package com.nailabs.abac.process;

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

/**
 * The acknowledgement policy specifies which opponents can be allowed
 * to receive acknowledgement of credentials possessed by this negotiator.
 */
public class AckPolicy implements edu.stanford.peer.rbtm.RBTMConstants,
				  java.io.Serializable {
    /** The policy data store */
    public HashMap factMap = new HashMap(FACT_MAP_SIZE);
    
    /** Add a fact from the supplied strings */
    public void addAckFact(String base, String roleName, String expr) {
	try {
	    factMap.put(new Role(base, roleName), 
			StaticCredential.getEntityExpression(expr));
	}
	catch(Exception ex) {
	    if(DEBUG)ex.printStackTrace();
	}
    }
    
    /** Add a fact from the supplied object */
    public void addAckFact(EntityExpression role, EntityExpression req) {
	factMap.put(role, new AckFact(role, req));
    }

    /** Return a vector of sensitive roles for the predicate */
    public Vector getSensitiveRoles() {
	return new Vector(factMap.keySet());
    }

    /** 
     * Useful for forward discovery. 
     * @return a set of all roles which satisfy the sensitive requirements
     */
    public Vector getRequiredRoles() {
	return new Vector(factMap.values());
    }

    /** Query policy for the required role to unlock the role expression */
    public EntityExpression requires(EntityExpression key) {
	AckFact fact = (AckFact)factMap.get((Object)key);
	if(fact == null)
	    return null;
	else
	    return (EntityExpression)fact.getRequirement();
    }

    /** Returns the underlying storage data structure in a printable format */
    public String toString() {
	return factMap.toString();
    }

}