ExtensionalSupportVA (jacop 4.2.0 API)

java.lang.Object
- org.jacop.constraints.DecomposedConstraint
- - org.jacop.constraints.Constraint
  - - org.jacop.constraints.ExtensionalSupportVA

```
public class ExtensionalSupportVA
extends Constraint
```
Extensional constraint assures that one of the tuples is enforced in the relation. This implementation tries to balance the usage of memory versus time efficiency.

Version:

4.2

Author:

Radoslaw Szymanek

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`idNumber` It specifies the id of the constraint.
`IntVar[]`	`list` It stores variables within this extensional constraint, order does matter.
`static String[]`	`xmlAttributes` It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.

Fields inherited from class org.jacop.constraints.Constraint
atomicExecution, consistencyPruningEvents, earlyTerminationOK, id, increaseWeight, numberArgs, numberId, trace

Fields inherited from class org.jacop.constraints.DecomposedConstraint
queueIndex

Constructor Summary

Constructors
Constructor and Description
`ExtensionalSupportVA(ArrayList<? extends IntVar> variables, int[][] tuples)` The constructor does not create local copy of tuples array.
`ExtensionalSupportVA(IntVar[] list)` Partial constructor which stores variables involved in a constraint but does not get information about tuples yet.
`ExtensionalSupportVA(IntVar[] variables, int[][] tuples)` Constructor stores reference to tuples until imposition, any changes to tuples parameter will be reflected in the constraint behavior.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`ArrayList<Var>`	`arguments()` It returns the variables in a scope of the constraint.
`void`	`consistency(Store store)` It is a (most probably incomplete) consistency function which removes the values from variables domains.
`int[]`	`findFirstAllowed(int varPosition, int value, int[] t)` It finds the first allowed tuple from the given tuple.
`protected int`	`findPosition(int value, int[] values)`
`static void`	`fromXML(ExtensionalSupportVA object, String content)` It updates the specified constraint with the information stored in the string.
`int`	`getConsistencyPruningEvent(Var var)` It retrieves the pruning event which causes reevaluation of the constraint.
`void`	`impose(Store store)` It imposes the constraint in a given store.
`void`	`increaseWeight()` It increases the weight of the variables in the constraint scope.
`void`	`queueVariable(int level, Var var)` This is a function called to indicate which variable in a scope of constraint has changed.
`void`	`removeConstraint()` It removes the constraint by removing this constraint from all variables.
`void`	`removeLevel(int level)` It puts back tuples which have lost their support status at the level which is being removed.
`boolean`	`satisfied()` It checks if the constraint is satisfied.
`int`	`seekInvalidPosition(int[] t)` It gives the position of the variable for which current domain of this variable does not hold the used value.
`int[]`	`seekSupportVA(int varPosition, int value)` It seeks support for a given variable-value pair.
`int[]`	`setFirstValid(int varPosition, int value)` It computes the first valid tuple for a given variable-value pair.
`String`	`toString()` It produces a string representation of a constraint state.
`void`	`toXML(TransformerHandler tf)` It writes the content of this object as the content of XML element so later it can be used to restore the object from XML.

Methods inherited from class org.jacop.constraints.Constraint
cleanAfterFailure, decompose, getGuideConstraint, getGuideValue, getGuideVariable, id, impose, imposeDecomposition, numberArgs, removeLevelLate, requiresMonotonicity, setConsistencyPruningEvent, supplyGuideFeedback

Methods inherited from class org.jacop.constraints.DecomposedConstraint
auxiliaryVariables, derivative, imposeDecomposition

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - idNumber
```
public static int idNumber
```
    It specifies the id of the constraint.
  - list
```
public IntVar[] list
```
    It stores variables within this extensional constraint, order does matter.
  - xmlAttributes
```
public static String[] xmlAttributes
```
    It specifies the arguments required to be saved by an XML format as well as the constructor being called to recreate an object from an XML format.
- Constructor Detail
  - ExtensionalSupportVA
```
public ExtensionalSupportVA(IntVar[] list)
```
    Partial constructor which stores variables involved in a constraint but does not get information about tuples yet. The tuples must set separately.
    
    Parameters:
    
    list -
  - ExtensionalSupportVA
```
public ExtensionalSupportVA(ArrayList<? extends IntVar> variables,
                            int[][] tuples)
```
    The constructor does not create local copy of tuples array. Any changes to this array will reflect on constraint behavior. Most probably incorrect as other data structures will not change accordingly.
    
    Parameters:
    
    variables - the constraint scope.
    
    tuples - the tuples which are supports for the constraint.
  - ExtensionalSupportVA
```
public ExtensionalSupportVA(IntVar[] variables,
                            int[][] tuples)
```
    Constructor stores reference to tuples until imposition, any changes to tuples parameter will be reflected in the constraint behavior. Changes to tuples should not performed under any circumstances. The tuples array is not copied to save memory and time.
    
    Parameters:
    
    variables - the constraint scope.
    
    tuples - the tuples which are supports for the constraint.
- Method Detail
  - seekSupportVA
```
public int[] seekSupportVA(int varPosition,
                           int value)
```
    It seeks support for a given variable-value pair.
    
    Parameters:
    
    varPosition - position of the variable for which the support is seek.
    
    value - value for which the support is seek.
    
