/**
* Copyright (c) 1999-2014, Ecole des Mines de Nantes
* All rights reserved.
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* modification, are permitted provided that the following conditions are met:
*
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* documentation and/or other materials provided with the distribution.
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* names of its contributors may be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND ANY
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package solver.constraints.reification;
import gnu.trove.map.hash.THashMap;
import solver.Solver;
import solver.constraints.Constraint;
import solver.constraints.Propagator;
import solver.constraints.PropagatorPriority;
import solver.exception.ContradictionException;
import solver.exception.SolverException;
import solver.variables.Variable;
import util.ESat;
/**
* Constraint representing the negation of a given constraint
* does not filter but fails if the given constraint is satisfied
* Can be used within any constraint
* <p/>
* Should not be called by the user
*
* @author Jean-Guillaume Fages
* @since 15/05/2013
*/
public class PropOpposite extends Propagator {
// constraint to negate
Constraint original;
public PropOpposite(Constraint original, Variable[] vars) {
super(vars, PropagatorPriority.LINEAR, false);
this.original = original;
}
@Override
public void propagate(int evtmask) throws ContradictionException {
ESat op = original.isSatisfied();
if (op == ESat.TRUE) {
contradiction(vars[0], "");
}
if (op == ESat.FALSE) {
setPassive();
}
}
@Override
public ESat isEntailed() {
ESat op = original.isSatisfied();
if (op == ESat.TRUE) {
return ESat.FALSE;
}
if (op == ESat.FALSE) {
return ESat.TRUE;
}
return ESat.UNDEFINED;
}
@Override
public void duplicate(Solver solver, THashMap identitymap) {
throw new SolverException("PropOpposite cannot be duplicated!");
}
}