MVC Dalam Delphi Programming II – Meniru Konsep CI

CATATAN: Jangan menggunakan variabel bertipe interface untuk menyimpan data bertipe TObject. Bikin Error!

CI atau Code Igniter mempunyai konsep mvc yang menarik. Dibanding Tulisan saya sebelumnya, model mvc yang ditawarkan oleh CIebih elegan. Dibandingkan konsep MVC yang saya gambarkan dulu, yang hanya memanggil/memanfaatkan prosedur konsep MVC CI memanfaatkan kelas. Dalam tutorial awal CI kita lihat contoh contoh kodingnya:

Controller:

View

Beberapa konsep yang perlu diperhatikan disini:

1. Kemunculan View diatur oleh controller

2. Apa (data apa) yang ditampilkan View di-supply oleh controller. Dalam definisi lengkap MVC, controller mendapatkan data dari Model (dapat berupa perintah sql dalam database).

3. Data yang dipertukarkan antara View dengan controller mempunyai tipe data generik, dalam bentuk list.

Konsep ini dapat diterapkan diterjemahkan di dalam delphi sebagai berikut:

- Controller seharusnya berupa Class

- Data harus bertipe generik. Karena Delphi strong type, hal tersebut dapat diakali dengan menggunakan data yang bertipe data objek, dan mempunyai property yang memungkinkan diakses dalam tipe data apapun.

Saya menerjemahkan model MVC code igniter tersebut di atas menjadi sebagai berikut:

unit con_canvaser;

interface

uses Windows, Messages, SysUtils, Variants, Classes, Forms,

Dialogs, Controls, TypInfo, SDKHelper;

type

TErrMsg = string;

IMvcData = interface(IInterface)

['{7293B5D3-FC1F-4DB5-B764-3F94AD2427C8}']

procedure SetValueStr(const Name: string; const Value: string);

procedure SetValueInt(const Name: string; const Value: Integer);

procedure SetValueDouble(const Name: string; const Value: Double);

procedure SetValueCurrency(const Name: string; const Value: Currency);

procedure SetValueVar(const Name: string; const Value: Variant);

procedure SetValueDate(const Name: string; const Value: TDateTime);

procedure SetValueObj(const Name: string; const Value: TObject);

function GetValueStr(const Name: string): string;

function GetValueInt(const Name: string): Integer;

function GetValueDouble(const Name: string): Double;

function GetValueCurrency(const Name: string): Currency;

function GetValueVar(const Name: string): Variant;

function GetValueDate(const Name: string): TDateTime;

function GetValueObj(const Name: string): TObject;

property ValueStr[const Name: string]: string read GetValueStr Write SetValueStr;

property ValueInt[const Name: string]: Integer read GetValueInt Write SetValueInt;

property ValueDouble[const Name: string]: Double read GetValueDouble Write SetValueDouble;

property ValueCurrency[const Name: string]: Currency read GetValueCurrency Write SetValueCurrency;

property ValueVar[const Name: string]: Variant read GetValueVar Write SetValueVar;

property ValueDate[const Name: string]: TDateTime read GetValueDate Write SetValueDate;

property ValueObj[const Name: string]: TObject read GetValueObj Write SetValueObj;

end;

TDateTimeVar = class(TInterfacedObject,IInterface)

private

FData: TDateTime;

public

constructor Create(InitValue: TDateTime);

property Data: TDateTime read FData write FData;

end;

TMvcData = class(TInterfacedObject, IMvcData)

private

FList: TStringList;

public

constructor Create;

destructor Destroy; override;

procedure SetValueStr(const Name: string; const Value: string);

procedure SetValueInt(const Name: string; const Value: Integer);

procedure SetValueDouble(const Name: string; const Value: Double);

procedure SetValueCurrency(const Name: string; const Value: Currency);

procedure SetValueVar(const Name: string; const Value: Variant);

procedure SetValueDate(const Name: string; const Value: TDateTime);

procedure SetValueObj(const Name: string; const Value: TObject);

function GetValueStr(const Name: string): string;

function GetValueInt(const Name: string): Integer;

function GetValueDouble(const Name: string): Double;

function GetValueCurrency(const Name: string): Currency;

function GetValueVar(const Name: string): Variant;

function GetValueDate(const Name: string): TDateTime;

function GetValueObj(const Name: string): TObject;

property ValueStr[const Name: string]: string read GetValueStr Write SetValueStr;

property ValueInt[const Name: string]: Integer read GetValueInt Write SetValueInt;

property ValueDouble[const Name: string]: Double read GetValueDouble Write SetValueDouble;

property ValueCurrency[const Name: string]: Currency read GetValueCurrency Write SetValueCurrency;

property ValueVar[const Name: string]: Variant read GetValueVar Write SetValueVar;

property ValueDate[const Name: string]: TDateTime read GetValueDate Write SetValueDate;

property ValueObj[const Name: string]: TObject read GetValueObj Write SetValueObj;

end;

