source: fedd/abac-src/ttg/process/RMINegotiator.java @ fc36019

package com.nailabs.abac.process;

import com.nailabs.abac.trust.*;
import com.nailabs.abac.test.*;
import edu.stanford.peer.rbtm.credential.Entity;
import java.rmi.*;
import java.rmi.server.*;

/**
 * This class is a concrete negotiator implementation that employs RMI as the
 * underlying communications transport mechanism.
 */
public class RMINegotiator extends UnicastRemoteObject implements Negotiator  {
    /**
     * The peer with which this instance negotiates.
     */
    protected Negotiator peer;

    /** 
     * The context for the current negotiation, including a trust target graph,
     * strategy, and frontier manager instances.
     */
    protected NegotiationContext context;

    /**
     * Default constructor for the client-side negotiatior. This negotiator
     * is requesting access to a resource.
     */
    public RMINegotiator(NegotiationContext nc) throws RemoteException { 
        context = nc;
    }

    /**
     * Constructor for the server-side negotiator. This negotiator has a 
     * resource that needs protection. 
     */
    public RMINegotiator(TargetNode root, RMINegotiator peer) 
        throws RemoteException {
        setPeer(peer); 
    } 
    
    public Entity getSelf() 
    {
        return context.getSelf();
    }

    /**
     * initial a new root node and start the negotiation process. 
     */
    public boolean negotiate() {
        TTG graph = context.getGraph();
        Strategy s = context.getStrategy();
        SatisfactionState state;
        int i = 0;
        debug("pre-processing locally...");
        //perform strategy once
        s.iterate();
        Message changes = graph.getChanges();
        graph.reset();
        do {
            debug("processing cycle = " + ++i);
            debug("sending message " + changes);
            System.out.println("Sending message: ");
            System.out.println(changes.toXML());
        try {
            Message updates = peer.receive(changes);
            debug("receiving message " + updates);
            changes = receive(updates);
        }
        catch(Exception ex) {
            Debug.rbtmStop();
            ex.printStackTrace();
            return false;
        }
            state = new SatisfactionState(context.getStrategy().getSatisfactionState());
            debug("RMINegotiator:  primary trust target  is " + state);
        }while(state.getState() == SatisfactionState.UNKNOWN && i <= 100);
        // out of the loop so we need to return success or failure
        return (state.getState() == SatisfactionState.SATISFIED);
    }


    /** set the other negotiator dynamically */
    public void setPeer(Negotiator peer) {
        this.peer = peer;
    }

    public void setRoot(TrustTarget tt) {
        context.getGraph().setRoot(tt);
        //TargetNode node = (TargetNode)context.getGraph().getNodeByHash(tt);
        //context.getStrategy().addToWorklist(node);
    }
    

    /** 
     * Synchronously receive a message which can contain multiple operations 
     * from an peer and then return the updates to the originating 
     * peer.
     */
    public Message receive(Message msg) throws Exception {
        Strategy strategy = context.getStrategy();
        TTG graph = context.getGraph();
        Message results = null;

        //for(int i = 0, max = msg.getOperationsCount(); i < max; i++) {
        //    System.out.println("max = " + max);
        //   try {
        //      Operation op = msg.getNextOperation();
        //      op.perform(graph);
        //    }
        //    catch(Exception ex) {
        //      ex.printStackTrace();
        //    }
        //}
        debug("begin receive");
        graph.update(msg);
        debug("graph has been updated");
        strategy.process(msg);
        debug("strategy has processed the work list");
        results = graph.getChanges();
        debug("grabbing the delta list = " + results);
        graph.reset();

        debug("end receive");   
        return results;
    }
    
    /** convenience method for printing messages */
    public void debug(String message) {
        StringBuffer buff = new StringBuffer("RMINegotiator[");
        buff.append(context.getSelf()).append("]: ").append(message);
        //System.out.println(buff);
        Debug.debug("negotiate", buff.toString());
    }
}