main.pas

Java实例入门

unit Main;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TMainForm = class(TForm)
    Button1: TButton;
    ListBox1: TListBox;
    procedure Button1Click(Sender: TObject);
  private
    procedure ThreadsDone(Sender: TObject);
  end;

  TFooThread = class(TThread)
  protected
    procedure Execute; override;
  end;

var
  MainForm: TMainForm;

implementation

{$R *.DFM}

const
  MaxSize = 127;

var
  NextNumber: Integer = 0;
  DoneFlags: Integer = 0;
  GlobalArray: array[0..MaxSize] of Integer;
  CS: TRTLCriticalSection;  //声明一个临界区记录变量

function GetNextNumber: Integer;
begin
  inc(NextNumber);       // 全局变量NextNumber加1
  Result := NextNumber;  // 返回全局变量NextNumber
end;

procedure TFooThread.Execute;
var
  i: Integer;
begin
  OnTerminate := MainForm.ThreadsDone;
  EnterCriticalSection(CS);           // 进入临界区
  //下面为需要保护的资源
  for i := 0 to MaxSize do
  begin
    GlobalArray[i] := GetNextNumber;  // 为每个数组元素赋值
    Sleep(5);                         // 让线程睡眠一会
  end;
  LeaveCriticalSection(CS);           // 离开临界区
end;

procedure TMainForm.ThreadsDone(Sender: TObject);
var
  i: Integer;
begin
  inc(DoneFlags);
   for i := 0 to MaxSize do  // 将每个数组元素值添加到列表框
      Listbox1.Items.Add(IntToStr(GlobalArray[i]));
  if DoneFlags = 2 then   // 确保两个线程已执行完毕
      DeleteCriticalSection(CS);   //删除临界区
end;

procedure TMainForm.Button1Click(Sender: TObject);
begin
  InitializeCriticalSection(CS); //初始化临界区
  {创建两个线程}
  TFooThread.Create(False);
  TFooThread.Create(False);
end;

end.