source: fedd/abac-src/ttg/process/StingyStrategy.java @ 16a23a6

package com.nailabs.abac.process;

import edu.stanford.peer.rbtm.credential.*;
import com.nailabs.abac.trust.*;
import com.nailabs.abac.test.*;
import java.util.*;
/**
 * The strategy handles processing a working list of nodes in the trust target
 * graph to be processed. This version uses a combination of heuristics with 
 * a depth first search method.
 */
public class StingyStrategy extends Strategy {
    /** A queue for operations which need to delay */
    protected Hashtable delayedOps = new Hashtable();
    
    /** 
     * A list of sibling children of the current node being processed. Note,
     * this is an ordered stack. Node operations are added the bottom of the
     * stack and implication edges are added to the top. 
     */
    protected Vector siblings = new Vector();

    /** The current node being processed. Null if no local processing. */
    protected TTGNode current = null;
    
    /** Is this strategy currently processing locally? */
    protected boolean isLocal = false;

    /** 
     * A threshold for determining when isDone is high enough 
     */
    public int threshold = 0;

    public float successWeight = 0.0f;

    public CountTable weights = null;

    /** A count of how many criteria have been met for ending a turn */
    protected int isDone = 0;

    /** Check to see if  already saved weights, which should only occur once */
    private boolean isSaved = false;

    /** create a new stingy strategy instance */
    public StingyStrategy(NegotiationContext conf, Properties props) {
        super(conf);
        try {
            if(props.containsKey("successWeight")) {
                successWeight = 
                Float.parseFloat(props.getProperty("successWeight"));
            }
            if(props.containsKey("weightFile")) {
                weights = new CountTable(props.getProperty("weightFile"));
            } else {
                weights = new CountTable("weights." + context.getSelf());
            }
            if(props.containsKey("init")) {
                weights.INIT = 
                    Float.parseFloat(props.getProperty("init"));
            }
            if(props.containsKey("sat")) {
                weights.SAT = 
                    Float.parseFloat(props.getProperty("sat"));
            }
            if(props.containsKey("training")) {
                if(props.getProperty("training").equalsIgnoreCase("true")) {
                    isSaved = false;
                } else {
                    isSaved = true;
                }
            }
        } catch(Exception ex) {
            ex.printStackTrace();
        }
    }

    /**
     * The stingy strategy needs to save weights when the primary trust target
     * is satisfied. This is method tests the predicate and saves the weight
     * states as a side effect.
     */
    public int getSatisfactionState() {
        int state = super.getSatisfactionState();
        if(state == SatisfactionState.UNKNOWN) {
            return state;
        }
        if(isSaved) {
            return state;
        }  
        isSaved = true;
        Iterator i = context.getGraph().getNodes();
        while(i.hasNext()) {
            TTGNode node = (TTGNode)i.next();
            EntityExpression expr = getWeightKey(node.getGoal());
            if(node instanceof TargetNode) {
                state = ((TargetNode)node).getSatisfactionValue();
            } else {
                continue;
            }
            if(state == SatisfactionState.SATISFIED) { // increment success
                weights.addSatisfied(expr);
            } else {
                //if(state == SatisfactionState.FAILED) {    
                //increment failure or unkown nodes
                weights.addFailed(expr);
            }
        }
        debug("strategy", "Saving weights for " + context.getSelf());
        weights.save("weights." + context.getSelf());    
        return state;
    }
    
    /** 
     * Notify the strategy that a new edge needs to be added to the graph.
     * The strategy is responsible for performing the operation on the graph,
     * whether the strategy chooses to  defer the operation or not.
     */
    public void scheduleOperation(Operation op) {
        if(!isLocal) {          // process remote operations directly
            super.scheduleOperation(op);
            return;
        }
        if(op instanceof NodeOperation) { // add node op to end of vector
            siblings.add(op);
        } else if(op instanceof ImplicationEdge) { // add  to front of vector
            //linking implication edges should be performed NOW
            if(op instanceof LinkingImplicationEdge) { 
                super.scheduleOperation(op);
                siblings.remove(op);
            } else {
                siblings.add(0, op);
            }
        } else {                // perform the operation immediately
            super.scheduleOperation(op); 
            siblings.remove(op);
        }
    }

    /** Notify this strategy that a control child has been satisfied */
    public void addSatisfiedControlChild(TTGNode node) {
        Goal g = (Goal)node.getGoal();
        Entity v = g.getVerifier();
        if(!context.getSelf().equals(v)) {
            //weights.addSatisfied(getWeightKey(g));
            isDone++;
        }
    }

    /** Notify this strategy that a new node has been added to the graph */
    public void addNewNode(TTGNode node) {
        if(!isLocal)return;
        ProcessingState state = node.getProcessingState();
        Entity v = node.getGoal().getVerifier();
        if(context.getSelf().equals(v) && state.isVerifierProcessed()) {
            //increment the isDone counter
            isDone++;
        }
        debug("strategy", "node  = " + node.getGoal());
        debug("strategy", "isDone = " + isDone);
    }

