Delphi接口

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.