Package ai.timefold.solver.core.preview.api.domain.metamodel

Interface ElementLocation

All Known Subinterfaces:

LocationInList, UnassignedLocation

public sealed interface ElementLocation
permits LocationInList, UnassignedLocation

A supertype for LocationInList and UnassignedLocation.

PlanningListVariable.allowsUnassignedValues() allows for a value to not be part of any entity's list. This introduces null into user code, and makes it harder to reason about the code. Therefore, we introduce UnassignedLocation to represent this null value, and user code must explicitly decide how to handle this case. This prevents accidental use of UnassignedLocation in places where LocationInList is expected, catching this error as early as possible.

This package and all of its contents are part of the Move Streams API, which is under development and is only offered as a preview feature. There are no guarantees for backward compatibility; any class, method or field may change or be removed without prior notice, although we will strive to avoid this as much as possible.

We encourage you to try the API and give us feedback on your experience with it, before we finalize the API. Please direct your feedback to Timefold Solver Github.

Method Summary

Modifier and Type	Method	Description
default @NonNull LocationInList	ensureAssigned()	Returns LocationInList if this location is assigned, otherwise throws an exception.
@NonNull LocationInList	ensureAssigned(@NonNull Supplier<String> messageSupplier)	Returns LocationInList if this location is assigned, otherwise throws an exception.
static @NonNull LocationInList	of(@NonNull Object entity, int index)	Create a new instance of LocationInList.
static @NonNull UnassignedLocation	unassigned()	Returns a singleton instance of UnassignedLocation.

Method Details

of

static @NonNull LocationInList of(@NonNull Object entity,
 int index)

Create a new instance of LocationInList. User code should never need to call this method.

Parameters:

entity - Entity whose PlanningListVariable contains the value.

index - 0 or higher

Returns:

never null

unassigned

static @NonNull UnassignedLocation unassigned()

Returns a singleton instance of UnassignedLocation. User code should never need to call this method.

Returns:

never null

ensureAssigned

default @NonNull LocationInList ensureAssigned()

Returns LocationInList if this location is assigned, otherwise throws an exception.

Returns:

Location of the value in an entity's PlanningListVariable.

Throws:

IllegalStateException - If this location is unassigned.

ensureAssigned

@NonNull LocationInList ensureAssigned(@NonNull Supplier<String> messageSupplier)

Returns LocationInList if this location is assigned, otherwise throws an exception.

Parameters:

messageSupplier - The message to give the exception.

Returns:

Location of the value in an entity's PlanningListVariable.

Throws:

IllegalStateException - If this location is unassigned.