@Override
    public int hashCode()
    {
        int result = rosterItems.hashCode();
        result = 31 * result + implicitFrom.hashCode();
        result = 31 * result + username.hashCode();
        return result;
    }
Generates a hash code based on only those fields that are relevant for Roster Versioning (as defined in RFC 6121 section 2.6).

@return A hash code
xmppserver/src/main/java/org/jivesoftware/openfire/roster/Roster.java