source: fedd/abac-src/rbtm/engine/RoleProofNode.java @ 23dec62

package edu.stanford.peer.rbtm.engine;

import java.util.*;

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

/**
 * A proof node which represents a role in the credential graph.
 */
public class RoleProofNode extends AbstractProofNode
{
        /**
         * A map for managing all the partial solutions per intersection that arrive
         */
   static protected PartialSolutionMap partialSolutions = 
                 new PartialSolutionMap();

   /** A forwarlinking monitor which handles linking goals */
        private ForwardLinkingMonitor monitor;

    protected RoleProofNode(ProofGraph graph, Role re, int trackType) {
        super(graph, re, trackType);
    }

    public HashSet getChain(int size, EntityExpression target) {
        if(target.equals(getRoleExp())) {
            System.out.println("\n@@@@@ creating set of size " + size);
            return new HashSet(size);
        }
        System.out.println("\n@@@@@ this = " + getRoleExp());   
        ResultEvidenceMap solutions = getBackwardSolutions();
        //ProofNode nextNode =(ProofNode)solutions.getResultEvidence(target);
        HashSet soln = (HashSet)solutions.getResultEvidence(target);
        System.out.println("solutions = " + solutions);
        System.out.println("soln = " + soln);
        //In the end, there can be only ONE . . . 
        ProofNode nextNode =(ProofNode)soln.iterator().next();
        System.out.println("\n@@@@@ next = " + nextNode.getRoleExp() );
        size++;
        HashSet set = nextNode.getChain(size, target);
        System.out.println("\n@@@@@ children  = " + nextNode.getChildren());
        HashSet results = 
            (HashSet)nextNode.getChildren().getResultEvidence(getRoleExp());
        Iterator evidence = results.iterator();
        while(evidence.hasNext()) {
            set.add((Credential)evidence.next());
        }
        return set;
    }

    public void additionalBackwardProcess() {
        Iterator  credIt = getGraph().findCredentialsDefiningRole((Role)getRoleExp());
        while (credIt.hasNext()) {
            StaticCredential credential = (StaticCredential) credIt.next();
            ProofNode node = getGraph().addBackwardNode(credential.getSubject());
            node.addChild(this, credential);
            //if(addRole)backwardSolutionAdded(this, getRoleExp());
        }
    }

    public void additionalForwardProcess() {
                Role thisRole = (Role)getRoleExp();
                // Make itself a forward solution to itself
                forwardSolutionAdded(this, thisRole);
                
                if (monitor == null) {
                ProofNode node = getGraph().addForwardNode(thisRole.getBase());
                        monitor = new ForwardLinkingMonitor();
                node.addForwardListener(monitor);
                }
    }
         /**
          * Adds a forward solution but propagating the solution backwards along
          * the credential chain. If s is a partial solution and all k pieces have
          * arrived, then add edge from this node to the intersection.
          */
         public void forwardSolutionAdded(ProofNode s, ForwardSolution r) {
                  EntityExpression expr = s.getRoleExp();
                  Iterator iCreds = getGraph().findCredentialsByPartialSubject(expr);
                  
                  super.forwardSolutionAdded(s, r);
                  if(iCreds.hasNext()) {  // if s is partial solution of intersection(s)
                                StaticCredential credential = (StaticCredential) iCreds.next();
                                Intersection i = (Intersection)credential.getSubject();                         
                                if(partialSolutions.addPartialSolution(i, expr)) {
                                         ProofNode node = getGraph().addForwardNode(i);
                                         node.addParent(node, r);
                                }
                  } 
         }

    class ForwardLinkingMonitor implements ForwardSolutionListener {
        public void forwardSolutionAdded(ProofNode s,  ForwardSolution sol) {
                        if (sol instanceof Role) {
                                Role  role = (Role)sol;
                                if (role.getName() instanceof RPermission) {
                                        return;
                                }
                                LinkedRole linkedRole = 
                                         new LinkedRole(role, ((Role)getRoleExp()).getName());
                                //if (getGraph().hasCredentialsForSubject(linkedRole)) {
                                ProofNode node = getGraph().addForwardNode(linkedRole);
                                node.addParent(RoleProofNode.this, s);
                                // addProofEdge(this, node, s);
                        }
        }

            public String toString() {
                return "Monitor " + getRoleExp();
            }
    }
        
        
} // End of class RoleProofNode