jpaul.Constraints.SetConstraints
Class IntersectConstraint<T>

java.lang.Object
  jpaul.Constraints.Constraint<SVar<T>,java.util.Set<T>>
      jpaul.Constraints.SetConstraints.IntersectConstraint<T>

public class IntersectConstraint<T>
extends Constraint<SVar<T>,java.util.Set<T>>

IntersectConstraint models a set intersection constraint. Mathematically, such a constraint has the form:

vIn1 /\ vIn2 <= vDest

where /\ stands for set intersection, <= stands for set inclusion, and vIn1, vIn2, vDest are set-valued variables.

Version:

$Id: IntersectConstraint.java,v 1.6 2006/03/14 02:29:30 salcianu Exp $

Author:

Alexandru Salcianu - salcianu@alum.mit.edu

Field Summary

Fields inherited from class jpaul.Constraints.Constraint

AVG_COST, HIGH_COST, LOW_COST, VERY_LOW_COST

Constructor Summary

IntersectConstraint(SVar<T> vIn1, SVar<T> vIn2, SVar<T> vDest)
Creates a IntersectConstraint with the meaning vIn1 /\ vIn2 <= vDest.

Method Summary

void	action(SolAccessor<SVar<T>,java.util.Set<T>> sa) Performs the action attached to this constraint.
int	cost() Returns HIGH_COST.
boolean	equals(java.lang.Object o)
int	hashCode()
java.util.Collection<SVar<T>>	in()
java.util.Collection<SVar<T>>	out()
Constraint<SVar<T>,java.util.Set<T>>	rewrite(UnionFind<SVar<T>> uf) We implemented rewrite(jpaul.DataStructs.UnionFind>), equals(java.lang.Object), and hashCode, such that constraints that are identical after variable unification are not duplicated needlessly.
java.lang.String	toString()

Methods inherited from class java.lang.Object

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

Constructor Detail

IntersectConstraint

public IntersectConstraint(SVar<T> vIn1,
                           SVar<T> vIn2,
                           SVar<T> vDest)

Creates a IntersectConstraint with the meaning vIn1 /\ vIn2 <= vDest.

Method Detail

in

public java.util.Collection<SVar<T>> in()

Specified by:

in in class Constraint<SVar<T>,java.util.Set<T>>

Returns:

List of variables whose values may be read in order to construct the values of the outputs.

out

public java.util.Collection<SVar<T>> out()

Specified by:

out in class Constraint<SVar<T>,java.util.Set<T>>

Returns:

List of variables whose values may be affected by this constraint.

cost

public int cost()

Returns HIGH_COST.

Overrides:

cost in class Constraint<SVar<T>,java.util.Set<T>>

action

public void action(SolAccessor<SVar<T>,java.util.Set<T>> sa)

Description copied from class: Constraint

Performs the action attached to this constraint. The action should have the following form:

1. Read the values of several in-variables using sa.get.
2. Compute some values.
3. Use sa.join to join the computed values to several out-variables.

Note1: It is a serious mistake to write an action method that reads/modifies variables that are not listed in the collections returned by in()/out(). If you ever suspect such an error, please set ConstraintSystem.CHECK_IN_OUT to true.

Note2: The solver initializes each variable to null (null is considered equivalent to the bottom element of the correspoding lattice). The body of action should be prepared to receive a null result from sa.get.

Specified by:

action in class Constraint<SVar<T>,java.util.Set<T>>

Parameters:

sa - Provides access to the values of the variables that are read/modified.

rewrite

public Constraint<SVar<T>,java.util.Set<T>> rewrite(UnionFind<SVar<T>> uf)

We implemented rewrite(jpaul.DataStructs.UnionFind>), equals(java.lang.Object), and hashCode, such that constraints that are identical after variable unification are not duplicated needlessly.

Overrides:

rewrite in class Constraint<SVar<T>,java.util.Set<T>>

Parameters:

uf - Union-find structure; for each variable v, uf.find(v) is the representative of its equivalence class.

equals

public boolean equals(java.lang.Object o)

Overrides:

equals in class java.lang.Object

hashCode

public int hashCode()

Overrides:

hashCode in class java.lang.Object

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object