IView = interface(IInterface)

['{8318E550-2DC0-4A2A-B45C-C8A636D24702}']

procedure GetInitData(MvcData: IMvcData);

function GetOutputData: IMvcData;

end;

IController = interface

['{4F6CCA74-90BD-46EF-8507-26A1C9F1FDAF}']

procedure DoResponse;

function GetData: IMvcData;

procedure SetData(Data: IMvcData);

property Data: IMvcData read GetData write SetData;

end;

TController = class(TInterfacedObject, IController)

private

FMvcData: IMvcData;

public

procedure DoResponse;

function GetData: IMvcData;

procedure SetData(Data: IMvcData);

property Data: IMvcData read GetData write SetData;

constructor Create; virtual;

end;

{ Canvaser Controller

Dengan ini selurut tabel-tabel rujukan combobox diloag

}

TCanvaserController = class(TController)

{daftar yang diload di sini adalah untuk mengisi combo box,

cuma ada dua field sebagai key dan lookup value saja}

Procedure ReloadDummy;

procedure ReloadDaftarKota;

procedure ReloadDaftarPropinsi;

procedure ReloadDaftarSales;

procedure ReloadDaftarStatus;

procedure ReloadDaftarJenisTransaksi;

constructor Create; override; {reload All combo reference}

end;

TPenjualanController = class(TCanvaserController)

constructor Create; override;

end;

TMasterOutletController = class(TCanvaserController)

function IsOutletExist: Boolean;

function IsBlokir: Boolean;

function SetBlokir: TErrMsg; //return ” if success, otherwise false!

function SetUnBlokir: TErrMsg;

function Delete: TErrMsg;

function PostUpdated: TErrMsg;

function PostInserted(var NewCustId: string): TErrMsg;

constructor Create; override;

end;

{

TMasterSalesController = class(TCanvaserController)

function IsOutletExist: Boolean;

function IsBlokir: Boolean;

function SetBlokir: TErrMsg; //return ” if success, otherwise false!

function SetUnBlokir: TErrMsg;

function Delete: TErrMsg;

function PostUpdated: TErrMsg;

function PostInserted: TErrMsg;

constructor Create; override;

end;

}

//IDataset harus punya 2 field, satu bernama Key satu bernama Value , sementara ini berlaku untuk Key Integer dan Value String

procedure InitList(Source: IDataset; DestList: TStringList);

//mendapat index dari keyval list

function GetMvcListIndex(Items: TStrings; KeyVal: string): Integer;

//mem-free object-object List

procedure FreeOwnObjets(List: TStringList);

{General Dialogs}

function MsgDlgConfirm(Msg: string): Boolean;

procedure MsgDlgInformation(Msg: string);

procedure MsgDlgWarning(Msg: string);

procedure MsgDlgError(Msg: string);

{General View Fungtions}

procedure DisableControls(Controls: array of TControl);

procedure EnableControls(Controls: array of TControl);

{mencek apakah input terdapat karakter yang dilarang}

function Validate(Controls: array of TControl; PropName: string): Boolean;

implementation

uses mod_canvaser;

{ TMvcData }

constructor TMvcData.Create;

begin

FList:= TStringList.Create;

end;

destructor TMvcData.Destroy;

begin

FreeOwnObjets(FList);

FreeAndNil(FList);

inherited;

end;

function TMvcData.GetValueInt(const Name: string): Integer;

begin

if FList.Values[Name]<>” then

Result:= StrToInt(FList.Values[Name])

else

Result:= -1;

end;

function TMvcData.GetValueStr(const Name: string): string;

begin

Result:= FList.Values[Name];

end;

function TMvcData.GetValueObj(const Name: string): TObject;

var Index: Integer;

begin

Index:= ValueInt[Name+'INDEX'];

if Index>0 then begin

ShowMessage(‘[GET] Found Obj Name = ‘ + Name);

Result:= FList.Objects[Index];

end else begin

ShowMessage(‘[GET] NOT Found Obj Name = ‘ + Name);

