package edu.stanford.peer.rbtm.engine;

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

import java.util.*;

/**
 * A predicate for determining whether a credential is sensitive.
 */
public class Sens implements Predicate {

    /** A list of sensitive credentials for this predicate */
    protected Vector sens;

    /**
     * Create a new sens predicate with no sensitive credentials.
     */
    public Sens() { sens = new Vector(); }

    /**
     * Create a new sens predicate with a list of pre-defined sensitive 
     * credentials.
     */
    public Sens(Vector creds) { 
	sens = new Vector();
	for(int i = 0; i < creds.size(); i++) {
	    try {
		Role r = (Role)creds.elementAt(i);
		sens.addElement(r);
	    }
	    catch(Exception ex) {
		ex.printStackTrace();
	    }
	}
    }

    /** Mark a credential as sensitive w/o exposing internal data structures */
    public void addSensCred(Role role) { sens.add(role); }

    /** Remove a credential from the sensitive list (opaquely) */
    public void removeSensCred(Role role) { sens.remove(role); }

    /** 
     * Predicate function to test whether the supplied role expression is 
     * sensitive or not. The obj must be a credential for the test to succeed.
     *
     * @param obj a credential instance for the predicate to test
     * @return success of failure of the predicate
     */
    public boolean test(EntityExpression obj) {
	if(!(obj instanceof Role))return true;
	Role role = (Role)obj;
	return (sens.contains(role));
	/*
	if(!sens.contains(role)) {
	    return false;
	}
	return true;
	*/
    }
    
}