flyweightunit1.pas

设计模式delphi版给想学delphi的朋友一个很有价值的参考

unit Flyweightunit1;


interface

uses Forms, graphics;

const
  NCHARCODES = 128;

type

  TGlyphContext = class;
  TBTree = class;

  TGlyPh = class
  protected
    constructor Create; virtual;
  public
    destructor Destroy; virtual;

    procedure Draw(aWindow: TForm; aGlyphContext: TGlyphContext); virtual;

    procedure SetFont(aFont: TFont; aGlyphContext: TGlyphContext); virtual;
    function GetFont(aGlyphContext: TGlyphContext): TFont; virtual;

    procedure First(aGlyphContext: TGlyphContext); virtual;
    procedure Next(aGlyphContext: TGlyphContext); virtual;
    function IsDone(aGlyphContext: TGlyphContext): Boolean; virtual;
    function Current(aGlyphContext: TGlyphContext): TGlyph; virtual;

    procedure Insert(aGlyph: TGlyph; aGlyphContext: TGlyphContext); virtual;
    procedure Remove(aGlyphContext: TGlyphContext); virtual;
  end;

  TCharacter = class(TGlyPh)
  private
    F_Charcode: Char;
  public
    constructor Create(C: Char); overload;

    procedure Draw(aWindow: TForm; aGlyphContext: TGlyphContext); virtual;
  end;

  TRow = class(TGlyPh)
  public
    constructor Create;
    //......
  end;

  TColumn = class(TGlyPh)
  public
    constructor Create();
    //......
  end;

  TGlyphContext = class
  private
    F_index: word;
    F_font: TBTree;
  public
    constructor Create;
    destructor Destroy; virtual;

    procedure Next(step: word = 1); virtual;
    procedure Insert(step: word = 1); virtual;

    function GetFont(): TFont; virtual;
    procedure SetFont(aFont: TFont; span: word = 1); virtual;
  end;

  TBTree = class
  public
    constructor Create;
  end;

  TGlyphFactory = class
  private
    f_character: array[1..NCHARCODES] of TCharacter;
  public
    constructor Create;
    destructor Destroy; virtual;
    function CreaterCharacter(C: Char): TCharacter; virtual;
    function CreateRow(): TRow; virtual;
    function CreateColumn(): TColumn; virtual;
    //......
  end;

implementation



constructor TGlyPh.Create;
begin
//...
end;


procedure TGlyPh.Draw(aWindow: TForm; aGlyphContext: TGlyphContext);
begin
//...
end;

procedure TGlyPh.SetFont(aFont: TFont; aGlyphContext: TGlyphContext);
begin
//...
end;

function TGlyPh.GetFont(aGlyphContext: TGlyphContext): TFont;
begin
//...
end;

procedure TGlyPh.First(aGlyphContext: TGlyphContext);
begin
//...
end;

procedure TGlyPh.Next(aGlyphContext: TGlyphContext);
begin
//...
end;

function TGlyPh.IsDone(aGlyphContext: TGlyphContext): Boolean;
begin
//...
end;

function TGlyPh.Current(aGlyphContext: TGlyphContext): TGlyph;
begin
//...
end;

procedure TGlyPh.Insert(aGlyph: TGlyph; aGlyphContext: TGlyphContext);
begin
//...
end;

procedure TGlyPh.Remove(aGlyphContext: TGlyphContext);
begin
//...
end;

destructor TGlyPh.Destroy;
begin
//...
end;

constructor TGlyphContext.Create;
begin
//....
end;

constructor TCharacter.Create(C: Char);
begin
//....
end;

procedure TCharacter.Draw(aWindow: TForm; aGlyphContext: TGlyphContext);
begin
//....
end;

destructor TGlyphContext.Destroy;
begin
//....
end;

procedure TGlyphContext.Next(step: word = 1);
begin
//....
end;

procedure TGlyphContext.Insert(step: word = 1);
begin
//....
end;

function TGlyphContext.GetFont(): TFont;
begin
//....
end;

procedure TGlyphContext.SetFont(aFont: TFont; span: word = 1);
begin
//....
end;

constructor TBTree.Create;
begin
//....
end;

constructor TGlyphFactory.Create;
var
  i: word;
begin
  for i := 0 to NCHARCODES - 1 do
    f_character[i] := nil;
//....
end;

destructor TGlyphFactory.Destroy;
begin
//....
end;

function TGlyphFactory.CreaterCharacter(C: Char): TCharacter;
var
  i, j: word;
  isExist: Boolean;
begin
  isExist := false;
  for i := 0 to NCHARCODES - 1 do
  begin
    if f_character[i].F_Charcode = c then
    begin
      isExist := true;
      j := i;
      Exit;
    end
    else
      if f_character[i] = nil then
      begin
        j := i;
        Exit;
      end;
  end;
  if not isExist then
    f_character[j] := TCharacter.Create(c);
  Result := f_character[j];
//....
end;

function TGlyphFactory.CreateRow(): TRow;
begin
  Result := TRow.Create;
//....
end;

function TGlyphFactory.CreateColumn(): TColumn;
begin
  Result := TColumn.Create;
//....
end;

constructor TRow.Create;
begin
//....
end;

constructor TColumn.Create;
begin
//....
end;

end.