Result:= nil;

end;

function TMvcData.GetValueVar(const Name: string): Variant;

var Index: Integer;

begin

Result:= Null;

if FList.Find(Name,Index) then

Result:= FList.Values[Name];

end;

function TMvcData.GetValueCurrency(const Name: string): Currency;

begin

Result:=0.0;

if Trim(FList.Values[Name])<>” then

Result:= StrToCurr(FList.Values[Name]);

end;

function TMvcData.GetValueDate(const Name: string): TDateTime;

var

Index: Integer;

begin

if FList.Find(Name,Index) then begin

Result:= TDateTimeVar(FList.Objects[Index]).Data;

end;

function TMvcData.GetValueDouble(const Name: string): Double;

var

Index: Integer;

Value: string;

begin

Result:= 0.0;

if FList.Find(Name,Index) then begin

Value:= FList.Values[Name];

if Trim(Value)<>” then

Result:= StrToFloat(Value);

end;

procedure TMvcData.SetValueInt(const Name: string; const Value: Integer);

begin

FList.Values[Name]:= IntToStr(Value);

end;

procedure TMvcData.SetValueStr(const Name, Value: string);

begin

FList.Values[Name]:= Value;

end;

procedure TMvcData.SetValueObj(const Name: string; const Value: TObject);

var

Index: Integer;

begin

Index:= ValueInt[Name+'INDEX'];

if Index>0 then begin

ShowMessage(‘[SET] Found Obj Name = ‘ + Name);

FList.Objects[Index].Free;

FList.Objects[Index]:= Value;

end else begin

ShowMessage(‘[SET] NOT Found Obj Name = ‘ + Name);

ValueInt[Name+'INDEX']:= FList.AddObject(Name, Value);

end;

procedure TMvcData.SetValueVar(const Name: string; const Value: Variant);

begin

FList.Values[Name]:= VarToStr(Value);

end;

procedure TMvcData.SetValueCurrency(const Name: string; const Value: Currency);

begin

FList.Values[Name]:= CurrToStr(Value);

end;

procedure TMvcData.SetValueDate(const Name: string; const Value: TDateTime);

var

Index: Integer;

begin

if FList.Find(Name,Index) then

TDateTimeVar(FList.Objects[Index]).Data:= Value

else

FList.AddObject(Name,TDateTimeVar.Create(Value));

end;

procedure TMvcData.SetValueDouble(const Name: string; const Value: Double);

begin

FList.Values[Name]:= FloatToStr(Value);

end;

{ TController }

constructor TController.Create;

begin

FMvcData:= TMvcData.Create;

//ShowMessage(‘Tcontroller create’);

end;

procedure TController.DoResponse;

begin

end;

function TController.GetData: IMvcData;

begin

Result:= FMvcData;

end;

procedure TController.SetData(Data: IMvcData);

begin

FMvcData:= Data;

end;

{ TCanvaserController }

constructor TCanvaserController.Create;

begin

inherited;

//ShowMessage(‘TCanvaserController Create’);

OpenDatabaseConnection;

ReloadDummy; {

Sepertinya terdapat BUG pada TStringList Object,

yakni, object yang di-assign (melalui AddObject) yang pertama, tidak bisa diakses.

maka butuh dummy sebagai objek awal, agar objek berikutnya dapat diakses.

}

ReloadDaftarKota;

ReloadDaftarPropinsi;

ReloadDaftarSales;

//ReloadDaftarStatus;

//ReloadDaftarJenisTransaksi;

//ShowMessage(‘TCanvaserController Create – END’);

end;

procedure TCanvaserController.ReloadDaftarJenisTransaksi;

var

StrList: TStringList;

begin

StrList:= TStringList.Create;

InitList(QueryM_TRANSAKSI,StrList);

Data.ValueObj['ObjDaftarJenisTransaksi']:= StrList;

StrList:= nil;

end;

procedure TCanvaserController.ReloadDummy;

var

StrList: TStringList;

begin

StrList:= TStringList.Create;

Data.ValueObj['ObjDummy']:= StrList;

StrList:= nil;

end;

procedure TCanvaserController.ReloadDaftarKota;

var

StrList: TStringList;

begin

ShowMessage(‘reload daftar kota, Kode Propinsi = ‘ + Data.ValueStr['KodePropinsi']);

StrList:= TStringList.Create;

InitList(QueryM_KOTA(Data.ValueStr['KodePropinsi']),StrList);

//InitList(QueryM_KOTA,StrList);

Data.ValueObj['ObjDaftarKota']:= StrList;

StrList:= nil;

end;

procedure TCanvaserController.ReloadDaftarPropinsi;

var

StrList: TStringList;

begin

StrList:= TStringList.Create;

InitList(QueryM_PROPINSI,StrList);

Data.ValueObj['ObjDaftarPropinsi']:= StrList;

