ForbiddenArea (JaCoP 4.9.0 API)

java.lang.Object
- org.jacop.constraints.geost.InternalConstraint
- - org.jacop.constraints.geost.ForbiddenArea

```
public class ForbiddenArea
extends InternalConstraint
```
Version:

4.9
The simplest possible internal constraint: DBox defining a set of points with which no object can overlap.

Author:

Marc-Olivier Fleury and Radoslaw Szymanek

Constructor Summary

Constructors
Constructor and Description
`ForbiddenArea(Geost geost, int[] origin, int[] length)` It constructs an internal constraint forbidding an object to be placed within this aread.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`int[]`	`absInfeasible(Geost.SweepDirection minlex)` It provides the largest or smallest point contained in the forbidden area represented by this constraint.
`int`	`cardInfeasible()` It provides an approximation of the number of infeasible points enforced by this constraint only.
`String`	`checkInvariants()` It checks whether the ForbiddenArea is consistent.
`Collection<Var>`	`definingVariables()` It provides a collection, possibly empty, of variables which define this constraint.
`DBox`	`isFeasible(Geost.SweepDirection min, LexicographicalOrder order, GeostObject o, int currentShape, int[] c)` It determines whether the given point is a feasible origin of object o, considering this constraint only.
`boolean`	`isSingleUse()` In some cases, a constraint is used only once per sweep direction on a path from root to leaf in the search tree.
`boolean`	`isStatic()` It provides information about the constraint future.

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

- Constructor Detail
  - ForbiddenArea
```
public ForbiddenArea(Geost geost,
                     int[] origin,
                     int[] length)
```
    It constructs an internal constraint forbidding an object to be placed within this aread.
    
    Parameters:
    
    geost - the geost constraint in which this internal constraint exists.
    
    origin - the origin of the forbidden area.
    
    length - the length of the forbidden area.
- Method Detail
  - checkInvariants
```
public String checkInvariants()
```
    It checks whether the ForbiddenArea is consistent.
    
    Returns:
    
    It returns the string description of the problem, or null if no problem with data structure consistency encountered.
  - isFeasible
```
public DBox isFeasible(Geost.SweepDirection min,
                       LexicographicalOrder order,
                       GeostObject o,
                       int currentShape,
                       int[] c)
```
    Description copied from class: InternalConstraint
    
    It determines whether the given point is a feasible origin of object o, considering this constraint only. If it is not, returns a DBox corresponding to the largest infeasible domain, considering a sweep which uses the given ordering.
    The boundaries of the forbidden area must have the following properties: the lower extremum has to be infeasible, but the upper extremum has to be feasible (with respect to this constraint only).
    The dimension of the DBox returned is k+1, where k is the object dimension. The last dimension is time.
    
    Specified by:
    
    isFeasible in class InternalConstraint
    
    Parameters:
    
    min - the direction of the sweep
    
    order - the order to be used
    
    o - the object the constraint is applied to
    
    currentShape - the shape id that is currently considered for o
    
    c - the current position of the sweep.
    
    Returns:
    
    a DBox representing the forbidden region
  - absInfeasible
```
public int[] absInfeasible(Geost.SweepDirection minlex)
```
    Description copied from class: InternalConstraint
    
    It provides the largest or smallest point contained in the forbidden area represented by this constraint. This point must be larger or equal (resp. smaller or equal) to the lexicographically largest (resp. smallest) point included in the forbidden area, whatever the lexical order is.
    TODO, is this function potentially still useful? If not remove, if yes then adapt the description about event point series. What is it used now for? I will keep it as it may be used later on, but for sure the code implementing those functions is not tested much or requires some cleaning.
    This allows to build an event point series that stays consistent whatever the lexical order is, and whatever the object to place is (some shifting is applied to take the object's shape into account)
    The dimension of the point returned is k+1, where k is the object dimension. The last dimension is time.
    
    Specified by:
    
    absInfeasible in class InternalConstraint
    
    Parameters:
    
    minlex - defines whether the maximal or minimal point should be returned
    
    Returns:
    
    the infeasible point's coordinates. If constraint cannot generate outbox then it returns null.
  - cardInfeasible
```
public final int cardInfeasible()
```
    Description copied from class: InternalConstraint
    
    It provides an approximation of the number of infeasible points enforced by this constraint only. The information provided by this function cannot be accurate, since no object is passed as an argument, but some consistent approximation should exist. For instance, in the case of a forbidden area, the returned value can be the number of points included in the area.
    This information is used as a heuristic in the sweeping algorithm to decide which constraint to use, so that the constraints that cover the largest space are used first.
    
    Specified by:
    
    cardInfeasible in class InternalConstraint
    
    Returns:
    
    an approximation of the number of infeasible points enforced by this constraint only.
  - definingVariables
```
public Collection<Var> definingVariables()
```
    Description copied from class: InternalConstraint
    
    It provides a collection, possibly empty, of variables which define this constraint. This information is used to build a reverse index that allows to update the absolute infeasible points of a constraint when a variable changes.
    
    Specified by:
    
    definingVariables in class InternalConstraint
    
    Returns:
    
    the collection containing variables that define that constraint.
  - isStatic
```
public boolean isStatic()
```
    Description copied from class: InternalConstraint
    
    It provides information about the constraint future. If a constraint will always generate the same outboxes deeper in the tree, it should return false, so that jumps in the event point series can be done.
    TODO the description above suggests that it should be called isDynamic as it returns false if the constraint outboxes stay the same.
    (not taking placed object into account; i.e. absInfeasible will always return the same points)
    
    Specified by:
    
    isStatic in class InternalConstraint
    
    Returns:
    
    TODO, proper description after fixing the above todo.
  - isSingleUse
```
public boolean isSingleUse()
```
    Description copied from class: InternalConstraint
    
    In some cases, a constraint is used only once per sweep direction on a path from root to leaf in the search tree. In that case, the constraint can be ignored if it was seen at some point.
    TODO, what is the example of such constraint?
    Use this function to provide the information to Geost.
    
    Specified by:
    
    isSingleUse in class InternalConstraint
    
    Returns:
    
    TODO. Is this function used at all? It seems that all implementations return false and nowhere in geost it is used.

Class ForbiddenArea

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Constructor Detail

ForbiddenArea

Method Detail

checkInvariants

isFeasible

absInfeasible

cardInfeasible

definingVariables

isStatic

isSingleUse