关于VisiBroker For Delphi的使用2(3)

var

I: Integer;

begin

FCSect.Enter;

try

for I := 0 to Length(FModules) - 1 do

if FModules[I].Module = DataModule then

FModules[I].InUse := False;

ReleaseSemaphore(FSemaphore, 1, nil);

finally

FCSect.Leave;

end;

end;

function TModulePooler.GetModule: TDataModule;

var

I: Integer;

begin

Result := nil;

if WaitForSingleObject(FSemaphore, 5000) = WAIT_TIMEOUT then

raise Exception.Create('Server too busy');

FCSect.Enter;

try

if Length(FModules) = 0 then

begin

SetLength(FModules, PoolSize);

for I := 0 to PoolSize - 1 do

begin

FModules[I].InUse := False;

FModules[I].Module := FModuleClass.Create(Application);

end;

end;

for I := 0 to Length(FModules) - 1 do

if not FModules[I].InUse then

begin

FModules[I].InUse := True;

Result := FModules[I].Module;

Break;

end;

finally

FCSect.Leave;

end;

//检查曾经是否连接

if not Assigned(Result) then

raise Exception.Create('Pool is out of capacity');

end;

initialization

ModulePooler := TModulePooler.Create;

finalization

ModulePooler.Free;

end.

//本单元是一个通用的方法单元，当然您也可以采用其他的方法来完成这样的一个功能

//DataModule单元

unit dmEmployee;

interface

uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

Db, DBTables, Provider;

type

TdmEmploy = class(TDataModule)

Session1: TSession;

EmployeeDatabase: TDatabase;

qryEmployee: TQuery;

proEmployee: TDataSetProvider;

private

{ Private declarations }

public

{ Public declarations }

end;

var

dmEmploy: TdmEmploy;

implementation

{$R *.DFM}

end.

//服务器的主单元

unit ServerMain;

interface

uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

Grids, DBGrids, Db, DBTables, StdCtrls, Corba, Employee_I, Employee_C,

Employee_S, Employee_Impl；

type

TForm1 = class(TForm)

Label1: TLabel;

procedure FormCreate(Sender: TObject);

private

{ Private declarations }

procedure CorbaInit;

public

{ Public declarations }

hitcount : integer;

end;

var

Form1: TForm1;

myDBServer : Employee;

implementation

{$R *.DFM}

procedure TForm1.CorbaInit;

begin

CorbaInitialize;

myDBServer := TEmployeeSkeleton.Create('myServer', TEmployee.Create);

Boa.ObjIsReady( myDBServer as _Object );

end;

procedure TForm1.FormCreate(Sender: TObject);

begin

CorbaInit;

end;

end.

//客户端程序

interface

uses

Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

StdCtrls, Grids, Corba, Employee_i, Employee_c, Db, DBClient, ExtCtrls,

DBCtrls, DBGrids;

type

TForm1 = class(TForm)

Button1: TButton;

DBGrid1: TDBGrid;

cdsEmployee: TClientDataSet;

DataSource1: TDataSource;

edtEmployeeName: TEdit;

Memo1: TMemo;

Label1: TLabel;

procedure FormCreate(Sender: TObject);

procedure Button1Click(Sender: TObject);

private

{ Private declarations }

myEmployee : Employee;

public

{ Public declarations }

end;

var

Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);

begin

myEmployee := TEmployeeHelper.bind;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

cdsEmployee.Data := myEmployee.getEmployeesByName(edtEmployeeName.Text);

cdsEmployee.Open;

end;

end.

我想大家应该可以看得懂上面的程序，如果看不懂也不要紧，下一次我将围绕这个实例展开一系列的问题描述并会同时于COM /MIDAS进行比较说明，为了让大家留下一个思维的空间我在这里就不多说了。还是那一句话下次再见！


作者：赵普昉

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