StrList:= nil;

end;

procedure TCanvaserController.ReloadDaftarSales;

var

StrList: TStringList;

begin

StrList:= TStringList.Create;

InitList(QuerySALES,StrList);

Data.ValueObj['ObjDaftarSales']:= StrList;

StrList:= nil;

end;

procedure TCanvaserController.ReloadDaftarStatus;

var

StrList: TStringList;

begin

StrList:= TStringList.Create;

InitList(QueryM_STATUS,StrList);

Data.ValueObj['ObjDaftarStatus']:= StrList;

StrList:= nil;

end;

{ TPenjualanController }

constructor TPenjualanController.Create;

var

JnsTransList, NoPakList, ProdukList: TStringList;

begin

inherited;

JnsTransList:= TStringList.Create;

NoPakList:= TStringList.Create;

ProdukList:= TStringList.Create;

//list item for ‘ListJnsTrans’

InitList(QueryM_TRANSAKSI,JnsTransList);

Data.ValueObj['ObjListJnsTrans']:= JnsTransList;

InitList(QueryM_TRANSAKSI,NoPakList);

Data.ValueObj['ObjListNoPak']:= NoPakList;

InitList(QueryM_TRANSAKSI,ProdukList);

Data.ValueObj['ObjListProduk']:= ProdukList;

Data.ValueDate['TglPenjualan']:= Now;

ProdukList:= nil;

NoPakList:= nil;

JnsTransList:= nil;

FreeAndNil(JnsTransList);

FreeAndNil(NoPakList);

FreeAndNil(ProdukList);

end;

{ TDateTimeVar }

constructor TDateTimeVar.Create(InitValue: TDateTime);

begin

Data:= InitValue;

end;

procedure InitList(Source: IDataset; DestList: TStringList);

var

ObjList: TMvcData;

begin

DestList.Clear;

with Source do begin

while not eof do begin

ObjList:= TMvcData.Create;

ObjList.ValueStr['KeyVal']:= FieldByName(‘KeyVal’).AsString;

DestList.AddObject(FieldByName(‘LookUpVal’).AsString, ObjList);

Next;

end;

ObjList:= nil;

end;

function GetMvcListIndex(Items: TStrings; KeyVal: string): Integer;

var

List: TStringList;

i: Integer;

begin

Result:= -1;

List:= TStringList(Items);

for i:= 0 to List.Count – 1 do

if TMvcData(List.Objects[i]).ValueStr['KeyVal'] = KeyVal then begin

Result:= i;

Break;

end;

procedure FreeOwnObjets(List: TStringList);

var i: Integer;

begin

if List.Count<1 then exit;

for i:= 0 to List.Count – 1 do

if Assigned(List.Objects[i]) then begin

if List.Objects[i] is TStringList then

FreeOwnObjets(TStringList(List.Objects[i])); {recursive}

List.Objects[i].Free;

end;

{General Dialogs}

function MsgDlgConfirm(Msg: string): Boolean;

begin

Result:= MessageDlg(Msg, mtConfirmation, mbOKCancel,0) = mrOk;

end;

procedure MsgDlgInformation(Msg: string);

begin

MessageDlg(Msg, mtInformation, [mbOK],0);

end;

procedure MsgDlgWarning(Msg: string);

begin

MessageDlg(Msg, mtWarning, [mbOK],0);

end;

procedure MsgDlgError(Msg: string);

begin

MessageDlg(Msg, mtError, [mbOK],0);

end;

{General View Fungtions}

procedure DisableControls(Controls: array of TControl);

var i: Integer;

begin

for i:= Low(Controls) to High(Controls) do

Controls[i].Enabled:= False;

end;

procedure EnableControls(Controls: array of TControl);

var i: Integer;

begin

for i:= Low(Controls) to High(Controls) do

Controls[i].Enabled:= True;

end;

{ TMasterOutletController }

function TMasterOutletController.IsBlokir: Boolean;

begin

Result:= Data.ValueStr['IsBlokir'] = ’1′;

end;

function TMasterOutletController.IsOutletExist: Boolean;

var

sDataset: IDataset;

begin

Result:= False;

sDataset:= QueryCustomer(Data.ValueStr['CustId']);

if not Assigned(sDataset) then exit;

Result:= sDataset.RecordCount>0;

Data.ValueStr['CustNama']:=SDataset.FindField(‘NAMA’).AsString;

Data.ValueStr['CustKontak']:=SDataset.FindField(‘KONTAK’).AsString;

Data.ValueStr['CustAlamat']:=SDataset.FindField(‘ALAMAT’).AsString;

