unit UExporter;
{ ============================================= }
interface
{ ============================================= }
type  TExporter = class  
public
    class function ExporterName: string; virtual; abstract;
    procedure BeginExport; virtual; abstract;
    procedure ExportNextString(const s:string); virtual; abstract;
    procedure EndExport; virtual; abstract;  end;
{ ============================================= }
implementation
{ ============================================= }
end

unit UClassManager;
{ ============================================= }
interface
{ ============================================= }
uses  Classes;  
type
  TClassManager = class(TList);

function ClassManager: TClassManager;
{ ============================================= }
implementation
{ ============================================= }
var  Manager: TClassManager;
function ClassManager: TClassManager;
begin  
	Result := Manager;
end;
{ ============================================= }
initialization
{ ============================================= }
Manager := TClassManager.Create;
{ ============================================= }
finalization
{ ============================================= }
Manager.Free;
end

unit UPlainFileExporter;
{ ============================================= }
interface
{ ============================================= }
uses  Classes, UExporter;
type
  TPlainFileExporter = class(TExporter)  
	private    F: TextFile;  
	public
    	class function ExporterName: string; override;
    	procedure BeginExport; override;
    	procedure ExportNextString(const s:string); override;
    	procedure EndExport; override;  
	end;
{ ============================================= }	
implementation
{ ============================================= }
uses
  Dialogs, SysUtils, UClassManager;{ TPlainFileExporter }
procedure TPlainFileExporter.BeginExport;
var  OpenDialog : TOpenDialog;
begin
	OpenDialog := TOpenDialog.Create(nil);  
	try    if OpenDialog.Execute then
	begin      
		AssignFile(F,OpenDialog.FileName);      
		Rewrite(F);    
	end
	else      
		Abort;  
	finally    
		OpenDialog.Free;  
	end;
end;

procedure TPlainFileExporter.EndExport;
begin  
	CloseFile(F);
end;

class function TPlainFileExporter.ExporterName: string;
begin
  Result := 'Экспорт в текстовый файл';
end;

procedure TPlainFileExporter.ExportNextString(const s: string);
begin
  WriteLn(F, s);
end;
{ ============================================= }
initialization
{ ============================================= }
ClassManager.Add(TPlainFileExporter);
{ ============================================= }
finalization
{ ============================================= }
ClassManager.Remove(TPlainFileExporter);
end

procedure TMainForm.RefreshPluginList;
var  i : Integer;
begin
	PluginsBox.Items.Clear;  
	for i := 0 to ClassManager.Count - 1 do
		PluginsBox.Items.Add(TExporterClass(ClassManager[i]).ExporterName);
end;

procedure TMainForm.LoadBtnClick(Sender: TObject);
begin
  PluginModule := LoadPackage(ExtractFilePath(ParamStr(0)) + 'HTMLPluginProject.bpl');
  RefreshPluginList;
end;

procedure TMainForm.UnloadBtnClick(Sender: TObject);begin
  UnloadPackage(PluginModule);  RefreshPluginList;end;

procedure TMainForm.ExportBtnClick(Sender: TObject);
var	ExporterClass: TClass;
 	Exporter: TExporter;  
	i: Integer;
begin  
	if PluginsBox.ItemIndex < 0 then 
		Exit;      

	ExporterClass := ClassManager[PluginsBox.ItemIndex];
	Exporter := TExporter(ExporterClass.Create);  

	try    Exporter.BeginExport;
    	try      
			for i := 0 to StringsBox.Lines.Count - 1 do
				Exporter.ExportNextString(StringsBox.Lines[i]);    
		finally
			Exporter.EndExport    
		end;  
	finally    
		Exporter.Free;  
	end;
end;