create or replace type force_sensitive force as object 
( 
  -- First we define object-level attributes 
  c_name varchar2(100), 
  -- notice the comma instead of semicolon: 
  -- this is a definition, similar to table definition - not 
  -- an implemenntation. 
 
  -- define a function we are going to implement 
  member function name 
    return varchar2, 
 
  -- and one we are only going to implement 
  -- inside the children 
  not instantiable member function alignment 
    return varchar2 
) 
-- For this is our base type we dont want it to be 
-- instantiable, e.g. no "new force_sensitive()" possible 
not final not instantiable; 

create or replace type body force_sensitive as 
  member function name 
    return varchar2 
  as 
    begin 
      return c_name; 
    end; 
end; 

create or replace type jedi under force_sensitive ( 
  overriding member function alignment 
    return varchar2 
); 

create or replace type body jedi as 
  overriding member function alignment 
    return varchar2 
  as 
    begin 
      return 'light'; 
    end; 
end; 

create or replace type sith under force_sensitive ( 
  -- Default constructor has all member-attributes 
  -- as parameters and assignes them. We can change 
  -- this with our own constructor 
  constructor function sith( c_name in varchar2 ) 
    return self as result, 
 
  overriding member function alignment 
    return varchar2 
); 

create or replace type body sith as 
  constructor function sith( c_name in varchar2 ) 
    return self as result 
  is 
    begin 
      -- self is a special built-in parameter 
      -- which is passed to each member function as first 
      -- parameter, no matter if explicitly defined or not. 
      -- It holds an instance to the object 
      self.c_name := 'Darth ' || c_name; 
 
      -- however, in a constructor we dont return self 
      -- but just return. 
      return; 
    end; 
 
  overriding member function alignment 
    return varchar2 is 
    begin 
      return 'dark'; 
    end; 
end; 

declare 
  l_luke force_sensitive; 
  l_vader force_sensitive; 
 
  -- We can here see one of the first gifts of plsql- 
  -- objects: We can build generalized methods which 
  -- work for any subtype 
  procedure output_alignment( 
    i_force_user in out nocopy force_sensitive ) 
  as 
    begin 
      dbms_output.put_line(i_force_user.name() || 
        ' is aligned to ' || i_force_user.alignment()); 
    end; 
begin 
  -- Create a new instance of a concrete type 
  l_luke := new jedi('Luke Skywalker'); 
  output_alignment(l_luke); 
 
  l_vader := new sith('Vader'); 
  output_alignment(l_vader); 
end;