    /** iterate through the work list until it is empty */
    public void iterate() {
        isDone = 0;
        while(true) {
            debug("strategy", "beginning iteratiion");
            super.iterate();
            if(okToEndTurn()) {
                debug("strategy", "ending turning now!");
                return;
            }
            debug("strategy", "processing the delayed queue");
            processDelayedOps();
        }
    }

    /** utility function for getting the target expression out of a goal */
    protected EntityExpression getWeightKey(Goal g) {
        EntityExpression key = null;
        if(g instanceof LinkingGoal) {
            String roleName = 
                ((LinkingGoal)g).getTargetRoleName().toString();
            key = new Role("?X", roleName);
        }
        if(g instanceof TrustTarget) {
            key = ((TrustTarget)g).getTargetRole();
        }
        return key;
    }

    /** Note the beginning of a new parent node being processed */
    protected void setCurrentParent(TTGNode parent) {
        //initialize the state variables
        siblings = new Vector();
        current = parent;
        isLocal = true;
        //isDone = 0;
    }

    /** Process all the nodes in the delayed queue */
    protected void processDelayedOps() {
        Iterator i = delayedOps.values().iterator();
        while(i.hasNext()) {
            Vector s = (Vector)i.next();
            while(!s.isEmpty()) {
                debug("strategy", "performing delayed op = " + s.get(0)); 
                super.scheduleOperation((Operation)s.remove(0));
            }
            i.remove();
        }
    }

    /** Note the conclusion of a new parent node being processed */
    protected void scheduleOperationsForNode(TTGNode parent) {
        Entity v = parent.getVerifier();
        int doCount = 0;

        // if self is not parent's verifier, perform all the operations now
        if(!context.getSelf().equals(v)) {
            while(!siblings.isEmpty()) {
                super.scheduleOperation((Operation)siblings.remove(0));
            }
            current = null;
            isLocal = false;
            return;
        }
        // If the verifier finds itself processing a node it has already 
        // processed, it will not add any more operations on that node
        // (this node has been fully processed; therefore, the delayed 
        //  operations can be ignored.)
        if(delayedOps.containsKey(current.getGoal())) {
            debug("strategy", "Already processed node " + current.getGoal());
            debug("strategy", "siblings = " + siblings);
            siblings = new Vector(); // potential memory leak--should be gc'ed
            current = null;
            isLocal = false;
            return;
        }
        //otherwise perform at least one child
        Iterator i = siblings.iterator();
        while(i.hasNext()) {
            Operation op = (Operation)i.next();

            if(op instanceof ImplicationEdge) {
                Goal g = ((EdgeOperation)op).getChild();
                // embedded decision making heuristics
                if(weights.getWeight(getWeightKey(g)) < successWeight) {
                    //do nothing to delay the operation
                    //super.scheduleOperation(op);                     
                } else {
                    super.scheduleOperation(op); 
                    i.remove();
                    doCount += 1;
                }
            }
        }
        // If no edges have been added, take the first implication edge (if
        // any) and perform it.
        i = siblings.iterator();
        while(doCount == 0 && i.hasNext()) { // the while is redundant
            // node operations are processed in the next loop below
            Operation op = (Operation)i.next();
            if(op instanceof ImplicationEdge) {
                super.scheduleOperation(op);
                i.remove();
                doCount += 1;
            }
        }
        //if there are no remaining edge operations, then perform the 
        //remaining node operation (to mark as processed).
        //check for delayed ops and determine whether it's ok to add node op
        if(!siblings.isEmpty()) {
            if(siblings.get(0) instanceof NodeOperation) { 
                // if all edges are done
                NodeOperation nodeOp = (NodeOperation)siblings.remove(0);
                super.scheduleOperation(nodeOp);        
            }
        }
        //put the remaining child edges in the delayed queue
        Goal g = current.getGoal();
        if(!siblings.isEmpty()) {
            delayedOps.put(g, siblings);
        }
        //clean up the state variables
        current = null;
        isLocal = false;
    }

    /** criteria for determining when to end this negotiators turn */
    protected boolean okToEndTurn() {
        // isDone = 0; // used this to check that delayedOps is really empty
        // if there are no more delayed op's, then end this negotiator's turn
        if(delayedOps.isEmpty()) {
            isDone++;          
        }
        //if the negotiation has suceeded or failed, then return true
        if(getSatisfactionState() != SatisfactionState.UNKNOWN) {
            isDone++;
        }
        //if the threshold for end-turn criteria has been met then return true
        if(isDone > threshold) {
            return true;
        }
        // the end-turn criteria have not been met
        return false;
    }

    /** 
     * convenience method for determining whether this negotiator has
     * a deadlock in processing the negotiation. This method can be
     * overridden is subsequent versions.
     */
    protected boolean isStuck() {
        // if there's no history, we cannot be stuck yet
        if(super.isStuck()) {
            if(lastMessage != null) {
                // if both messages contain no changes, 
                //then a deadlock has occurred
                return (lastMessage.getOperationsCount() == 0 );
            }
        }
        return false;
   }



}