Package it.tidalwave.util

Class FunctionalCheckedExceptionWrappers

java.lang.Object

it.tidalwave.util.FunctionalCheckedExceptionWrappers

public final class FunctionalCheckedExceptionWrappers
extends java.lang.Object

A collections of utility methods for simplifying the syntax of lambda expressions with APIs that don't accept checked exceptions (such as Stream): they provide wrapped functions that have no checked exception in the signature and whose implementation delegates to the original function wrapping an eventual checked exception into a RuntimeException. For instance, given the following method that could not be used as a Stream.filter(Predicate) argument:

   private boolean matchEven (final int number)
           throws Exception
     {
       if (number == 13)
         {
           throw new Exception("13!");
         }

       return number % 2 == 0;
     }
 

working code can be written as:

   try
     {
       List<Integer> numbers = IntStream.rangeClosed(1, 20)
                                        .mapToObj(Integer::valueOf)
                                        .filter(_p(this::matchEven)) // note the wrapper here
                                        .collect(Collectors.toList());
       ...
     }
   catch (RuntimeException e)
     {
       ...
     }
 

Any checked exception is wrapped by a RuntimeException, but IOException is wrapped by a UncheckedIOException.

Since:

3.2-ALPHA-1

Author:

Fabrizio Giudici

Status: draft API

Constructor Summary

Constructors

Constructor	Description
FunctionalCheckedExceptionWrappers()

Method Summary

Modifier and Type	Method	Description
static <T> java.util.function.Consumer<T>	_c(FunctionalCheckedExceptionWrappers.ConsumerWithException<T> consumer)	A wrapper for a Consumer that catches exceptions and wraps them into RuntimeExceptions.
static <T,R> java.util.function.Function<T,R>	_f(FunctionalCheckedExceptionWrappers.FunctionWithException<T,R> function)	A wrapper for a Function that catches exceptions and wraps them into RuntimeExceptions.
static <T> java.util.function.Predicate<T>	_p(FunctionalCheckedExceptionWrappers.PredicateWithException<T> predicate)	A wrapper for a Predicate that catches exceptions and wraps them into RuntimeExceptions.
static <T> java.util.function.Supplier<T>	_s(FunctionalCheckedExceptionWrappers.SupplierWithException<T> supplier)	A wrapper for a Supplier that catches exceptions and wraps them into RuntimeExceptions.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FunctionalCheckedExceptionWrappers

public FunctionalCheckedExceptionWrappers()

Method Detail

_f

@Nonnull
public static <T,R> java.util.function.Function<T,R> _f(@Nonnull
                                                                    FunctionalCheckedExceptionWrappers.FunctionWithException<T,R> function)

A wrapper for a Function that catches exceptions and wraps them into RuntimeExceptions.

Type Parameters:

T - the type of the function argument

R - the type of the function return value

Parameters:

function - the Function to wrap.

Returns:

the wrapped Function

_c

@Nonnull
public static <T> java.util.function.Consumer<T> _c(@Nonnull
                                                    FunctionalCheckedExceptionWrappers.ConsumerWithException<T> consumer)

A wrapper for a Consumer that catches exceptions and wraps them into RuntimeExceptions.

Type Parameters:

T - the type of the Consumer argument

Parameters:

consumer - the Consumer to wrap.

Returns:

the wrapped Consumer

_s

@Nonnull
public static <T> java.util.function.Supplier<T> _s(@Nonnull
                                                    FunctionalCheckedExceptionWrappers.SupplierWithException<T> supplier)

A wrapper for a Supplier that catches exceptions and wraps them into RuntimeExceptions.

Type Parameters:

T - the type of the Supplier argument

Parameters:

supplier - the Supplier to wrap.

Returns:

åthe wrapped Supplier

_p

@Nonnull
public static <T> java.util.function.Predicate<T> _p(@Nonnull
                                                     FunctionalCheckedExceptionWrappers.PredicateWithException<T> predicate)

A wrapper for a Predicate that catches exceptions and wraps them into RuntimeExceptions.

Type Parameters:

T - the type of the Predicate argument

Parameters:

predicate - the Predicate to wrap.

Returns:

åthe wrapped Predicate