Package net.groboclown.retval

Interface RetVoid

All Superinterfaces:

ProblemContainer

All Known Implementing Classes:

MonitoredReturnProblem, MonitoredReturnValue, MonitoredRetVoidOk, SimpleReturnProblem, SimpleRetVoidOk

@Immutable
public interface RetVoid
extends ProblemContainer

A simple returnable that can have problems, but no value.

Because these instances have no value, they allow for more flexibility in their functionality than the other classes.

Method Summary

Modifier and Type	Method	Description
<V> RetNullable<V>	forwardNullableProblems()	Forward this instance as a nullable with a value type, but only if it has problems.
<V> RetVal<V>	forwardProblems()	Forward this object to a typed RetVal instance.
RetVoid	forwardVoidProblems()	Forward this instance as a value-less object, but only if it has problems.
static RetVoid	fromProblem(java.util.Collection<Problem> problemSet, java.util.Collection<Problem>... problemSets)	Constructs a RetVoid instance with the collections of problems.
static RetVoid	fromProblem(Problem problem, Problem... problems)	Create a RetVoid containing the passed-in problems.
static RetVoid	fromProblems(java.util.Collection<ProblemContainer> retSet, java.util.Collection<ProblemContainer>... retSets)	Create a RetVoid containing the passed-in problems.
static RetVoid	fromProblems(ProblemContainer ret, ProblemContainer... rets)	Create a RetVoid containing the passed-in problems.
<R> RetVal<R>	map(NonnullSupplier<R> supplier)	Return a non-null RetVal value using a supplier that returns a value.
<R> RetNullable<R>	mapNullable(java.util.function.Supplier<R> supplier)	Return a non-null RetNullable value using a supplier that returns a value.
static RetVoid	ok()	Return a void object with no problems.
<R> RetVal<R>	then(NonnullSupplier<RetVal<R>> supplier)	Return a non-null RetVal value using a supplier that itself returns a RetVal.
<R> RetNullable<R>	thenNullable(NonnullSupplier<RetNullable<R>> supplier)	If there is no problem, run the supplier and return its value.
RetVoid	thenRun(java.lang.Runnable runnable)	Run the runnable if there is no problem.
RetVoid	thenVoid(NonnullSupplier<RetVoid> supplier)	Return the supplier if there is no problem.

Methods inherited from interface net.groboclown.retval.ProblemContainer

anyProblems, debugProblems, hasProblems, isOk, isProblem, joinProblemsWith, validProblems

Method Detail

ok

@Nonnull
static RetVoid ok()

Return a void object with no problems.

Returns:

a no-problem void object.

fromProblem

@SafeVarargs
@Nonnull
static RetVoid fromProblem(@Nonnull
                           java.util.Collection<Problem> problemSet,
                           @Nonnull
                           java.util.Collection<Problem>... problemSets)

Constructs a RetVoid instance with the collections of problems. This is optimized to reduce the memory load where easy. If the collection of problems has no values, then an OK value is returned instead.

Parameters:

problemSet - first collection of problems

problemSets - vararg optional problems that should be included in this object.

Returns:

a RetVoid with all the given problems.

fromProblem

@Nonnull
static RetVoid fromProblem(@Nullable
                           Problem problem,
                           Problem... problems)

Create a RetVoid containing the passed-in problems. If there was no problem in any of the arguments, then this will return a no-problem value.

Parameters:

problem - initial problem

problems - vararg optional list of problems.

Returns:

a new void instance, possibly without problems.

fromProblems

@SafeVarargs
@Nonnull
static RetVoid fromProblems(@Nonnull
                            java.util.Collection<ProblemContainer> retSet,
                            @Nonnull
                            java.util.Collection<ProblemContainer>... retSets)

Create a RetVoid containing the passed-in problems. If there was no problem in any of the arguments, then this will return a no-problem value.

Parameters:

retSet - primary collection of problem containers.

retSets - vararg optional problem container collections.

