org.drools.planner.api.domain.variable
Annotation Type PlanningVariable

@Target(value=METHOD)
@Retention(value=RUNTIME)
public @interface PlanningVariable

Specifies that a bean property should be optimized by Drools Planner.

It is specified on a getter of a java bean property of a PlanningEntity class.

Optional Element Summary

boolean	chained In some use cases, such as Vehicle Routing, planning entities are chained.
Class<? extends PlanningVariableListener>[]	listenerClasses Deprecated.
boolean	nullable A nullable planning variable will automatically add the planning value null to the ValueRange.
Class<? extends Comparator>	strengthComparatorClass Allows a collection of planning values for this variable to be sorted by strength.
Class<? extends PlanningValueStrengthWeightFactory>	strengthWeightFactoryClass Allows a collection of planning values for this variable to be sorted by strength.
Class<? extends SelectionFilter>	uninitializedEntityFilter Construction heuristics only change (effectively reset) uninitialized planning variables.

nullable

public abstract boolean nullable

A nullable planning variable will automatically add the planning value null to the ValueRange.

In repeated planning use cases, it's recommended to specify a uninitializedEntityFilter() for every nullable planning variable too.

nullable() true is not compatible with {#link #chained} true. nullable() true is not compatible with a primitive property type.

Returns:

true if null is a valid value for this planning variable

Default:

false

uninitializedEntityFilter

public abstract Class<? extends SelectionFilter> uninitializedEntityFilter

Construction heuristics only change (effectively reset) uninitialized planning variables. An initialized planning variable is ignored by construction heuristics. This is especially useful in repeated planning use cases, in which starting from scratch would waste previous results and time.

If no uninitializedEntityFilter() is specified, the default considers an entity uninitialized for a variable if its value is null.

The method SelectionFilter.accept(ScoreDirector, Object) returns false if the selection entity is initialized for this variable and it returns true if the selection entity is uninitialized for this variable

Returns:

PlanningVariable.NullUninitializedEntityFilter when it is null (workaround for annotation limitation)

Default:

org.drools.planner.api.domain.variable.PlanningVariable.NullUninitializedEntityFilter.class

strengthComparatorClass

public abstract Class<? extends Comparator> strengthComparatorClass

Allows a collection of planning values for this variable to be sorted by strength.

Do not use together with strengthWeightFactoryClass().

Returns:

PlanningVariable.NullStrengthComparator when it is null (workaround for annotation limitation)

Default:

org.drools.planner.api.domain.variable.PlanningVariable.NullStrengthComparator.class

strengthWeightFactoryClass

public abstract Class<? extends PlanningValueStrengthWeightFactory> strengthWeightFactoryClass

Allows a collection of planning values for this variable to be sorted by strength.

Do not use together with strengthComparatorClass().

Returns:

PlanningVariable.NullStrengthWeightFactory when it is null (workaround for annotation limitation)

See Also:

PlanningValueStrengthWeightFactory

Default:

org.drools.planner.api.domain.variable.PlanningVariable.NullStrengthWeightFactory.class

chained

public abstract boolean chained

In some use cases, such as Vehicle Routing, planning entities are chained. A chained variable recursively points to a planning fact, which is called the anchor. So either it points directly to the anchor (that planning fact) or it points to another planning entity with the same planning variable (which recursively points to the anchor). Chains always have exactly 1 anchor, thus they never loop and the tail is always open. Chains never split into a tree: a anchor or planning entity has at most 1 trailing planning entity.

When a chained planning entity changes position, then chain correction must happen:

• divert the chain link at the new position to go through the modified planning entity
• close the missing chain link at the old position

For example: Given A <- B <- C <- D <- X <- Y, when B moves between X and Y, pointing to X, then Y is also changed to point to B and C is also changed to point to A, giving the result A <- C <- D <- X <- B <- Y.

nullable() true is not compatible with {#link #chained} true.

Returns:

true if changes to this variable need to trigger chain correction

Default:

false

listenerClasses

@Deprecated
public abstract Class<? extends PlanningVariableListener>[] listenerClasses

Deprecated.

Default:

{}