsDouble(operand);
}
@Override
public double defaultValue() {
return defaultValue;
}
}.ignore();
}
}