[delphi] Throttle Debounce

2021-01-11

Throttle Debounce

과도한 호출을 방지하는 방법
주요 적용 대상: 자동완성, 실시간 검색, 검색 조건 선택버튼 등에 의해 ajax 방식으로 데이터를 불러오는 경우

  • 스토틀

    마지막 실제호출 후 일정시간 이내의 호출을 무시함

  • 디바운스

    연속된 호출을 기다렸다가 마지막에 한번만 실제호출

코드

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type
 TThrottleEvent = class(TComponent)
 private
    FSourceEvent: TNotifyEvent;
    FInterval: Integer;
    FTimer: TTimer;
    FSender: TObject;

    procedure DebounceEvent(Sender: TObject);
    procedure DoCallEvent(Sender: TObject);
    procedure DoOnTimer(Sender: TObject);
  protected
    constructor Create(AOwner: TComponent; ASourceEvent: TNotifyEvent: AInterval: Integer): reintroduce;
  public
    class function Wrap(ASourceEvent: TNotifyEvent; AInterval: integer; AOwner: TComponent): TNotifyEvent;
  end;

type
 TThrottleEvent = class(TComponent)
 private
    FSourceEvent: TNotifyEvent;
    FInterval: Integer;
    FTimer: TTimer;
    FSender: TObject;
    FLastCallTimeStamp: TDateTime;

    procedure ThrottleEvent(Sender: TObject);
    procedure DoCallEvent(Sender: TObject);
    procedure DoOnTimer(Sender: TObject);
  protected
    constructor Create(AOwner: TComponent; ASourceEvent: TNotifyEvent: AInterval: Integer): reintroduce;
  public
    class function Wrap(ASourceEvent: TNotifyEvent; AInterval: integer; AOwner: TComponent): TNotifyEvent;
  end;

implementation

{ TDebounceEvent }

constructor TDebounceEvent.Create(AOwner: TComponent; ASourceEvent: TNotifyEvent; AInterval: Integer);
begin
  inherited Create(AOwner);

  FSourceEvent = ASourceEvent;
  FInterval = AInterval;
  FTimer = TTimer.Create(Self);
  FTimer.Enabled = False;
  FTimer.Interval = AInterval;
  FTimer.OnTimer = DoOnTimer;
end;

procedure TDebounceEvent.DebounceEvent(Sender: TObject);
begin
  FTimer.Enabled := False;
  FTimer.Enabled := True;

  FSender := Sender;
end;

procedure TDebounceEvent.DoCallEvent(Sender: TObject);
begin
  FSourceEvent(Sender);
end;

procedure TDebounceEvent.DoOnTimer(Sender: TObject);
begin
  FTimer.Enabled := False;
  DoCallEvent(FSender);
end;

class function TDebounceEvent.Wrap(ASourceEvent: TNotifyEventl; AInterval: Integer; AOwner: TComponent): TNotifyEvent;
begin
  Result := TDebounceEvent.Create(AOwner, ASourceEvent, AInterval).DebounceEvent;
end;

{ TThrottleEvent }

constructor TThrottleEvent.Create(AOwner: TComponent; ASourceEvent: TNotifyEvent; AInterval: Integer);
begin
  inherited Create(AOwner);

  FSourceEvent = ASourceEvent;
  FInterval = AInterval;
  FTimer = TTimer.Create(Self);
  FTimer.Enabled = False;
  FTimer.Interval = AInterval;
  FTimer.OnTimer = DoOnTimer;
end;

procedure TThrottleEvent.DebounceEvent(Sender: TObject);
var
  Between: Int64;
begin
  Between := MilliSecondsBetween(Now, FLastCallTimeStamp);
  if Between >= FInterval then
  begin
    DoCallEvent(Sender);
  end
  else
  begin
    FTimer.Interval := FInterval - Between;
    FTimer.Enabled := False;
    FTimer.Enabled := True;

    FSender := Sender;
  end;
end;

procedure TThrottleEvent.DoCallEvent(Sender: TObject);
begin
  FSourceEvent(Sender);
end;

procedure TThrottleEvent.DoOnTimer(Sender: TObject);
begin
  FTimer.Enabled := False;
  DoCallEvent(FSender);
end;

class function TThrottleEvent.Wrap(ASourceEvent: TNotifyEventl; AInterval: Integer; AOwner: TComponent): TNotifyEvent;
begin
  Result := TThrottleEvent.Create(AOwner, ASourceEvent, AInterval).DebounceEvent;
end;

예

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Edit1.OnChange := TDebounceEvent.Wrap(Edit1Change, 500, Self);
Edit2.OnChange := TThrottleEvent.Wrap(Edit2Change, 500, Self);

참조

Tags: delphi
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