Package ai.timefold.solver.core.impl.heuristic.selector.value.decorator

Class FilteringValueRangeSelector<Solution_>

java.lang.Object

ai.timefold.solver.core.impl.heuristic.selector.AbstractSelector<Solution_>

ai.timefold.solver.core.impl.heuristic.selector.AbstractDemandEnabledSelector<Solution_>

ai.timefold.solver.core.impl.heuristic.selector.value.decorator.FilteringValueRangeSelector<Solution_>

Type Parameters:

Solution_ - the solution type

All Implemented Interfaces:

IterableSelector<Solution_,Object>, Selector<Solution_>, IterableValueSelector<Solution_>, ValueSelector<Solution_>, PhaseLifecycleListener<Solution_>, SolverLifecycleListener<Solution_>, Iterable<Object>, EventListener

public final class FilteringValueRangeSelector<Solution_>
extends AbstractDemandEnabledSelector<Solution_>
implements IterableValueSelector<Solution_>

The decorator returns a list of reachable values for a specific value. It enables the creation of a filtering tier when using entity-provided value ranges, ensuring only valid and reachable values are returned. A value is considered reachable to another value if both exist within their respective entity value ranges.

The decorator can only be applied to list variables.

e1 = entity_range[v1, v2, v3] e2 = entity_range[v1, v4] v1 = [v2, v3, v4] v2 = [v1, v3] v3 = [v1, v2] v4 = [v1]

This node is currently used by the ListChangeMoveSelector and ListSwapMoveSelector selectors. To illustrate its usage, let’s assume how moves are generated for the list swap type. Initially, the swap move selector used a left value selector to choose a value. After that, it uses a right value selector to choose another value to swap them.

Based on the previously described process and the current goal of this node, we can observe that once a value is selected using the left value selector, the right node can filter out all non-reachable values and generate a valid move. A move is considered valid only if both entities accept each other's values. The filtering process of invalid values allows the solver to explore the solution space more efficiently.

See Also:

• ListChangeMoveSelectorFactory
• DestinationSelectorFactory
• ListSwapMoveSelectorFactory
• ValueSelectorFactory

Field Summary

Fields inherited from class ai.timefold.solver.core.impl.heuristic.selector.AbstractSelector

logger, phaseLifecycleSupport, workingRandom

Constructor Summary

Constructors

Constructor	Description
FilteringValueRangeSelector(IterableValueSelector<Solution_> nonReplayingValueSelector, IterableValueSelector<Solution_> replayingValueSelector, boolean randomSelection, boolean checkSourceAndDestination)

Method Summary

Modifier and Type	Method	Description
Iterator<Object>	endingIterator(Object entity)	If Selector.isNeverEnding() is true, then ValueSelector.iterator(Object) will never end.
boolean	equals(Object other)
SelectionCacheType	getCacheType()	Unless this selector itself caches, this returns SelectionCacheType.JUST_IN_TIME, even if a selector child caches.
IterableValueSelector<Solution_>	getChildValueSelector()
<T> SelectionSorter<Solution_,T>	getSelectionSorter()	Returns the selection sorter applied to the node.
long	getSize()	A random JIT Selector with Selector.isNeverEnding() true should return a size as if it would be able to return each distinct element only once, because the size can be used in SelectionProbabilityWeightFactory.
long	getSize(Object entity)	Similar to IterableSelector.getSize(), but requires an entity.
GenuineVariableDescriptor<Solution_>	getVariableDescriptor()
int	hashCode()
boolean	isCountable()	If false, then Selector.isNeverEnding() is true.
boolean	isNeverEnding()	Is true if Selector.isCountable() is false or if this selector is in random order (for most cases).
Iterator<Object>	iterator()
Iterator<Object>	iterator(Object entity)	Similar to Iterable.iterator(), but requires an entity.
void	phaseEnded(AbstractPhaseScope<Solution_> phaseScope)
void	phaseStarted(AbstractPhaseScope<Solution_> phaseScope)
void	solvingStarted(SolverScope<Solution_> solverScope)

Methods inherited from class ai.timefold.solver.core.impl.heuristic.selector.AbstractSelector

solvingEnded, stepEnded, stepStarted

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach

Methods inherited from interface ai.timefold.solver.core.impl.heuristic.selector.IterableSelector

spliterator

Methods inherited from interface ai.timefold.solver.core.impl.phase.event.PhaseLifecycleListener

stepEnded, stepStarted

Methods inherited from interface ai.timefold.solver.core.impl.solver.event.SolverLifecycleListener

solvingEnded, solvingError

Constructor Details

FilteringValueRangeSelector

public FilteringValueRangeSelector(IterableValueSelector<Solution_> nonReplayingValueSelector,
 IterableValueSelector<Solution_> replayingValueSelector,
 boolean randomSelection,
 boolean checkSourceAndDestination)

