Restricter.java :  » Testing » KeY » de » uka » ilkd » key » proof » incclosure » Java Open Source

// This file is part of KeY - Integrated Deductive Software Design
// Copyright (C) 2001-2007 Universitaet Karlsruhe, Germany
//                         Universitaet Koblenz-Landau, Germany
//                         Chalmers University of Technology, Sweden
//
// The KeY system is protected by the GNU General Public License. 
// See LICENSE.TXT for details.
//
//

package de.uka.ilkd.key.proof.incclosure;

import de.uka.ilkd.key.logic.Constraint;
import de.uka.ilkd.key.logic.op.Metavariable;
import de.uka.ilkd.key.logic.op.SetAsListOfMetavariable;
import de.uka.ilkd.key.logic.op.SetOfMetavariable;


/**
 * Sink removing given metavariables from passing constraints, thus
 * making variables local
 */
public class Restricter implements Sink {

    /**
     * Variables to remove from passing constraints
     */
    private SetOfMetavariable removedVariables =
  SetAsListOfMetavariable.EMPTY_SET;

    /**
     * Parent sink within the tree of sinks
     */
    private Sink              parent;

    /**
     * PRECONDITION: p_parent != null
     */
    public Restricter ( Sink p_parent ) {
  parent = p_parent;
    }

    /**
     * Add a constraint for which something (a goal or a subtree of
     * the proof) can be closed
     */
    public void       put                ( Constraint p_c ) {
  if ( p_c.isSatisfiable () )
      parent.put ( p_c.removeVariables ( removedVariables ) );
    }

    /**
     * Tell the first restricter (possibly this sink) to remove "p_mv"
     * from any passing constraint
     */
    public void       addRestriction     ( Metavariable p_mv ) {
  removedVariables = removedVariables.add ( p_mv );
    }

    public SetOfMetavariable getRestrictions () {
  return removedVariables;
    }

    /**
     * @return a constraint that restores the current state of this
     * sink and its parents if used with "reset"
     */
    public Constraint getResetConstraint () {
  return parent.getResetConstraint ();
    }

    /**
     * Remove all constraints that have been inserted with "put" until
     * now, replacing them with the only constraint "p_c"
     */
    public void       reset              ( Constraint p_c ) {
  // The set of removed variables is currently not resetted
  parent.reset ( p_c );
    }

    protected Sink    getParent          () {
  return parent;
    }

}