[fpc-pascal] TFPHashList help

[Graeme Geldenhuys]

Hi,

I have the following class and function that retrieves a object from a
internal TFPHashList. If the object isn't in the list, it is read from
a database, and then also inserted into the hashlist, before it gets
returned.

Does TFPHashTable also manage the objects it contains (or references)
like TObjectList.  If not (which I think it doesn't), that means when
TModuleFlyweightFactory gets destroyed, I need to free and empty the
internal TFPHashTable as well.  I'm not sure how I would to that
though.  Can is loop through the hashtable using the Items[] property
to free off the referenced object. Set that same Item to nil, and then
in the end, just .Free the FPHashTable?


interface section:

  TModuleFlyweightFactory = class(TObject)
  private
    FList: TFPHashTable;
    function GetModuleCount: integer;
  public
    constructor Create;
    destructor  Destroy; override;
    function    GetModule(pOID: TOID): TModule; overload;
    function    GetModule(pOIDAsString: string): TModule; overload;
    property    ModuleCount: integer read GetModuleCount;
  end;


implementation section:

function TModuleFlyweightFactory.GetModule(pOID: TOID): TModule;
var
  lData: TModule;
begin
  lData := TModule(FList.Items[pOID.AsString]);
  if lData <> nil then
    Result := lData
  else
  begin
    lData := TModule.Create;
    lData.OID.AsString := pOID.AsString;
    lData.ReadPK;

    if lData.ObjectState <> posEmpty then
      FList.Add(lData.OID.AsString, lData);  // only add if we know we
have something
    Result := lData;
  end;
end;


Regards,
  - Graeme -