[boost] Re: Any interest in a generic pluggable factory class?

From: Bohdan (gejrlaug_at_[hidden])
Date: 2003-08-30 02:39:52

If your solution is generic i'm interested.
Is it possible to look at code ?
BTW, Your library may correlate with expected serialization library.

regards,
bohdan

"Rob & Lori" <Rob.Lori_at_[hidden]> wrote in message
news:3F4E81BA.1040902_at_buckeye-express.com...
> For those of you who are unfamiliar with pluggable factories, I suggest
> reading the following C++ Report article:
> http://www.adtmag.com/joop/crarticle.asp?ID=1520
>
> To give a brief description, pluggable factories allow programmers to
> create instances of a class by just referencing a class identifier.
> Pluggable factories are extremely helpful anytime you wish to construct
> a class based on outside input such as reconstructing classes sent over
> a TCP/IP stream, constructing classes read from a file, constructing
> classes to execute commands read in from a scripting/macro language, etc.
>
> The pluggable factory has these features:
> 1. Classes can be registered and unregistered dynamically
> 2. Any data type that implements the assignment and comparison operators
> can be used as a class identifier type
> 3. Classes can be registered with multiple class identifier's, even if
> they are of different data types
> 3. Instances of new classes can be created simply by passing the correct
> class identifier
> 4. The class identifier value can be retrieved for any given registered
> class
>
> Let me know what you guys think.
>
> Rob Geiman
>
>
> Example usage:
>
> typedef ObjectFactory<Command> CommandFactory;
>
> static std::string open_file_command = "open_file";
> static std::string close_file_command = "close_file";
> static std::string find_text_command = "find_text";
>
> ...
>
> CommandFactory::Register<OpenFileCommand>(open_file_command);
> CommandFactory::Register<CloseFileCommand>(close_file_command);
> CommandFactory::Register<FindTextCommand>(find_text_command);
>
> ...
>
> // Loop through macro stream, reading in and executing all commands
> std::string cmd_text;
>
> while (macro_stream.good() && !macro_stream.eof())
> {
>     macro_stream >> cmd_text;
>
>     Command *cmd = CommandFactory::Create(cmd_text);
>
>     if (cmd)
>     {
>         cmd->ExtractParams(macro_stream);
>         cmd->Execute();
>     }
>     else
>     {
>         std::cout << "Unknown command: " << cmd_text << std::endl;
>     }
> }
>
> ...
>
> std::cout << "Class OpenFileCommand registered with id " <<
> CommandFactory::GetClassId<OpenFileCommand, string>() << std::endl;
> std::cout << "Class CloseFileCommand registered with id " <<
> CommandFactory::GetClassId<OpenFileCommand, string>() << std::endl;
> std::cout << "Class FindTextCommand registered with id " <<
> CommandFactory::GetClassId<OpenFileCommand, string>() << std::endl;
>
> ...
>
> CommandFactory::Unregister(open_file_command);
> CommandFactory::Unregister(close_file_command);
> CommandFactory::Unregister(find_text_command);
>
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