package com.nailabs.abac.trust;

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

/**
 * Place holder for sets of nodes. An internal index keeps track of nodes
 * as new ones are added to the set. Future versions may implement a sorting 
 * algorithm for nodes. 
 */
public class TTGNodeSet extends HashMap {
    
    /** index of nodes that have been enqueued for processing */
    protected LinkedList index = new LinkedList();

    /** add a single trust target graph node to the set */
    public boolean add(TTGNode node) {
	boolean isNew = containsValue(node);

	if(node == null) {
	    System.out.println("Attempting to add null node!!");
	    return false;
	}
	if(isNew) {
	    System.out.println("Duplicate node in set. " + node.getGoal());
	    index.add(node);
	} 
	put(node.getGoal(), node);
	return isNew;
    }

    /** adds a set of nodes to the set */
    public boolean addAll(TTGNodeSet set) {
	boolean result = false;
	Iterator i = set.values().iterator();
	while(i.hasNext()) {
	    TTGNode node = (TTGNode)i.next();
	    result = (result || add(node));
	}
	return result;
    }

    public Object getFirst() {
	return index.getFirst();
    }

    public Object getLast() {
	return index.getLast();
    }
}