NotEqualConstraint.java

/**
  * This program (working title: MAS Prover) is an automated tableaux prover
  * for epistemic logic (S5n).
  * Copyright (C) 2007  Elske van der Vaart and Gert van Valkenhoef

  * This program is free software; you can redistribute it and/or modify it
  * under the terms of the GNU General Public License version 2 as published
  * by the Free Software Foundation.

  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.

  * You should have received a copy of the GNU General Public License along
  * with this program; if not, write to the Free Software Foundation, Inc.,
  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */

package nl.rug.ai.mas.oops.tableau;

import nl.rug.ai.mas.oops.formula.*;

public class NotEqualConstraint implements Constraint {
	private Variable<Agent> d_a1;
	private Variable<Agent> d_a2;

	public NotEqualConstraint(Variable<Agent> a1, Variable<Agent> a2) {
		d_a1 = a1;
		d_a2 = a2;
	}

	public boolean validate(NodeSubstitution s) {
		if (s.getAgentSubstitution().get(d_a1).equals(
					s.getAgentSubstitution().get(d_a2)))
			return false;
		return true;
	}

	public String toString() {
		return "CONSTRAINT(" + d_a1 + " != " + d_a2 + ")";
	}
}