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<? super 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<? super T,? extends 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<? super T> predicate)	A wrapper for a Predicate that catches exceptions and wraps them into RuntimeExceptions.
static java.lang.Runnable	_r(FunctionalCheckedExceptionWrappers.RunnableWithException runnable)	A wrapper for an equivalent of Runnable that catches exceptions and wraps them into RuntimeExceptions.
static <T> java.util.function.Supplier<T>	_s(FunctionalCheckedExceptionWrappers.SupplierWithException<? extends T> supplier)	A wrapper for a Supplier that catches exceptions and wraps them into RuntimeExceptions.
static java.lang.RuntimeException	wrappedException(java.lang.Throwable e)	Wraps a throwable with a RuntimeException.

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<? super T,? extends 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<? super 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<? extends 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:

the wrapped Supplier

_p

@Nonnull
public static <T> java.util.function.Predicate<T> _p(@Nonnull
                                                     FunctionalCheckedExceptionWrappers.PredicateWithException<? super 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:

the wrapped Predicate

_r

@Nonnull
public static java.lang.Runnable _r(@Nonnull
                                    FunctionalCheckedExceptionWrappers.RunnableWithException runnable)

A wrapper for an equivalent of Runnable that catches exceptions and wraps them into RuntimeExceptions.

Parameters:

runnable - the Runnable to wrap.

Returns:

the wrapped Predicate

Since:

3.2-ALPHA-12

wrappedException

@Nonnull
public static java.lang.RuntimeException wrappedException(@Nonnull
                                                          java.lang.Throwable e)

Wraps a throwable with a RuntimeException. Unchecked exceptions are not wrapped; IOException is wrapped with UncheckedIOException.

Parameters:

e - the exception to wrap

Returns:

the wrapped exception