source: fedd/abac-src/rbtm/engine/old/ProofNode1.java1 @ df783c1

package edu.stanford.peer.rbtm.engine;

import java.util.*;

import edu.stanford.peer.rbtm.credential.*;
import edu.stanford.peer.rbtm.util.*;

/*
 */
public interface ProofNode extends BackwardSolutionListener, ForwardSolutionListener
{
        EntityExpression getRoleExp();

        void addBackwardListener(BackwardSolutionListener sl);

        /**
         * Process this node for search in the backward direction.  The 
         * implementation of this method should find all nodes that can reach
         * this node directly and do appropriate things.
         */
        void backwardProcess();

        void addForwardListener(ForwardSolutionListener sl);

        void forwardProcess();

        /**
         * add a node as a parent to this node
         * @param  node: the parent node
         */
        void addParent(ProofNode node, Object evidence);

        void addChild(ProofNode node, Object evidence);

        Set getForwardSolutions();

        Set getBackwardSolutions();

        /**
         * Enable this node for backward searching, it then should store all 
         * backward solutions (entities that are member of this node).
         */
        // void enableAllBackwardGoals();

        /**
     * If one only wants to know whether this node has some particular 
         * backward solutions, and doesn't care about others, then one can use 
         * this call to tell this proof node.  It might improve efficiency in 
         * bi-direction search.
         */
    // void enableBackwardGoal(EntityExpression g);

    // void enableAllForwardGoals();
    // void enableForwardGoal(EntityExpression g);      

    // boolean hasParent(ProofNode node);
    // boolean hasChild(ProofNode node);

} // End of class ProofNode