package com.nailabs.abac.credential;

import edu.stanford.peer.rbtm.credential.*;
import edu.stanford.rt.credential.Principal;

/**
 * A hybrid entity instance which is RTML aware but can also emulate a simple
 * entity used by the RBTM package.
 */
public class RtmlEntity implements Entity {
    //The entity will have either a key OR a value but not both
    /** a base-64 encoded hash of the entity's key material */
    protected String hashCode = null;

    /** a short name used in the RTML to refer back to a Principal */
    protected String shortName = null;

    /** constructor for discovery service */
    public RtmlEntity(String shortName) {
	this.shortName = shortName;
    }

    public RtmlEntity(String shortName, String hashCode) {
	this.shortName = shortName;
	this.hashCode = hashCode;
    }

    /** default constructor */
    public RtmlEntity(String shortName, Principal principal) {
        this.shortName = shortName;
        hashCode = principal.toString();
    }

    /** public accessor method for the abbreviated name of an entity */
    public String getName() { return shortName; }

    /** public accessor method for the BASE-64 encoded signature hash */
    public String getHash() { return hashCode; }

    /** public accessor method for the hash code of an entity's key material */
    public int hashCode() { 
	if(hashCode == null) {
	    return shortName.hashCode();
	}
	return hashCode.hashCode(); 
    }

    /** 
     * equivalency should be based on identical hash codes (but potentially
     * short names may be desired).
     */
    public boolean equals(Object o) {
	// warning this is allows an RtmlEntity to be matched by EITHER
	// the hash or the short name. It should probably only be the hash.
	// The RtmlEngine may need to make sure entities have proper hash
	// codes.
	return(o.hashCode()==hashCode() || o.hashCode()==shortName.hashCode());
    }
    
    /** compare to entities based on their unique hash codes */
    public int compareTo(Object obj) {
        return obj.hashCode() - hashCode();
    }

    /** returns the entity's unique hash code as a string */
    public String toString() { return shortName; }

}