Delphi Singleton Pattern [closed]

Answer 1

There is a way to hide the inherited “Create” constructor of TObject. Although it is not possible to change the access level, it can be hidden with another public parameterless method with the same name: “Create”. This simplifies the implementation of the Singleton class tremendously. See the simplicity of the code:

unit Singleton;

interface

type
  TSingleton = class
  private
    class var _instance: TSingleton;
  public
    //Global point of access to the unique instance
    class function Create: TSingleton;

    destructor Destroy; override;
  end;

implementation

{ TSingleton }

class function TSingleton.Create: TSingleton;
begin
  if (_instance = nil) then
    _instance:= inherited Create as Self;

  result:= _instance;
end;

destructor TSingleton.Destroy;
begin
  _instance:= nil;
  inherited;
end;

end.

I added the details to my original post: http://www.yanniel.info/2010/10/singleton-pattern-delphi.html