Data.ValueStr['CustTelepon']:=SDataset.FindField(‘NO_TELPON’).AsString;

Data.ValueStr['CustRekening']:=SDataset.FindField(‘NO_REKENING’).AsString;

Data.ValueStr['KodePropinsi']:=SDataset.FindField(‘K_PROPINSI’).AsString;

Data.ValueStr['KodeKota']:=SDataset.FindField(‘K_KOTA’).AsString;

Data.ValueStr['IsBlokir']:=SDataset.FindField(‘IS_BLOKIR’).AsString;

Data.ValueStr['SalesId']:=SDataset.FindField(‘SALES_ID’).AsString;

end;

function TMasterOutletController.PostInserted(var NewCustId: string): TErrMsg;

var

CUST_ID, Err_Code, Err_msg: String;

begin

try

with Data do begin

{ CUST_ID GENERATE OTOMATIS

procedure OutletInsert(CUST_ID, NAMA, KONTAK, ALAMAT, NO_TELPON, K_KOTA, K_PROPINSI,

NO_REKENING, SALES_ID, IS_BLOKIR, USER_ID: string);}

OutletInsert(

ValueStr['CustNama'], ValueStr['CustKontak'], ValueStr['CustAlamat'],

ValueStr['CustTelepon'], ValueStr['KodeKota'], ValueStr['KodePropinsi'],

ValueStr['CustRekening'], ValueStr['SalesId'], ValueStr['IsBlokir'],

ValueStr['UserId'], CUST_ID, Err_Code, Err_msg

);

if Err_Code<>” then

Result:= Format(‘\n[INSERT ERROR]\n%s’ ,[Err_msg])

else

NewCustId:= CUST_ID;

end;

except

on E:Exception do Result:= Format(‘\n[INSERT ERROR]\n%s’ ,[E.Message]);

end;

function TMasterOutletController.PostUpdated: TErrMsg;

begin

try

with Data do begin

{procedure OutletUpdate(CUST_ID, NAMA, KONTAK, ALAMAT, NO_TELPON, K_KOTA, K_PROPINSI,

NO_REKENING, SALES_ID, IS_BLOKIR, USER_ID: string);}

OutletUpdate(

ValueStr['CustId'], ValueStr['CustNama'], ValueStr['CustKontak'], ValueStr['CustAlamat'],

ValueStr['CustTelepon'], ValueStr['KodeKota'], ValueStr['KodePropinsi'],

ValueStr['CustRekening'], ValueStr['SalesId'], ValueStr['IsBlokir'],

ValueStr['UserId']

);

end;

except

on E:Exception do

Result:= Format(‘\n[UPDATE ERROR]\n%s’ ,[E.Message]);

end;

function TMasterOutletController.SetBlokir: TErrMsg;

begin

with Data do begin

ValueStr['IsBlokir']:=’1′; //representasi kondisi saat ini

try

OutletSetBlokir(’1′,ValueStr['CustId'], ValueStr['UserId']);

except

on E:Exception do Result:= E.Message;

end;

function TMasterOutletController.SetUnBlokir: TErrMsg;

begin

with Data do begin

ValueStr['IsBlokir']:=’0′; //representasi kondisi saat ini

try

OutletSetBlokir(’0′,ValueStr['CustId'], ValueStr['UserId']);

except

on E:Exception do Result:= E.Message;

end;

constructor TMasterOutletController.Create;

begin

inherited;

//ShowMessage(‘MasterOutletController create’);

end;

function TMasterOutletController.Delete: TErrMsg;

begin

with Data do begin

try

OutletDelete(ValueStr['CustId'], ValueStr['UserId']);

except

on E:Exception do Result:= Format(‘[DELETE ERROR]\n%s’,[E.Message]);

end;

function Validate(Controls: array of TControl; PropName: string): Boolean;

var

i: Integer;

PropValue: string;

begin

Result:= True;

for i:= Low(Controls) to High(Controls) do begin

PropValue:= GetPropValue(Controls[i],PropName);

if Pos(””,PropValue)>0 then begin

Result:= False;

if Controls[i] is TWinControl then TWinControl(Controls[i]).SetFocus;

Break;

end;

end.

Like this:

Be the first to like this post.

Artikel ini ditulis pada Agustus 2, 2010, 9:04 am dalam kategori Delphi. Anda bisa mengikuti tanggapan atas artikel ini melalui RSS 2.0. Baik komentar maupun ping saat ini ditutup.

Altaifa Software Developer

MVC Dalam Delphi Programming II – Meniru Konsep CI

Like this:

Arsip

Follow “Altaifa Software Developer”