Method Details

solvingStarted

public void solvingStarted(SolverScope<Solution_> solverScope)

Specified by:

solvingStarted in interface SolverLifecycleListener<Solution_>

Overrides:

solvingStarted in class AbstractSelector<Solution_>

phaseStarted

public void phaseStarted(AbstractPhaseScope<Solution_> phaseScope)

Specified by:

phaseStarted in interface PhaseLifecycleListener<Solution_>

Overrides:

phaseStarted in class AbstractSelector<Solution_>

phaseEnded

public void phaseEnded(AbstractPhaseScope<Solution_> phaseScope)

Specified by:

phaseEnded in interface PhaseLifecycleListener<Solution_>

Overrides:

phaseEnded in class AbstractSelector<Solution_>

getChildValueSelector

public IterableValueSelector<Solution_> getChildValueSelector()

getSelectionSorter

public <T> SelectionSorter<Solution_,T> getSelectionSorter()

Description copied from interface: ValueSelector

Returns the selection sorter applied to the node. By default, it returns null and must be overridden by the child class if necessary.

Specified by:

getSelectionSorter in interface ValueSelector<Solution_>

Type Parameters:

T - the sorter value type.

Returns:

the selection sorter.

getCacheType

public SelectionCacheType getCacheType()

Description copied from interface: Selector

Unless this selector itself caches, this returns SelectionCacheType.JUST_IN_TIME, even if a selector child caches.

Specified by:

getCacheType in interface Selector<Solution_>

Overrides:

getCacheType in class AbstractSelector<Solution_>

Returns:

never null

getVariableDescriptor

public GenuineVariableDescriptor<Solution_> getVariableDescriptor()

Specified by:

getVariableDescriptor in interface ValueSelector<Solution_>

Returns:

never null

isCountable

public boolean isCountable()

Description copied from interface: Selector

If false, then Selector.isNeverEnding() is true.

Specified by:

isCountable in interface Selector<Solution_>

Returns:

true if all the ValueRanges are countable (for example a double value range between 1.2 and 1.4 is not countable)

isNeverEnding

public boolean isNeverEnding()

Description copied from interface: Selector

Is true if Selector.isCountable() is false or if this selector is in random order (for most cases). Is never true when this selector is in shuffled order (which is less scalable but more exact).

Specified by:

isNeverEnding in interface Selector<Solution_>

Returns:

true if the Iterator.hasNext() of the Iterator created by Iterable.iterator() never returns false (except when it's empty).

getSize

public long getSize(Object entity)

Description copied from interface: ValueSelector

Similar to IterableSelector.getSize(), but requires an entity.

Specified by:

getSize in interface ValueSelector<Solution_>

Parameters:

entity - never null

Returns:

the approximate number of elements generated by this Selector, always >= 0

getSize

public long getSize()

Description copied from interface: IterableSelector

A random JIT Selector with Selector.isNeverEnding() true should return a size as if it would be able to return each distinct element only once, because the size can be used in SelectionProbabilityWeightFactory.

Specified by:

getSize in interface IterableSelector<Solution_,Object>

Returns:

the approximate number of elements generated by this Selector, always >= 0

iterator

public Iterator<Object> iterator(Object entity)

Description copied from interface: ValueSelector

Similar to Iterable.iterator(), but requires an entity.

Specified by:

iterator in interface ValueSelector<Solution_>

Parameters:

entity - never null

Returns:

never null

iterator

public Iterator<Object> iterator()

Specified by:

iterator in interface Iterable<Solution_>

endingIterator

public Iterator<Object> endingIterator(Object entity)

Description copied from interface: ValueSelector

If Selector.isNeverEnding() is true, then ValueSelector.iterator(Object) will never end. This returns an ending Iterator, that tries to match ValueSelector.iterator(Object) as much as possible, but return each distinct element only once and therefore it might not respect the configuration of this ValueSelector entirely.

Specified by:

endingIterator in interface ValueSelector<Solution_>

Parameters:

entity - never null

Returns:

never null

See Also:

• ValueSelector.iterator(Object)

equals

public boolean equals(Object other)

Specified by:

equals in class AbstractDemandEnabledSelector<Solution_>

hashCode

public int hashCode()

Specified by:

hashCode in class AbstractDemandEnabledSelector<Solution_>