com.github.charithe.fjp

Class Try<T>

java.lang.Object

com.github.charithe.fjp.Try<T>

Type Parameters:

T - Type of success value

public class Try<T>
extends Object

Emulates the Scala Try interface

See Also:

Scala Try

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	Try.CallingFailureOnSuccessValue
static class	Try.CallingSuccessOnFailureValue
static interface	Try.FunctionThrowingException<A>
static class	Try.LambdaException
static class	Try.UnmatchedFilterPredicate

Method Summary

Modifier and Type	Method and Description
static <A> Try<A>	doTry(Try.FunctionThrowingException<A> fn) Create a Try object from a function that could potentially throw an exception and fail.
Throwable	failure() Returns the failure value if this is a failure.
Try<T>	filter(java.util.function.Predicate<T> predicate) Apply the predicate to the success value to determine whether this should really be a failure
<A> Try<A>	flatMap(java.util.function.Function<T,Try<A>> fn) Perform a flatmap over this instance
void	foreach(java.util.function.Consumer<T> consumer) Apply the supplied function to the success value if this is a success
static <A> Try<A>	fromFailure(Throwable failureVal) Create a failure instance of Try
static <A> Try<A>	fromSuccess(A successVal) Create a success instance of Try
T	get() Return the success value if this is a success or throw the failure value if this is a failure
T	getOrElse(T defaultVal) Return the success value or the supplied default if this is a failure instance
boolean	isFailure() Returns true if this instance holds a failure value
boolean	isSuccess() Returns true if this instance holds a success value
<A> Try<A>	map(java.util.function.Function<T,A> fn) Perform a map over this instance
Try<T>	orElse(Try<T> defaultVal) Return this instance if it is a success instance.
T	success() Returns the success value if this is a success.
Optional<T>	toOptional() Convert this to an Optional

Methods inherited from class java.lang.Object

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

Method Detail

isSuccess

public boolean isSuccess()

Returns true if this instance holds a success value

Returns:

boolean

isFailure

public boolean isFailure()

Returns true if this instance holds a failure value

Returns:

boolean

success

public T success()

Returns the success value if this is a success. Otherwise, throws an exception.

Returns:

Success value if present

Throws:

Try.CallingSuccessOnFailureValue

failure

public Throwable failure()

Returns the failure value if this is a failure. Otherwise, throws an exception.

Returns:

Failure value if present

Throws:

Try.CallingFailureOnSuccessValue

flatMap

public <A> Try<A> flatMap(java.util.function.Function<T,Try<A>> fn)

Perform a flatmap over this instance

Type Parameters:

A - Return type of flatmap function

Parameters:

fn - flatmap function

Returns:

If this is a success, result of applying the flatmap function. Otherwise, the failure value

map

public <A> Try<A> map(java.util.function.Function<T,A> fn)

Perform a map over this instance

Type Parameters:

A - Return type of map function

Parameters:

fn - map function

Returns:

If this is a success, result of applying the map function. Otherwise, the failure value

get

public T get()
      throws Throwable

Return the success value if this is a success or throw the failure value if this is a failure

Returns:

success value if this is a success instance

Throws:

Throwable - if this is a failure instance

getOrElse

public T getOrElse(T defaultVal)

Return the success value or the supplied default if this is a failure instance

Parameters:

defaultVal - Default value to return in case of failure

Returns:

success value or the supplied default

orElse

public Try<T> orElse(Try<T> defaultVal)

Return this instance if it is a success instance. Otherwise, return the supplied default.

Parameters:

defaultVal - Default value to return in case this is a failure

Returns:

this instance or the supplied default

toOptional

public Optional<T> toOptional()

Convert this to an Optional

Returns:

Optional containing the success value or Optional.empty in case this is a failure.

filter

public Try<T> filter(java.util.function.Predicate<T> predicate)

Apply the predicate to the success value to determine whether this should really be a failure

Parameters:

predicate - Predicate to apply

Returns:

this object if it is a failure. If this is a success, return success if the predicate is satisfied or return failure otherwise.

foreach

public void foreach(java.util.function.Consumer<T> consumer)

Apply the supplied function to the success value if this is a success

Parameters:

consumer - Function to apply

fromSuccess

public static <A> Try<A> fromSuccess(A successVal)

Create a success instance of Try

Type Parameters:

A - Type of the success value

Parameters:

successVal - success value to wrap inside the Try

Returns:

Try object that returns true on calls to isSuccess()

fromFailure

public static <A> Try<A> fromFailure(Throwable failureVal)

Create a failure instance of Try

Type Parameters:

A - Type of the success value if this were a success

Parameters:

failureVal - failure value to wrap inside the Try

Returns:

Try object that return true on calls to isFailure()

doTry

public static <A> Try<A> doTry(Try.FunctionThrowingException<A> fn)

Create a Try object from a function that could potentially throw an exception and fail. If the function is successful, the return value will be Try containing the success. If an exception is thrown, the return value will be a Try object containing the failure.

Type Parameters:

A - Type of the return value from the function

Parameters:

fn - Function that could potentially throw an exception

Returns:

Try object containing the result of the function or the exception thrown