Open Source "Logging Facade" für Pascal auf Github

[Sir Rufo]

Wenn du einen Logger implementierst, dann musst du immer ganz schön viel Boilerplate-Code schreiben.

Da würde ich noch ein Interface mit Wrapper dazwischen schieben:

Delphi-Quellcode:

unit djLogWriter;

interface

uses
  System.SysUtils,
  djLogAPI;

type
  TLogLevel  = ( llTrace, llDebug, llInfo, llWarn, llError );
  TLogLevels = set of TLogLevel;

type
  IWriteLog = interface
    procedure WriteMessage( const ALevel: TLogLevel; const AName, AMessage: string; const AException: Exception );
  end;

  TLogWriterWrapper = class( TInterfacedObject, ILogger )
  private { fields }
    FName     : string;
    FWriter   : IWriteLog;
    FLogFilter: TLogLevels;
    procedure SendToWriter( const ALevel: TLogLevel; const AMessage: string; const AException: Exception ); inline;
  private { ILogger }
    procedure Debug( const AMsg: string ); overload;
    procedure Debug( const AFormat: string; const AArgs: array of const ); overload;
    procedure Debug( const AMsg: string; const AException: Exception ); overload;

    procedure Error( const AMsg: string ); overload;
    procedure Error( const AFormat: string; const AArgs: array of const ); overload;
    procedure Error( const AMsg: string; const AException: Exception ); overload;

    procedure Info( const AMsg: string ); overload;
    procedure Info( const AFormat: string; const AArgs: array of const ); overload;
    procedure Info( const AMsg: string; const AException: Exception ); overload;

    procedure Warn( const AMsg: string ); overload;
    procedure Warn( const AFormat: string; const AArgs: array of const ); overload;
    procedure Warn( const AMsg: string; const AException: Exception ); overload;

    procedure Trace( const AMsg: string ); overload;
    procedure Trace( const AFormat: string; const AArgs: array of const ); overload;
    procedure Trace( const AMsg: string; const AException: Exception ); overload;

    function IsDebugEnabled: Boolean;
    function IsErrorEnabled: Boolean;
    function IsInfoEnabled: Boolean;
    function IsWarnEnabled: Boolean;
    function IsTraceEnabled: Boolean;

    function Name: string;
  public
    constructor Create( const AName: string; const AWriter: IWriteLog; const ALogFilter: TLogLevels );
  end;

implementation

{ TLogWriterWrapper }

constructor TLogWriterWrapper.Create( const AName: string; const AWriter: IWriteLog; const ALogFilter: TLogLevels );
begin
  inherited Create;
  FName      := AName;
  FWriter    := AWriter;
  FLogFilter := ALogFilter;
end;

procedure TLogWriterWrapper.Debug( const AMsg: string );
begin
  SendToWriter( llDebug, AMsg, nil );
end;

procedure TLogWriterWrapper.Debug( const AMsg: string; const AException: Exception );
begin
  SendToWriter( llDebug, AMsg, AException );
end;

procedure TLogWriterWrapper.Debug( const AFormat: string; const AArgs: array of const );
begin
  SendToWriter( llDebug, Format( AFormat, AArgs ), nil );
end;

procedure TLogWriterWrapper.Error( const AMsg: string );
begin
  SendToWriter( llError, AMsg, nil );
end;

procedure TLogWriterWrapper.Error( const AFormat: string; const AArgs: array of const );
begin
  SendToWriter( llError, Format( AFormat, AArgs ), nil );
end;

procedure TLogWriterWrapper.Error( const AMsg: string; const AException: Exception );
begin
  SendToWriter( llError, AMsg, AException );
end;

procedure TLogWriterWrapper.Info( const AFormat: string; const AArgs: array of const );
begin
  SendToWriter( llInfo, Format( AFormat, AArgs ), nil );
end;

procedure TLogWriterWrapper.Info( const AMsg: string );
begin
  SendToWriter( llInfo, AMsg, nil );
end;

procedure TLogWriterWrapper.Info( const AMsg: string; const AException: Exception );
begin
  SendToWriter( llInfo, AMsg, AException );
end;

function TLogWriterWrapper.IsDebugEnabled: Boolean;
begin
  Result := not( llDebug in FLogFilter );
end;

function TLogWriterWrapper.IsErrorEnabled: Boolean;
begin
  Result := not( llError in FLogFilter );
end;

function TLogWriterWrapper.IsInfoEnabled: Boolean;
begin
  Result := not( llInfo in FLogFilter );
end;

function TLogWriterWrapper.IsTraceEnabled: Boolean;
begin
  Result := not( llTrace in FLogFilter );
end;

function TLogWriterWrapper.IsWarnEnabled: Boolean;
begin
  Result := not( llWarn in FLogFilter );
end;

function TLogWriterWrapper.Name: string;
begin
  Result := FName;
end;

procedure TLogWriterWrapper.SendToWriter( const ALevel: TLogLevel; const AMessage: string; const AException: Exception );
begin
  if not( ALevel in FLogFilter )
  then
    FWriter.WriteMessage( ALevel, FName, AMessage, AException );
end;

procedure TLogWriterWrapper.Trace( const AMsg: string );
begin
  SendToWriter( llTrace, AMsg, nil );
end;

procedure TLogWriterWrapper.Trace( const AFormat: string; const AArgs: array of const );
begin
  SendToWriter( llTrace, Format( AFormat, AArgs ), nil );
end;

procedure TLogWriterWrapper.Trace( const AMsg: string; const AException: Exception );
begin
  SendToWriter( llTrace, AMsg, AException );
end;

procedure TLogWriterWrapper.Warn( const AMsg: string; const AException: Exception );
begin
  SendToWriter( llWarn, AMsg, AException );
end;

procedure TLogWriterWrapper.Warn( const AMsg: string );
begin
  SendToWriter( llWarn, AMsg, nil );
end;

procedure TLogWriterWrapper.Warn( const AFormat: string; const AArgs: array of const );
begin
  SendToWriter( llWarn, Format( AFormat, AArgs ), nil );
end;

end.

Mit einem Wrapper, kann man jetzt ganz kleine süße Log-Writer erstellen, die einfach nur IWriteLog implementieren.