才开始学模式,自己写的一个工厂方法,大家看看,看谁能用拿去用吧

Question

就是太长了,我分几次贴吧,高手给指导指导unit Cls_DataFactory;interface{  本单元定义了系统配置类、ADO数据访问抽象类，基于ADO的 ms sql server
   实体类，以及数据访问工厂，其中ADO数据访问类是一个产品族，在工厂方法
   的基础上可以扩展如： acces，oracle等等能以ADO进行访问的产品。
   注意：数据访问抽象类接口仅仅支持SQL
 }uses db, adodb, SysUtils, Classes;type   {系统配置类}
   TConfig = class(TObject)
   private
     Fallname: string;
     Fsimplename: string;
     Ftelephone: string;
     Faddress: string;
     Fhomepage: string;
     Femail: string;
     Fsvrname: string;
     Fdatabase: string;
     Fuser: string;
     Fpassword: string;
     function getallname: string;
     procedure setallname(value: string);
     function getsimplename: string;
     procedure setsimplename(value: string);
     function gettelephone: string;
     procedure settelephone(value: string);
     function getaddress: string;
     procedure setaddress(value: string);
     function gethomepage: string;
     procedure sethomepage(value: string);
     function getemail: string;
     procedure setemail(value: string);
     function getsvrname: string;
     procedure setsvrname(value: string);
     function getdatabase: string;
     procedure setdatabase(value: string);
     function getuser: string;
     procedure setuser(value: string);
     function getpassword: string;
     procedure setpassword(value: string);
     procedure loadconfig(fn: string);
   public
     constructor create;
     procedure saveconfig(fn: string);
     property allname: string read getallname write setallname;
     property simplename: string read getsimplename write setsimplename;
     property telephone: string read gettelephone write settelephone;
     property address: string read getaddress write setaddress;
     property homepage: string read gethomepage write sethomepage;
     property email: string read getemail write setemail;
     property svrname: string read getsvrname write setsvrname;
     property database: string read getdatabase write setdatabase;
     property user: string read getuser write setuser;
     property password: string read getpassword write setpassword;
   end;   {抽象数据访问类}
   TAbsAdoManager = class(Tdatamodule)
   protected
     FConfig: TConfig;
     Connector: TAdoConnection;
     function getconfig: TConfig;  virtual; abstract;
     procedure setconfig(value: TConfig); virtual; abstract;
     function getconnstring: string; virtual; abstract;
   public
     function  StartConnection: boolean; virtual; abstract;
     procedure EndConnection; virtual; abstract;
     function GetDbList: Tstrings; virtual; abstract;
     procedure ExecuteSQL(SQL: string); virtual; abstract;
     function  GetDataSet(SQL: string): TDataSet; virtual; abstract;
     property  Config: TConfig read getconfig write setconfig;
   end;   TAdoSqlManager = class(TAbsAdoManager)
   protected
     FConfig: TConfig;
     Connector: TAdoConnection;
     function getconfig: TConfig; override;
     procedure setconfig(value: TConfig); override;
     function getconnstring: string; override;
   public
     constructor Create(AOwner: TComponent); override;
     destructor Destory;
     function  StartConnection: boolean; override;
     procedure EndConnection; override;
     function GetDbList: Tstrings; override;
     procedure ExecuteSQL(SQL: string); override;
     function  GetDataSet(SQL: string): TDataSet; override;
     property  Config: TConfig read getconfig write setconfig;
   end;   { 工厂方法 }
   TDataFactory = class(TObject)
   public
     function CreateAdoSqlManager(AOwner: TComponent): TAdoSqlManager;
     //下面尚未定义的数据访问类的工厂方法
     //function CreateAdoAccessManager(AOwner: TComponent): TAdoSqlManager;
     //function CreateAdoOracleManager(AOwner: TComponent): TAdoSqlManager;
   end;

