question: public static AclScope fromExternalForm ( String externalForm ) { if ( externalForm == null ) { return null ; } if ( externalForm . equals ( getTypeIdentifier ( Type . DEFAULT ) ) ) { return new AclScope ( Type . DEFAULT , null ) ; } String [ ] components = externalForm . split ( ":" ) ; if ( components . length != 2 ) { return null ; } Type type = getType ( components [ 0 ] ) ; if ( type == null || type == Type . DEFAULT ) { return null ; } return new AclScope ( type , components [ 1 ] ) ; }
target:  Given a standard external representation, return the scope that it represents or null if an invalid representation.  This is the inverse operation of toExternalForm.