solve-concurrent/it.unibo.tuprolog.solve.concurrent.fsm/StateHalt

StateHalt

data class StateHalt(val exception: ResolutionException, val context: ConcurrentExecutionContext) : AbstractState, ExceptionalState, EndState

The terminal, unrecoverable EndState a branch reaches when exception could not be handled by any enclosing catch/3 (or was a timeout, see AbstractState): solution is a Solution.Halt. Reaching a StateHalt does not, by itself, stop sibling branches of the search tree -- it is up to the coroutine driving this branch (and, ultimately, whoever consumes the resolution's solution channel) to decide whether a halted branch should abort the whole resolution.

Constructors

StateHalt

constructor(exception: ResolutionException, context: ConcurrentExecutionContext)

Properties

context

open override val context: ConcurrentExecutionContext

The execution context this state operates on.

exception

open override val exception: ResolutionException

The exception this state needs to propagate/handle.

isEndState

open val isEndState: Boolean

Whether this state is a terminal one for the current branch, i.e. an EndState.

solution

open override val solution: Solution

The Solution produced by this branch of the search tree.

Functions

asEndState

open fun asEndState(): EndState

This state as an EndState, or null if isEndState is false.

castToEndState

open fun castToEndState(): EndState

This state as an EndState.

clone

open override fun clone(context: ConcurrentExecutionContext = this.context): StateHalt

Returns a copy of this state, replacing context with the given one (defaulting to the current context).

open override fun next(): Iterable<State>

Computes every state this branch may transition into from here, one per alternative (matching clause, disjunct, primitive solution, ...) available at this point; empty only for EndStates. Each element is meant to be explored independently (and, in :solve-concurrent's solver, concurrently) of the others.