package com.nailabs.abac.trust;

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

/**
 * An interface for representing either a trust target or linking goal. Both
 * subclasses contain a verifier and subject. Target expressions are extended
 * uniquely.
 */
public abstract class  Goal implements java.io.Serializable {
    /** The verifier of this trust target */
    protected Entity verifier;

    /** The subject expression of this trust target */
    protected EntityExpression subject;

    /** accessor method for the subject of this trust target */
    public EntityExpression getSubject() { return subject; }

    /** accessor method for the verifier of this target */
    public Entity getVerifier() { return verifier; }

    /** processing state for a node repsenting this goal is added to a TTG */ 
    public abstract ProcessingState getInitialProcessingState(NegotiationContext ctx);

    /** convert this goal into an XML formatted string */
    public abstract String toXML();

    /** a string representing the type of the goal */
    public abstract String getType();
}