package com.nailabs.abac.process;

import java.util.*;
import edu.stanford.peer.rbtm.credential.*;
//import edu.stanford.peer.rbtm.engine.StaticCredential;

/**
 * Resource policy for negotiations. The policy can be queried using the 
 * <code>requires</code> method with a specific credential resource 
 * identifier, which can be a URl or a mnemonic identifier.
 */
public class ResourcePolicy implements java.io.Serializable {
    /** Internal hash table for policy storage */
    private HashMap resourcePolicy = null;

    /** Default constructor with a non-resstrictive policy */
    public ResourcePolicy() {
	resourcePolicy = new HashMap();
    }

    /** Accessor for all the access control policy keys */
    public Vector getResourceIdentifiers() { 
        return new Vector(resourcePolicy.keySet()); 
    }

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

    /** Adds a single policy atom from String parameters. */
    public void addResourceFact(String resourceID, String role) 
	throws CredentialParsingException {
	try {
	    addResourceFact(resourceID, (Role)StaticCredential.getRole(role));
	} catch(Exception ex) {
	    ex.printStackTrace();
	}
    }

    /** Adds a single policy atom. */
    public void addResourceFact(String key, Role role) {
	resourcePolicy.put(key, role);
    }

    /** Query the policy to determine the required role for a credential */
    public Role requires(String resource) {
	return (Role)resourcePolicy.get(resource);
    }

    /** Returns the underlying storage data structure in a printable format */
    public String toString() {
	if(resourcePolicy == null)
	    return null;
	else 
	    return resourcePolicy.toString();
    }

}