com.atlassian.crowd.common.util

Interface ThrowingFunction<T,R>

Type Parameters:

T - input parameter type

R - result type

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface ThrowingFunction<T,R>

An alternative to Java's Function, that declares a checked exception. This helps with handling checked exceptions in lambdas.

Method Summary

Modifier and Type	Method and Description
R	apply(T input) Check Function.apply(Object)
static <T,R> Function<T,R>	unchecked(ThrowingFunction<T,R> lambda) Wraps a lambda by handling checked Exception - converting it into RuntimeException
static <T,R> Function<T,R>	unchecked(ThrowingFunction<T,R> lambda, Function<Exception,? extends RuntimeException> exceptionMapper) Wraps a lambda by handling checked Exception.

Method Detail

apply

R apply(T input)
 throws Exception

Check Function.apply(Object)

Parameters:

input - function input parameter of type T

Returns:

function result

Throws:

Exception - a checked exception might be thrown

unchecked

static <T,R> Function<T,R> unchecked(ThrowingFunction<T,R> lambda)

Wraps a lambda by handling checked Exception - converting it into RuntimeException

Type Parameters:

T - lambda input type

R - lambda result type

Parameters:

lambda - lambda function

Returns:

function that does not declare checked exceptions

unchecked

static <T,R> Function<T,R> unchecked(ThrowingFunction<T,R> lambda,
                                     Function<Exception,? extends RuntimeException> exceptionMapper)

Wraps a lambda by handling checked Exception. A custom mapper should be provided for transforming the caught checked exception into a RuntimeException

Type Parameters:

T - lambda input type

R - lambda result type

Parameters:

lambda - lambda function

exceptionMapper - mapper, transforming checked exception into runtime

Returns:

function that does not declare checked exceptions