    Returns:
    
    support tuple.
  - setFirstValid
```
public int[] setFirstValid(int varPosition,
                           int value)
```
    It computes the first valid tuple for a given variable-value pair.
    
    Parameters:
    
    varPosition - position of the variable.
    
    value - value for which the fist valid tuple is seek.
    
    Returns:
    
    first valid tuple.
  - findFirstAllowed
```
public int[] findFirstAllowed(int varPosition,
                              int value,
                              int[] t)
```
    It finds the first allowed tuple from the given tuple.
    
    Parameters:
    
    varPosition - position of the variable.
    
    value - value for which first allowed tuple is seek.
    
    t - tuple from which the search commences.
    
    Returns:
    
    first allowed tuple for a given variable-value pair.
  - seekInvalidPosition
```
public int seekInvalidPosition(int[] t)
```
    It gives the position of the variable for which current domain of this variable does not hold the used value. It is variable because of which allowed tuple does not become a support tuple.
    
    Parameters:
    
    t - tuple being checked.
    
    Returns:
    
    -1 if tuple is both valid and allowed (support), otherwise the position.
  - arguments
```
public ArrayList<Var> arguments()
```
    Description copied from class: Constraint
    
    It returns the variables in a scope of the constraint.
    
    Specified by:
    
    arguments in class Constraint
    
    Returns:
    
    variables in a scope of the constraint.
  - removeLevel
```
public void removeLevel(int level)
```
    It puts back tuples which have lost their support status at the level which is being removed.
    
    Overrides:
    
    removeLevel in class Constraint
    
    Parameters:
    
    level - the level which is being removed.
  - consistency
```
public void consistency(Store store)
```
    Description copied from class: Constraint
    
    It is a (most probably incomplete) consistency function which removes the values from variables domains. Only values which do not have any support in a solution space are removed.
    
    Specified by:
    
    consistency in class Constraint
    
    Parameters:
    
    store - constraint store within which the constraint consistency is being checked.
  - findPosition
```
protected int findPosition(int value,
                           int[] values)
```
  - getConsistencyPruningEvent
```
public int getConsistencyPruningEvent(Var var)
```
    Description copied from class: Constraint
    
    It retrieves the pruning event which causes reevaluation of the constraint.
    
    Specified by:
    
    getConsistencyPruningEvent in class Constraint
    
    Parameters:
    
    var - variable for which pruning event is retrieved
    
    Returns:
    
    it returns the int code of the pruning event (GROUND, BOUND, ANY, NONE)
  - impose
```
public void impose(Store store)
```
    Description copied from class: Constraint
    
    It imposes the constraint in a given store.
    
    Specified by:
    
    impose in class Constraint
    
    Parameters:
    
    store - the constraint store to which the constraint is imposed to.
  - queueVariable
```
public void queueVariable(int level,
                          Var var)
```
    Description copied from class: Constraint
    
    This is a function called to indicate which variable in a scope of constraint has changed. It also indicates a store level at which the change has occurred.
    
    Overrides:
    
    queueVariable in class Constraint
    
    Parameters:
    
    level - the level of the store at which the change has occurred.
    
    var - variable which has changed.
  - removeConstraint
```
public void removeConstraint()
```
    Description copied from class: Constraint
    
    It removes the constraint by removing this constraint from all variables.
    
    Specified by:
    
    removeConstraint in class Constraint
  - satisfied
```
public boolean satisfied()
```
    Description copied from class: Constraint
    
    It checks if the constraint is satisfied. If this function is incorrectly implemented a constraint may not be satisfied in a solution.
    
    Specified by:
    
    satisfied in class Constraint
    
    Returns:
    
    true if the constraint is for certain satisfied, false otherwise.
  - toString
```
public String toString()
```
    Description copied from class: Constraint
    
    It produces a string representation of a constraint state.
    
    Specified by:
    
    toString in class Constraint
  - toXML
```
public void toXML(TransformerHandler tf)
           throws SAXException
```
    It writes the content of this object as the content of XML element so later it can be used to restore the object from XML. It is done after restoration of the part of the object specified in xmlAttributes.
    
    Parameters:
    
    tf - a place to write the content of the object.
    
    Throws:
    
    SAXException
  - fromXML
```
public static void fromXML(ExtensionalSupportVA object,
                           String content)
```
    It updates the specified constraint with the information stored in the string.
    
    Parameters:
    
    object - the constraint to be updated.
    
    content - the information used for update.
  - increaseWeight
```
public void increaseWeight()
```
    Description copied from class: Constraint
    
    It increases the weight of the variables in the constraint scope.
    
    Specified by:
    
    increaseWeight in class Constraint

Class ExtensionalSupportVA

Field Summary

Fields inherited from class org.jacop.constraints.Constraint

Fields inherited from class org.jacop.constraints.DecomposedConstraint

Constructor Summary

Method Summary

Methods inherited from class org.jacop.constraints.Constraint

Methods inherited from class org.jacop.constraints.DecomposedConstraint

Methods inherited from class java.lang.Object

Field Detail

idNumber

list

xmlAttributes

Constructor Detail

ExtensionalSupportVA

ExtensionalSupportVA

ExtensionalSupportVA

Method Detail

seekSupportVA

setFirstValid

findFirstAllowed

seekInvalidPosition

arguments

removeLevel

consistency

findPosition

getConsistencyPruningEvent

impose

queueVariable

removeConstraint

satisfied

toString

toXML

fromXML

increaseWeight