正在阅读：用简单的Tracer类来为应用写入跟踪用简单的Tracer类来为应用写入跟踪

destructor TTracer.Destroy;
begin
    if FOutput <> nil then FOutput := nil;
    inherited;
end;

procedure TTracer.SetOutput(const Value: IOutput);
begin
    FOutput := Value;
end;

procedure TTracer.Write(const aInfo: ITraceInfo);
begin
    if FOutput = nil then raise Exception.CreateFmt('没有创建输出目标%s!!!', []);
    FOutput.Write(aInfo);
end;

{ TStringTI }

constructor TStringTI.Create(data: string);
begin
    FData := Data;
end;

function TStringTI.ToString: string;
begin
    Result := FData;
end;

{ TStringLog }

constructor TFileLog.Create(const FileName: string);
begin
    FLogFile := FileName;
end;

procedure TFileLog.Write(const aInfo: ITraceInfo);
begin
    if not FileExists(FLogFile) then FileClose(FileCreate(FLogFile));
    with TStringList.Create do
    begin
        try
            LoadFromFile(FLogFile);
            Add(aInfo.ToString);
            SaveToFile(FLogFile);
        finally
            Free;
        end;
    end;
end;