Package io.github.suppierk.java.util

Interface Try<T>

Type Parameters:

T - the class of the value

All Known Implementing Classes:

Try.Failure, Try.Success

public interface Try<T>

A container object that contains either a value or exception.

If a value is present, isSuccess() will return true and get() will return the value. If exception occurred, isFailure() will return true and get() will return first occurred exception.

Additional methods that depend on the presence or absence of a contained value are provided, such as orElse() (return a default value if value not present) and ifSuccess(ThrowableConsumer) (execute a block of code if the value is present) or ifFailure(ThrowableConsumer) (execute a block of code if the exception is present).

This is a value-based class; use of identity-sensitive operations (including reference equality (==), identity hash code, or synchronization) on instances of Try may have unpredictable results and should be avoided.

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Try.Failure<T>	A container object which contains exception.
static class	Try.Success<T>	A container object which contains value.

Method Summary

Modifier and Type	Method	Description
static <T> Try<T>	failure(java.lang.Throwable throwable)	Returns a Try with the specified exception.
Try<T>	filter(ThrowablePredicate<? super T> predicate)	If a value is present, and the value matches the given predicate, return a Try describing the value, otherwise return a failed Try.
<U> Try<U>	flatMap(ThrowableFunction<? super T,Try<U>> mapper)	If a value is present, apply the provided Try-bearing mapping function to it, return that result, otherwise return a failed Try.
static <T> Try<T>	fromOptional(java.util.Optional<T> optional)	Returns a Try created from specified Optional.
T	get()	If this is Try.Success, returns the value, if this is Try.Failure, throws the exception stored as unchecked.
void	ifFailure(ThrowableConsumer<java.lang.Throwable> consumer)	If an exception is present, invoke the specified consumer with the value, otherwise do nothing.
void	ifSuccess(ThrowableConsumer<? super T> consumer)	If a value is present, invoke the specified consumer with the value, otherwise do nothing.
boolean	isFailure()
boolean	isSuccess()
<U> Try<U>	map(ThrowableFunction<? super T,? extends U> mapper)	If a value is present, apply the provided mapping function to it, and if the result is non-null, return a Try describing the result.
static <T> Try<T>	of(ThrowableSupplier<T> supplier)	Returns a Try by invoking specified supplier.
default T	orElse(java.util.function.Supplier<? extends T> other)	Return the value if present, otherwise invoke other and return the result of that invocation.
default T	orElse(T other)	Return the value if present, otherwise return other.
Try<T>	orElseTry(ThrowableSupplier<T> supplier)	Continue Try composition by providing alternative ways to compute desired value
static <T> Try<T>	success(T value)	Returns a Try with the specified value.
java.util.Optional<T>	toOptional()	Convert this Try to Optional without preserving exception information.

Method Detail

of

static <T> Try<T> of(ThrowableSupplier<T> supplier)

Returns a Try by invoking specified supplier.

Type Parameters:

T - the class of the value

Parameters:

supplier - the supplier to retrieve the value

Returns:

a Try.Success with the value retrieved successfully or Try.Failure

fromOptional

static <T> Try<T> fromOptional(java.util.Optional<T> optional)

Returns a Try created from specified Optional.

Type Parameters:

T - the class of the value

Parameters:

optional - the Optional to be present

Returns:

a Try.Success with the value if it was present otherwise a Try.Failure with NoSuchElementException

Throws:

java.lang.NullPointerException - if optional is null

success

static <T> Try<T> success(T value)

Returns a Try with the specified value.

Type Parameters:

T - the class of the value

Parameters:

value - the value to be present

Returns:

a Try.Success with the value

Throws:

java.lang.NullPointerException - if value is null

failure

static <T> Try<T> failure(java.lang.Throwable throwable)

Returns a Try with the specified exception.

Type Parameters:

T - the class of the value

Parameters:

throwable - the value to be present, which must be non-null

Returns:

a Try.Failure with the exception

Throws:

java.lang.NullPointerException - if throwable is null

get

T get()

If this is Try.Success, returns the value, if this is Try.Failure, throws the exception stored as unchecked.

Returns:

the value held by this Try.Success

See Also:

isSuccess(), isFailure()

isSuccess

boolean isSuccess()

Returns:

true if there is a value present, otherwise false

isFailure

boolean isFailure()

Returns:

true if there is an exception present, otherwise false

ifSuccess

void ifSuccess(ThrowableConsumer<? super T> consumer)

If a value is present, invoke the specified consumer with the value, otherwise do nothing.

Parameters:

consumer - block to be executed if a value is present

ifFailure

void ifFailure(ThrowableConsumer<java.lang.Throwable> consumer)

If an exception is present, invoke the specified consumer with the value, otherwise do nothing.

Parameters:

consumer - block to be executed if an exception is present

filter

Try<T> filter(ThrowablePredicate<? super T> predicate)

If a value is present, and the value matches the given predicate, return a Try describing the value, otherwise return a failed Try.

Parameters:

predicate - a predicate to apply to the value, if present

Returns:

a Try.Success describing the value of this Try if a value is present and the value matches the given predicate, otherwise a Try.Failure

map

<U> Try<U> map(ThrowableFunction<? super T,? extends U> mapper)

If a value is present, apply the provided mapping function to it, and if the result is non-null, return a Try describing the result. Otherwise, return a failed Try.

Type Parameters:

U - The type of the result of the mapping function

Parameters:

mapper - a mapping function to apply to the value, if present

Returns:

a Try.Success describing the result of applying a mapping function to the value of this Try, if a value is present, otherwise a Try.Failure

flatMap

<U> Try<U> flatMap(ThrowableFunction<? super T,Try<U>> mapper)

If a value is present, apply the provided Try-bearing mapping function to it, return that result, otherwise return a failed Try. This method is similar to map(ThrowableFunction), but the provided mapper is one whose result is already a Try, and if invoked, flatMap does not wrap it with an additional Try.

Type Parameters:

U - The type parameter to the Try returned by

Parameters:

mapper - a mapping function to apply to the value, if present the mapping function

Returns:

the result of applying a Try-bearing mapping function to the value of this Try, if a value is present, otherwise a Try.Failure

toOptional

java.util.Optional<T> toOptional()

Convert this Try to Optional without preserving exception information.

Returns:

new Optional containing value or Optional.empty() if there was an exception

orElseTry

Try<T> orElseTry(ThrowableSupplier<T> supplier)

Continue Try composition by providing alternative ways to compute desired value

Parameters:

supplier - to invoke in case of failure.

Returns:

new Try instance

orElse

default T orElse(T other)

Return the value if present, otherwise return other.

Parameters:

other - the value to be returned if there is a failure, may be null

Returns:

the value, if present, otherwise other

orElse

default T orElse(java.util.function.Supplier<? extends T> other)

Return the value if present, otherwise invoke other and return the result of that invocation.

Parameters:

other - a Supplier whose result is returned if no value is present

Returns:

the value if present otherwise the result of other.get()

Throws:

java.lang.NullPointerException - if value is not present and other is null