Metode MVC – Apa Pengaruhnya Bagi Para Programmer?

Masih ingat saya ketika masa-masa saya masih maniak koding dari awal ketika membuat sebuah aplikasi. Hampir seluruh kodingan yang saya buat hanya menggunakan komponen-komponen dasar yang ada pada bahasa pemrograman tersebut, sedikit sekali saya memakai komponen eksternal atau tool pembantu. Pokoknya ngoding poll dari awal dan comot kodingan sana-sini dari internet dan ujung-ujungnya jadilah program gado-gado tanpa struktur yang jelas, saya sendiri pusing kalo disuruh ngeliat kodingan saya jaman dulu, waduh bikin mata serasa mau copot :nohope:

Teman sesama peneliti saya, Putra Setia Utama, sering menyarankan saya untuk menggunakan komponen yang sudah ada seperti YUI untuk interface web dan beberapa lainnya yang saya gak apal hehe soalnya dulu biasanya saya acuhkan hal seperti itu. Namun sejak tahun lalu saya mulai sadar betapa bodohnya saya, terus menerus mengoding dari awal hal yang sama secara berulang-ulang.

Tahun lalu saya “terpaksa” menggunakan framework untuk Java berbasis Model View Controller (MVC), yaitu Hibernate dan Spring, dikarenakan oleh tuntutan tempat dimana saya sedang praktek kerja lapangan (PKL) waktu itu. Bagi saya yang terbiasa ngoding dari awal, belajar menggunakan Hibernate dan Spring itu seperti neraka, pusing sekali saya waktu itu. Hibernate dengan konsep ORM-nya yang berbeda jauh dengan query SQL manual dalam pemrosesan data dan Spring dengan konsep MVC-nya yang ngebuat saya serasa seperti alien di dunia pemrograman.

1 bulan saya berkutat dengan Hibernate dan Spring akhirnya saya mendapatkan pencerahan hehe :siul: . Metode pemrograman yang dulu saya bisa membutuhkan 3 bulan untuk mengerjakan web berjenis databank, sekarang bisa saya kerjakan dalam waktu kurang dari 1 bulan. Dan jika ada revisi, saya tidak repot-repot lagi harus mengecek semua halaman web yang saya buat, karena dengan menggunakan framework hampir semuanya sudah terstruktur dengan rapih sehingga memudahkan saya untuk memodifikasi web tersebut.

Penggunaan framework MVC sangat membantu saya dan tentunya programmer lainnya, baik itu programmer web, desktop, atau mobile. Dengan menggunakan framework biasanya kita akan dibantu hal-hal seperti query database, manajemen source code, validasi data, keamanan, dan lain-lain. Setelah saya melihat berbagai macam hal yang dapat mempengaruhi kinerja programmer dengan menggunakan framework MVC saya langsung beralih menjadi programmer berbasis framework hehe, gak mau lagi saya disuruh ngoding secara manual yang ampe ratusan bahkan ribuan kodingan yang isinya kebanyakan validasti data, query, keamanan, dan lain-lain yang bersifat repetitif di setiap proyek aplikasi, tinggal programming santai saja saya hehe :linux2:

Saya menjadi sadar bahwa selama ini yang saya lakukan adalah memeras diri sendiri dan “reinvent the wheel”, artinya saya bersusah payah untuk melakukan hal yang sudah ada. Berikut saya berikan poin-poin penting dari keuntungan menggunakan framework MVC menurut saya:

1. Programmer akan sangat terbantu dalam membuat kodingan-kodingan yang bersifat repetitif
2. Source code secara otomatis akan mengikuti struktur file yang ada di framework tersebut sehingga memudahkan manajemen source code
3. Kebanyakan perusahaan sekarang membutuhkan programmer yang bisa menggunakan framework MVC, artinya peluang kerja semakin besar dibanding yang ngoding dari awal
4. Biasanya gaji programmer yang menggunakan framework MVC lebih mahal dibanding yang ngoding dari awal

Walaupun begitu, mengoding dari awal tetap diperlukan ketika kita belajar pemrgoraman. Soalnya dengan mengoding dari awal itulah kita bisa mengeri konsep dan basis pemrograman, kalau langsung menggunakan framework MVC kemungkinan besar anda akan bingung karena anda akan dijejali dengan berbagai macam konsep-konsep Object Oriented Programming (OOP) seperti inheritance, override, abstraction, dan lain-lain. Setelah kita mengerti konsep dan basis pemrograman barulah kita beralih ke penggunaan framework MVC.

