Interface SolutionManager

All Known Implementing Classes:

SimpleSolutionManager

public interface SolutionManager

SolutionManager

Abstraction that stores the partial substitutions produced by a back‑tracking evaluation engine. For each depth of the search tree (level) it keeps:

• the Spliterator enumerating the candidate substitutions of that sub‑query,
• the set of variables that will be newly bound when a candidate wins.

The interface lets the engine:

• read the current (live) substitution getCurrentSolution(),
• obtain a defensive snapshot via copyCurrentSolution(),
• advance or register choice‑points (next(int), add(int, Spliterator, Collection)),
• expose internal spliterators for work‑stealing / splitting,
• clone the whole structure so each branch explores independently.

Concurrency and mutability: the object returned by getCurrentSolution() is a live view; it changes as soon as next(int) succeeds. Never cache or publish it outside the evaluation loop. Use copyCurrentSolution() when you need an immutable snapshot.

Author:

Guillaume Perution-Kihli

Method Summary

Modifier and Type	Method	Description
void	add(int level, Spliterator<Substitution> substitutions, Collection<Variable> newVariables)	Register the spliterator that will supply substitutions for level together with the list of variables that those substitutions can bind for the first time.
Substitution	copyCurrentSolution()	Returns a stable snapshot of the current solution.
SolutionManager	deepCopy()	Creates an independent copy of this solution manager.
Substitution	getCurrentSolution()	Returns the substitution that is currently valid at all explored levels.
Spliterator<Substitution>	getSpliterator(int level)	Returns the spliterator registered for a level.
boolean	next(int level)	Advance the iterator at level so the next candidate substitution (if any) is merged into the global solution.
void	pruneOtherIterators(int level)	Prunes every stored iterator except the selected level.
void	replaceSpliterator(int level, Spliterator<Substitution> newSpliterator)	Replaces the spliterator registered for a level.

Method Details

getCurrentSolution

Substitution getCurrentSolution()

Returns the substitution that is currently valid at all explored levels.

Live view: subsequent calls to next(int) may mutate and/or invalidate the content. Clone it with copyCurrentSolution() if you need to keep a stable version.

Returns:

the current live substitution

copyCurrentSolution

Substitution copyCurrentSolution()

Returns a stable snapshot of the current solution.

Returns:

a defensive copy of the current solution (safe to keep).

next

boolean next(int level)

Advance the iterator at level so the next candidate substitution (if any) is merged into the global solution.

Parameters:

level - depth in the search tree (0‑based)

Returns:

true if a compatible substitution exists, false otherwise.

add

void add(int level,
 Spliterator<Substitution> substitutions,
 Collection<Variable> newVariables)

Register the spliterator that will supply substitutions for level together with the
list of variables that those substitutions can bind for the first time.

Parameters:

level - depth in the search tree (0-based)

substitutions - the substitutions available at that level

newVariables - the variables that may become bound at that level

getSpliterator

Spliterator<Substitution> getSpliterator(int level)

Returns the spliterator registered for a level.

Parameters:

level - depth in the search tree (0-based)

Returns:

the spliterator associated with level, or null.

replaceSpliterator

void replaceSpliterator(int level,
 Spliterator<Substitution> newSpliterator)

Replaces the spliterator registered for a level. Replace the spliterator stored for level.

Parameters:

level - depth in the search tree (0-based)

newSpliterator - the replacement spliterator

pruneOtherIterators

void pruneOtherIterators(int level)

Prunes every stored iterator except the selected level. Remove (or empty) every level that is not equal to level.

Parameters:

level - the level to keep

deepCopy

SolutionManager deepCopy()

Creates an independent copy of this solution manager.

Returns:

an independent copy of this manager so that another branch can evolve in parallel without interference.