Answer 1

implementationuses  inifiles;{ 配置文件中的口令加解密}function Encrypt(value: string): string;
begin
  result:= value;
end;function Decrypt(value: string): string;
begin
  result:= value;
end;{ Sql server 访问类实现 }constructor TAdoSqlManager.Create(AOwner: TComponent);
begin
  inherited;
  try
    FConfig:= TConfig.create;
    Connector:= TAdoConnection.Create(AOwner);
  except
  end;
end;
function TAdoSqlManager.StartConnection: boolean;
begin
  result:= false;
  try
    EndConnection;
    if not Connector.Connected then
    begin
      Connector.ConnectionString:= getconnstring;
    end;
    Connector.Open;
    result:= Connector.Connected;
  except
    exit;
  end;
end;procedure TAdoSqlManager.EndConnection;
begin
  inherited;
  Connector.Close;
end;procedure TAdoSqlManager.ExecuteSQL(SQL: string);
var
  TempCommand: TAdoCommand;
begin
  inherited;
  TempCommand:= TAdoCommand.Create(nil);
  try
    TempCommand.CommandText:= SQL;
    Tempcommand.Execute;
  finally
    TempCommand.Free;
  end;
end;function TAdoSqlManager.GetDataSet(SQL: string): TDataSet;
var
  TempDataSet: TAdoquery;
begin
  TempDataSet:= TAdoquery.Create(nil);
  try
    TempDataSet.Connection:= Connector;
    TempDataSet.SQL.Add(SQL);
    TempDataSet.Open;
  except
  end;
  result:= TempDataSet;
end;destructor TAdoSqlManager.Destory;
begin
  Connector.Free;
  inherited;
end;function TAdoSqlManager.getconfig: TConfig;
begin
  result:= Fconfig;
end;procedure TAdoSqlManager.setconfig(value: TConfig);
begin
 Fconfig:= value;
end;function TAdoSqlManager.GetDbList: Tstrings;
var
  dblist: Tstrings;
  TempDataSet: TAdoquery;
begin
  dblist:= Tstringlist.Create;
  TempDataSet:= TAdoquery.Create(nil);
  try
    TempDataSet.Connection:= Connector;
    TempDataSet.SQL.Add('exec sp_databases');
    TempDataSet.Open;
    while not TempDataSet.Eof do
    begin
      dblist.Add(TempDataSet.fieldbyname('DATABASE NAME').AsString);
      TempDataSet.Next;
    end;
  finally
    TempDataSet.Free;
  end;
  result:= dblist;
end;

Answer 2

{ 系统配置类实现 }constructor TConfig.create;
begin
  try
   loadconfig('config.ini');
  except
  end;
end;function TConfig.getaddress: string;
begin
  result:= Faddress;
end;function TConfig.getallname: string;
begin
  result:= Fallname;
end;function TConfig.getdatabase: string;
begin
  result:= Fdatabase;
end;function TConfig.getemail: string;
begin
  result:= Femail;
end;function TConfig.gethomepage: string;
begin
  result:= Fhomepage;
end;function TConfig.getpassword: string;
begin
  result:= fpassword;
end;function TConfig.getsimplename: string;
begin
  result:= Fsimplename;
end;function TConfig.getsvrname: string;
begin
  result:= fsvrname;
end;function TConfig.gettelephone: string;
begin
  result:= Ftelephone;
end;function TConfig.getuser: string;
begin
  result:= fuser;
end;function TAdoSqlManager.getconnstring: string;
begin
  result:= 'Provider=SQLOLEDB.1;';
  result:= result + 'Persist Security Info=False;';
  result:= result + 'Initial Catalog=' + FConfig.Fdatabase + ';';
  result:= result + 'User Id=' + FConfig.FUser + ';';
  result:= result + 'Password=' + FConfig.Fpassword + ';';
  result:= result + 'Data Source=' + FConfig.Fsvrname;
end;procedure TConfig.loadconfig(fn: string);
var
  inifile: Tinifile;
begin
  inifile:= Tinifile.Create(fn);
  try
    Fallname:= inifile.ReadString('Application','allname','');
    Fsimplename:= inifile.ReadString('Application','simplename','');
    Ftelephone:= inifile.ReadString('Application','telephone','');
    Faddress:= inifile.ReadString('Application','address','');
    Fhomepage:= inifile.ReadString('Application','homepage','');
    Femail:= inifile.ReadString('Application','email','');
    Fsvrname:= inifile.ReadString('ADO','svrname','127.0.0.1');
    Fdatabase:= inifile.ReadString('ADO','database','master');
    Fuser:= inifile.ReadString('ADO','user','guest');
    Fpassword:= Decrypt(inifile.ReadString('ADO','password',''));
  finally
    inifile.Free;
  end;
end;procedure TConfig.saveconfig(fn: string);
var
  inifile: Tinifile;
begin
  inifile:= Tinifile.Create(fn);
  try
    inifile.WriteString('Application','allname',Fallname);
    inifile.WriteString('Application','simplename',Fsimplename);
    inifile.WriteString('Application','telephone',Ftelephone);
    inifile.WriteString('Application','address',Faddress);
    inifile.WriteString('Application','homepage',Fhomepage);
    inifile.WriteString('Application','email',Femail);
    inifile.WriteString('ADO','svrname',Fsvrname);
    inifile.WriteString('ADO','database',Fdatabase);
    inifile.WriteString('ADO','user',Fuser);
    inifile.WriteString('ADO','password',Encrypt(Fpassword));
  finally
    inifile.Free;
  end;
end;procedure TConfig.setaddress(value: string);
begin
  Faddress:= value;
end;procedure TConfig.setallname(value: string);
begin
  Fallname:= value;
end;procedure TConfig.setdatabase(value: string);
begin
  Fdatabase:= value;
end;procedure TConfig.setemail(value: string);
begin
  Femail:= value;
end;procedure TConfig.sethomepage(value: string);
begin
  Fhomepage:= value;
end;procedure TConfig.setpassword(value: string);
begin
 Fpassword:= value;
end;procedure TConfig.setsimplename(value: string);
begin
  Fsimplename:= value;
end;procedure TConfig.setsvrname(value: string);
begin
  Fsvrname:= value;
end;procedure TConfig.settelephone(value: string);
begin
  Ftelephone:= value;
end;procedure TConfig.setuser(value: string);
begin
  Fuser:= value;
end;{ 工厂实现 }function TDataFactory.CreateAdoSqlManager(AOwner: TComponent): TAdoSqlManager;
begin
  result:= TAdoSqlManager.Create(AOwner);
end;end.

