配置解析器 - 静态与否？

Question

Imagine a strategy whereby you might want parsers for several formats of config file, say INI, XML and YAML for example. Parsing these will result in an instance of a common class say 'Config_Data'.

My thoughts are that as the parser has a very simple mandate, and no state that I can see, it is best implemented as a static class, so you could employ the following:

Parser_Ini::parse(...);
Parser_Xml::parse(...);
...

This doesn't feel entirely correct to me as of course these static classes can't implement an interface etc, but they would seem to make good sense.

I would be interested to know your thoughts on the matter :).

Thanks, James

Answer 1

Creating static classes have a lot of drawbacks, and I don't see what you gain from it, other than a feeling of convenience, which I find is misleading you.

If you do the classes as regular instance classes, and implement an interface, you will have the freedom of changing implementation on the fly.

The classes that depend on your parser can just take an implementation of your interface as a parameter, and you can thereby inject whatever parser-type you need on that class.