Terakhir, walaupun penggunaan framework MVC memberikan kita banyak keuntungan tapi jika kita menggunakannya secara asal maka akan berdampak terbalik buat kita seperti program menjadi lebih berat untuk dijalankan dan lain-lain. Tetap kita harus teliti dalam mengoding dan memahami MVC secara mendalam agar aplikasi yang kita buat berjalan dengan nyaman. Saya pribadi memang agak susah untuk memahami konsep framework MVC pertama kalinya, tapi setelah anda terbiasa, bikin program udah tinggal libas aja hehe.

Selamat belajar dan kampanyekan programming sehat menggunakan framework MVC hehe.

---

* Untuk tambahan, berikut adalah framework MVC yang sudah pernah saya gunakan, siapa tau bermanfaat:

1. Java: Hibernate (Model) + Spring (View, Controller)
2. PHP: Doctrine (Model) + CodeIgniter (View, Controller), kebetulan untuk yang ini ada tutorial di jurnal ini di link ini

Disadur dari : http://www.teknojurnal.com/2010/02/24/framework-mvc-apa-pengaruhnya-bagi-para-programmer/

Delphi MVC

Main project file:

var
  Model: TModel;
  Controller: TController;
begin
  Application.Initialize;
  Application.CreateForm(TMainForm, MainForm);

  Model      := TModel.Create;
  Controller := TController.Create(Model, MainForm);

  Application.Run;

  Controller.Free;
  Model.Free;
end.

Model:

TModel = class(TSubject)
private
  FData: TStrings;
public
  constructor Create;
  destructor Destroy(); override;
  procedure AddLine(AText: string);
  property Data: TStrings read FData; // Do not write to this directly, since it doesn't call notify!
end;

Controller:

TController = class(TObserver)
private
  FModel: TModel;
  FView:  TMainForm;
public
  constructor Create(const AModel: TModel; AView: TMainForm);
  destructor Destroy(); override;
  procedure ButtonClick(Sender: TObject);
  procedure Refresh(ASubject: TSubject); override;
end;

The main form is working as the View, i have removed all code from it.

The controller registers itself as an observer and does all the logic:

constructor TController.Create(const AModel: TModel; AView: TMainForm);
begin
  inherited Create();
  FModel := AModel;
  FView  := AView;
  FModel.Register(Self);
  FView.Button1.OnClick := ButtonClick;
  FView.Button2.OnClick := ButtonClick;
  FView.Button3.OnClick := ButtonClick;
end;

destructor TController.Destroy;
begin
  FModel.UnRegister(Self);
  FView.Button1.OnClick := nil;
  FView.Button2.OnClick := nil;
  FView.Button3.OnClick := nil;
  inherited;
end;

procedure TController.Refresh(ASubject: TSubject);
begin
  FView.ListBox1.Items.BeginUpdate;
  try
    FView.ListBox1.Items.Assign(FModel.Data);
  finally
    FView.ListBox1.Items.EndUpdate;
  end;
end;

procedure TController.ButtonClick(Sender: TObject);
begin
  if Sender = FView.Button1 then begin
    FModel.AddLine('Hello');
  end else
  if Sender = FView.Button2 then begin
    FModel.AddLine('Hello World!');
  end else
  if Sender = FView.Button3 then begin
    FModel.AddLine(DateToStr(Now));
  end
end;

I cheated a little bit with the View <-> Controller relationship, but you should get the general idea :).

• The Controller has references to both View and Model.
• The View knows nothing about the Model.
• The Model knows nothing aboug the View.

PS: A diagram for the MVC pattern (the dotted lines represent Observer/Subject relationships):

MVC or MVP Pattern – Whats the difference?

Over the years I have mentored many developers on using design patterns and best practices. One question that keeps coming up over and over again is: What are the differences between the Model View Controller (MVC) and Model View Presenter (MVP) patterns? Surprisingly the answer is more complex than what you would suspect. Part of reasons I think many developers shy away from using either pattern is the confusion over the differences.

