Package org.optaplanner.core.api.domain.variable

Annotation Type ShadowVariable

@Target({METHOD,FIELD})
@Retention(RUNTIME)
@Repeatable(List.class)
public @interface ShadowVariable

Specifies that a bean property (or a field) is a custom shadow variable of 1 or more source variables. The source variable may be a genuine PlanningVariable, PlanningListVariable, or another shadow variable.

It is specified on a getter of a java bean property (or a field) of a PlanningEntity class.

Required Element Summary

Required Elements

Modifier and Type	Required Element	Description
String	sourceVariableName	The source variable name.
Class<? extends AbstractVariableListener>	variableListenerClass	A VariableListener or ListVariableListener gets notified after a source planning variable has changed.

Optional Element Summary

Optional Elements

Modifier and Type	Optional Element	Description
Class<?>	sourceEntityClass	The PlanningEntity class of the source variable.

Element Detail

variableListenerClass

Class<? extends AbstractVariableListener> variableListenerClass

A VariableListener or ListVariableListener gets notified after a source planning variable has changed. That listener changes the shadow variable (often recursively on multiple planning entities) accordingly. Those shadow variables should make the score calculation more natural to write.

For example: VRP with time windows uses a VariableListener to update the arrival times of all the trailing entities when an entity is changed.

Returns:

a variable listener class

sourceVariableName

String sourceVariableName

The source variable name.

Returns:

never null, a genuine or shadow variable name

sourceEntityClass

Class<?> sourceEntityClass

The PlanningEntity class of the source variable.

Specified if the source variable is on a different Class than the class that uses this referencing annotation.

Returns:

ShadowVariable.NullEntityClass when the attribute is omitted (workaround for annotation limitation). Defaults to the same Class as the one that uses this annotation.

Default:

org.optaplanner.core.api.domain.variable.ShadowVariable.NullEntityClass.class