program Demo1;

{

  Create Date: 2014-06-29

  Author: P.S.M

  1.接口Demo1

}

{$APPTYPE CONSOLE}

uses

  SysUtils;

{定义接口}

type

 ITestInterface = interface

   {GUID通过CTRL+G自动产生}

   ['{15EAD871-2B5E-4F51-A14E-7D518A2371EF}']

   procedure Test;

 end;

{TInterfacedObject 实现了_AddRef, _Release方法可以自动释放对象}

 TTest1 = class(TInterfacedObject, ITestInterface)

 public

   {接口实现}

   procedure  ITestInterface.Test = GetTest;

   {测试接口}

   procedure GetTest;

   {重载Destroy方法}

   destructor Destroy;override;

 end;

 TTest2 = class(TInterfacedObject, ITestInterface)

 public

   {接口实现}

   procedure Test;

   {重载Destroy方法}

   destructor Destroy;override;

 end;

{ TTest }

destructor TTest1.Destroy;

begin

  WriteLn('对象1释放了');

  sleep(2000);

  inherited Destroy;

end;

procedure TTest1.GetTest;

begin

    WriteLn('接口1');

end;

{ TTest2 }

destructor TTest2.Destroy;

begin

  WriteLn('对象2释放了');

  sleep(2000);

  inherited Destroy;

end;

procedure TTest2.Test;

begin

  WriteLn('接口2');

end;

procedure Output(Obj: ITestInterface);

begin

    Obj.Test;

end;

var

 ITest1, ITest2: ITestInterface;

begin

   {接口什么时候释放？ 当它的引用计数为0是自动释放，作用域有效在函数体bend end，函数退出时自动减少引用计数 }

  try

    ITest1 := TTest1.Create;

    ITest2 := TTest2.Create;

    Output(Itest1);

    OutPut(ITest2);

  except

    on E: Exception do

      Writeln(E.ClassName, ': ', E.Message);

  end;

end.