package com.nailabs.abac.trust;

import com.nailabs.abac.process.*;
import edu.stanford.peer.rbtm.credential.*;
import java.util.*;

/**
 * An instance of this class represents a linking goal of the form: <BR>
 * <CENTER> &lt;V: ?X.r2 &lt;-- S &gt; </CENTER> <BR>
 * where V is on the negotiators; 
 * r2 is a simple role name; and 
 * ?X represents entities 
 * S is a role expression called the subject role. S is frequently the 
 * opponent negotiator of V.
 */
public class LinkingGoal extends Goal {
    /** The role name suffix (in ?X.r2 this is r2) */
    private RoleName targetRoleName;

    private Entity x = new SimpleEntity("X");

    /** Itemized default constructor */
    public LinkingGoal(Entity v, RoleName e, EntityExpression s) 
        throws TrustTargetParsingException, CredentialParsingException {
        verifier = v;
        targetRoleName = e;
        subject = s;
    }

    /** Construct a new trust target from a string */
    public LinkingGoal(String s) 
        throws TrustTargetParsingException, CredentialParsingException {
        StringTokenizer st = new StringTokenizer(s, ":<-? ");
        try {
            verifier = new SimpleEntity(st.nextToken());
            StringTokenizer rt = new StringTokenizer(st.nextToken(), ".");
            x = new SimpleEntity(rt.nextToken());
            targetRoleName = new SimpleRoleName(rt.nextToken());
            subject = new SimpleEntity(st.nextToken());
        } catch (NoSuchElementException nonesuch) {
            throw new TrustTargetParsingException("Bad linking goal: ", s);
        }

    }

    /** Unique hash function based on a verifier-target-subject triplet */
    public int hashCode() {
        return verifier.hashCode() * 4 + targetRoleName.hashCode() * 2 + 
            subject.hashCode();
    }
    /** processing state for a node repsenting this goal is added to a TTG */ 
    public ProcessingState  getInitialProcessingState(NegotiationContext ctx) {
        // a linking goal is initially verifier-processed */
        return new ProcessingState(true, false); 
    }
    
    /** accessor method for the target role expressin of this target */
    public RoleName getTargetRoleName() { return targetRoleName; }

    /** type name for pretty printing an instance */
    public String getType() {
        return new String("LinkingGoal");
    }

    public String toString() {
	StringBuffer buff = new StringBuffer();
	buff.append(getVerifier().toString()).append(": ");
	buff.append("?").append(x).append(".").append(targetRoleName);
	buff.append(" <<-?- ").append(getSubject().toString());
	return buff.toString();
    }

    public String toXML() {
    /*
	StringBuffer buff = new StringBuffer("<LinkingGoal>\n");
	buff.append("\t<Verifier>");
	buff.append(getVerifier().toString());
	buff.append("</Verifier>\n");
	buff.append("\t<TargetRoleName>");
	buff.append(targetRoleName.toString());
	buff.append("</TargetRoleName>\n");
	buff.append("\t<Subject>");
	buff.append(getSubject().toString());
	buff.append("</Subject>\n");
	buff.append("</TrustTarget>\n");
	return buff.toString();	
    */
        return toString().replaceAll("<", "&lt;");
    }
}