Before we dig into the differences let’s examine how the patterns work and the key benefits to using either one. Both (MVC & MVP) patterns have been use for several years and address a key OO principal namely separation of concerns between the UI and the business layers. There are a number of frameworks is use today that based on these patterns including: JAVA Struts, ROR, Microsoft Smart Client Software Factory (CAB), Microsoft Web Client Software Factory, and the recently announced ASP.Net MVC framework.

Model View Controller (MVC) Pattern

The MVC pattern is a UI presentation pattern that focuses on separating the UI (View) from its business layer (Model). The pattern separates responsibilities across three components: the view is responsible for rending UI elements, the controller is responsible for responding to UI actions, and the model is responsible for business behaviors and state management. In most implementation all three components can directly interact with each other and in some implementations the controller is responsible for determining which view to display (Front Controller Pattern),

Model View Presenter (MVP) Pattern

 

The MVP pattern is a UI presentation pattern based on the concepts of the MVC pattern. The pattern separates responsibilities across four components: the view is responsible for rending UI elements, the view interface is used to loosely couple the presenter from its view, the presenter is responsible for interacting between the view/model, and the model is responsible for business behaviors and state management. In some implementations the presenter interacts with a service (controller) layer to retrieve/persist the model. The view interface and service layer are commonly used to make writing unit tests for the presenter and the model easier.

Key Benefits

Before using any pattern a developers needs to consider the pros and cons of using it. There are a number of key benefits to using either the MVC or MVP pattern (See list below). But, there also a few draw backs to consider. The biggest drawbacks are additional complexity and learning curve. While the patterns may not be appropriate for simple solutions; advance solutions can greatly benefit from using the pattern. I’m my experience a have seen a few solutions eliminate a large amount of complexity but being re-factored to use either pattern.

·         Loose coupling – The presenter/controller are an intermediary between the UI code and the model. This allows the view and the model to evolve independently of each other.

·         Clear separation of concerns/responsibility

o    UI (Form or Page) – Responsible for rending UI elements

o    Presenter/controller – Responsible for reacting to UI events and interacts with the model

o    Model – Responsible for business behaviors and state management

·         Test Driven – By isolating each major component (UI, Presenter/controller, and model) it is easier to write unit tests. This is especially true when using the MVP pattern which only interacts with the view using an interface.

·         Code Reuse – By using a separation of concerns/responsible design approach you will increase code reuse. This is especially true when using a full blown domain model and keeping all the business/state management logic where it belongs.

·         Hide Data Access – Using these patterns forces you to put the data access code where it belongs in a data access layer. There a number of other patterns that typical works with the MVP/MVC pattern for data access. Two of the most common ones are repository and unit of work. (See Martin Fowler – Patterns of Enterprise Application Architecture for more details)

·         Flexibility/Adaptable – By isolating most of your code into the presenter/controller and model components your code base is more adaptable to change. For example consider how much UI and data access technologies have changed over the years and the number of choices we have available today. A properly design solution using MVC or MVP can support multi UI and data access technologies at the same time.

Key Differences

So what really are the differences between the MVC and MVP pattern. Actually there are not a whole lot of differences between them. Both patterns focus on separating responsibility across multi components and promote loosely coupling the UI (View) from the business layer (Model).  The major differences are how the pattern is implemented and in some advanced scenarios you need both presenters and controllers.

Here are the key differences between the patterns:

·         MVP Pattern

o    View is more loosely coupled to the model. The presenter is responsible for binding the model to the view.

o    Easier to unit test because interaction with the view is through an interface

o    Usually view to presenter map one to one. Complex views may have multi presenters.

·         MVC Pattern

o    Controller are based on behaviors and can be shared across views

o    Can be responsible for determining which view to display (Front Controller Pattern)

Hopefully you found this post interesting and it helped clarify the differences between the MVC and MVP pattern. If not, do not be discouraged patterns are powerful tools that can be hard to use sometimes. One thing to remember is that a pattern is a blue print and not an out of the box solutions. Developers should use them as a guide and modify the implementation according to their problem domain.

Reference : http://www.infragistics.com/community/blogs/todd_snyder/archive/2007/10/17/mvc-or-mvp-pattern-whats-the-difference.aspx

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;

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;

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;

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;

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;

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;

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;

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;

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;

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;

end;

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;

end;

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;

end;

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;

end;

end.

Referensi : http://altaifa.wordpress.com/2010/08/02/mvc-dalam-delphi-programming-ii-meniru-konsep-ci/