Returns:

a new void instance, possibly without problems.

fromProblems

@Nonnull
static RetVoid fromProblems(@Nullable
                            ProblemContainer ret,
                            @Nonnull
                            ProblemContainer... rets)

Create a RetVoid containing the passed-in problems. If there was no problem in any of the arguments, then this will return a no-problem value.

Parameters:

ret - a problem container

rets - an optional list of problem containers.

Returns:

a new void instance, possibly without problems.

then

@Nonnull
<R> RetVal<R> then(@Nonnull
                   NonnullSupplier<RetVal<R>> supplier)

Return a non-null RetVal value using a supplier that itself returns a RetVal. The supplier is called only if this object has no problem.

Type Parameters:

R - type of the returned value.

Parameters:

supplier - functional object that returns a RetVal.

Returns:

the problem of the current value, if it is a problem, or the object returned by the supplier.

map

@Nonnull
<R> RetVal<R> map(@Nonnull
                  NonnullSupplier<R> supplier)

Return a non-null RetVal value using a supplier that returns a value. The supplier is called only if this object has no problem.

Formally, this doesn't "map" one value to another. However, for symmetry with the other Ret classes, it is here called map.

Type Parameters:

R - return value type

Parameters:

supplier - functional object that returns a non-null value.

Returns:

a RetVal, either a problem if this object has a problem, or the value returned by the supplier.

thenNullable

@Nonnull
<R> RetNullable<R> thenNullable(@Nonnull
                                NonnullSupplier<RetNullable<R>> supplier)

If there is no problem, run the supplier and return its value. Otherwise, return this object's problems.

Type Parameters:

R - return value type

Parameters:

supplier - supplier of the return value; run only if this object has no problems.

Returns:

the problems in this object, or the supplier's return value.

mapNullable

@Nonnull
<R> RetNullable<R> mapNullable(@Nonnull
                               java.util.function.Supplier<R> supplier)

Return a non-null RetNullable value using a supplier that returns a value. The supplier is called only if this object has no problem.

Formally, this doesn't "map" one value to another. However, for symmetry with the other Ret classes, it is here called map.

Type Parameters:

R - return value type

Parameters:

supplier - functional object that returns a non-null value.

Returns:

a RetVal, either a problem if this object has an problem, or the value returned by the supplier.

thenVoid

@Nonnull
RetVoid thenVoid(@Nonnull
                 NonnullSupplier<RetVoid> supplier)

Return the supplier if there is no problem.

Parameters:

supplier - function to run

Returns:

this object if there are problems in this object, otherwise the supplier's return value.

thenRun

@Nonnull
RetVoid thenRun(@Nonnull
                java.lang.Runnable runnable)

Run the runnable if there is no problem.

Parameters:

runnable - function to run

Returns:

this object.

forwardProblems

@Nonnull
<V> RetVal<V> forwardProblems()

Forward this object to a typed RetVal instance. This will only work when the instance has problems.

The most common use case is when a value construction requires multiple steps, and an early step requires early exit from the function. This allows a memory efficient type casting of the problems to the construction function's type.

Type Parameters:

V - altered type.

Returns:

the type-altered version

Throws:

java.lang.IllegalStateException - if this instance does not have problems.

forwardNullableProblems

@Nonnull
<V> RetNullable<V> forwardNullableProblems()

Forward this instance as a nullable with a value type, but only if it has problems. If it does not have problems, then a runtime exception is thrown.

The most common use case is when a value construction requires multiple steps, and an early step requires early exit from the function. This allows a memory efficient type casting of the problems to the construction function's type.

Type Parameters:

V - destination type

Returns:

the value, only if this instance has problems.

forwardVoidProblems

@Nonnull
RetVoid forwardVoidProblems()

Forward this instance as a value-less object, but only if it has problems. If it does not have problems, then a runtime exception is thrown.

The most common use case is when a value construction requires multiple steps, and an early step requires early exit from the function. This allows a memory efficient type casting of the problems to the construction function's type.

Returns:

the value, only if this instance has problems.