org.oddjob.arooa.utils

Class Try<T>

java.lang.Object

org.oddjob.arooa.utils.Try<T>

Type Parameters:

T -

public abstract class Try<T>
extends Object

A Functional Success/Failure thing.

Author:

rob

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	Try.Func<T,R,E extends Throwable> A Function that throws an Exception.

Constructor Summary

Constructors

Constructor and Description
Try()

Method Summary

Modifier and Type	Method and Description
static <U> Try<U>	fail(Throwable e) Create a try wrapping an Exception.
abstract <U> Try<U>	flatMap(Function<? super T,? extends Try<U>> f) Apply a function to the Try that itself returns a Try.
abstract <U> Try<U>	map(Function<? super T,? extends U> f) Apply a function to the Try.
abstract Try<T>	mapFailure(Function<? super Throwable,? extends Throwable> f) Map a failure by applying the exception mapping function.
static <U> Try<U>	of(U value) Create a Try from a value.
static <U> Try<U>	ofNonNull(U value, String m) A try with a null check.
abstract Try<T>	onFailure(Consumer<? super Throwable> f)
abstract Try<T>	onSuccess(Consumer<? super T> s)
abstract T	orElseThrow() Recover the value or throw an Exception.
abstract <E extends Throwable> T	orElseThrow(Function<? super Throwable,E> f) Recover the value or throw an exception created by applying the exception mapping function to a failure.
abstract T	recover(Function<? super Throwable,? extends T> f) Recover the value or apply a function to the exception to get result.
abstract <U> Try<U>	trying(Try.Func<? super T,? extends U,?> f) Try a Function that might throw a Exception.

Methods inherited from class java.lang.Object

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

Constructor Detail

Try

public Try()

Method Detail

of

public static <U> Try<U> of(U value)

Create a Try from a value. At the moment the value may be null. Not sure if this is a good idea.

Parameters:

value - A value. May be null.

Returns:

A Try wrapping the value.

ofNonNull

public static <U> Try<U> ofNonNull(U value,
                                   String m)

A try with a null check. If the value is null, the Try is a wrapped NullPointerException.

Parameters:

value - The value.

m - A message that will be added to the NullPointerException if the value is null. May be null.

Returns:

A Try wrapping the value or a NullPointerException.

fail

public static <U> Try<U> fail(Throwable e)

Create a try wrapping an Exception.

Parameters:

e - The Exception. Must not be null.

Returns:

A Try wrapping the Exception.

orElseThrow

public abstract T orElseThrow()
                       throws RuntimeException

Recover the value or throw an Exception.

Returns:

The value. May be null.

Throws:

Exception - if the Try resulted in a Failure.

RuntimeException

orElseThrow

public abstract <E extends Throwable> T orElseThrow(Function<? super Throwable,E> f)
                                             throws E extends Throwable

Recover the value or throw an exception created by applying the exception mapping function to a failure.

Parameters:

f - The exception mapping function.

Returns:

The value if a success.

Throws:

E - The type of the resultant exception when a failure.

E extends Throwable

recover

public abstract T recover(Function<? super Throwable,? extends T> f)

Recover the value or apply a function to the exception to get result.

Parameters:

f - A function taking the exception.

Returns:

A value.

map

public abstract <U> Try<U> map(Function<? super T,? extends U> f)

Apply a function to the Try. The function will only be applied if the Try is currently a Success.

Parameters:

f - The Function to apply.

Returns:

A new Try wrapping the result of applying the function, or a previous Failure.

mapFailure

public abstract Try<T> mapFailure(Function<? super Throwable,? extends Throwable> f)

Map a failure by applying the exception mapping function. A success will be left unchanged.

Parameters:

f - The failure mapping function.

Returns:

The resultant try.

flatMap

public abstract <U> Try<U> flatMap(Function<? super T,? extends Try<U>> f)

Apply a function to the Try that itself returns a Try. The function will only be applied if the Try is currently a Success.

Parameters:

f - The Function to apply.

Returns:

A new Try wrapping the result of applying the function, or a previous Failure, or a new Failure from the function.

trying

public abstract <U> Try<U> trying(Try.Func<? super T,? extends U,?> f)

Try a Function that might throw a Exception.

Parameters:

f - The Function to apply.

Returns:

A new Try wrapping the result of applying the function, or a previous Failure, or a new Failure from the function.

onSuccess

public abstract Try<T> onSuccess(Consumer<? super T> s)

onFailure

public abstract Try<T> onFailure(Consumer<? super Throwable> f)