Answer 3

{ 抽象工厂 }
   TAbsDataFactory = class(TObject)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager;
   end;   TAdoSqlFactory = class(TAbsDataFactory)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager;
   end;

Answer 4

只看这一个就够了：   TDataFactory = class(TObject)
   public
     function CreateAdoSqlManager(AOwner: TComponent): TAdoSqlManager;
   end;毛病一，你声明的抽象类TAbsAdoManager，不直接做返回值，却用了TAdoSqlManager。这是何故？而后面搞了一个TAdoSqlFactory多余的东西来用。又是何故？一个工厂模式别名叫虚构造机。毛病二，工厂模式，也要管调用的是哪个构造方法。你现在有一个构造方法，用一个类来管理，然后针对每个构造方法派生出许多管理类。但是有N个你怎么办？难道调用N个方法？？？N个工厂类，生成N个管理类。尽管你这个例子中，数据连接是屈指可数的，但不用忘了，它叫：设计模式。是通用的。要对接口编程，不能对实现编程！工厂有一个，产品可以有N个。但是你现在的状况有N个工厂来制造N个对应的产品。这就算工厂模式？好了，其他的我不再多说了。再看看，再学学…… 问一下：你看了GOF的书了吗？

Answer 5

没有所谓的TAdoSqlFactory，没有所谓的TAdoAccessFactory，没有所谓的TAdoOracleFactory只有一个！那就是TAdoFactory。

Answer 6

重写了一下，看看还有毛病没有？
 {抽象数据访问类}
   TAbsAdoManager = class(Tdatamodule)
   public
     function  StartConnection: boolean; virtual; abstract;
     procedure EndConnection; virtual; abstract;
     function GetDbList: Tstrings; virtual; abstract;
     procedure ExecuteSQL(SQL: string); virtual; abstract;
     function  GetDataSet(SQL: string): TDataSet; virtual; abstract;
   end;   TAdoSqlManager = class(TAbsAdoManager)
   private
     Connector: TAdoConnection;
     function getconnstring: string;
   public
     constructor Create(AOwner: TComponent); override;
     destructor Destory;
     function  StartConnection: boolean; override;
     procedure EndConnection; override;
     function GetDbList: Tstrings; override;
     procedure ExecuteSQL(SQL: string); override;
     function  GetDataSet(SQL: string): TDataSet; override;
   end;   { 抽象工厂 }
   TAbsDataFactory = class(TObject)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager; virtual; abstract;
   end;   TAdoSqlFactory = class(TAbsDataFactory)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager; override;
   end;   //下面定义尚未实现的数据访问类的工厂方法
   {
   TAdoAccessFactory = class(TAbsDataFactory)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager; override;
   end;   TAdoOracleDataFactory = class(TAbsDataFactory)
   public
     function CreateManager(AOwner: TComponent): TAbsAdoManager; override;
   end;
   }

Answer 7

另外，提醒你。你的virtual; abstract;别随便用。谨慎一些。

Answer 8

为什么现在的高手的这么吝啬，哎...
不过，先谢谢了 reallike(爱翔)