public String getUniqueID() {
    String authority = getAuthority();
    if ((authority != null) && (getID() != null))
      return authority + ":" + getID();
    else if (getID() != null)
      return getID();
    else
      return null;
  }
public String getUniqueID() {
    String authority = getAuthority();
    if ((authority != null) && (getID() != null))
      return authority + ":" + getID();
    else if (getID() != null)
      return getID();
    else
      return null;
  }
public String getUniqueID ( ) { String authority = getAuthority ( ) ; if ( ( authority != null ) && ( getID ( ) != null ) ) return authority + ":" + getID ( ) ; else if ( getID ( ) != null ) return getID ( ) ; else return null ; }
If this dataset has an authority and an ID, then the concatenation of them is the
globally unique ID.

@return globally unique ID, or null if missing authority or ID.
If this dataset has an authority and an ID then the concatenation of them is the globally unique ID .