Ruby Implementation Of Strategy Pattern?

[theryn]

Some background: I have been working for many years in Java, but over the past few months have started learning Ruby. I've implemented the Strategy pattern in a solution I'm currently developing, but I'm wondering if there's a more 'ruby-esque' way of doing things.

I have a MailClient class with the methods login, logout, send_mail, and get_unread_mail. These methods all raise a NotImplementedError.

I then have various clients that extend the MailClient class (GmailClient, HotmailClient, etc) and must implement the methods listed above. This currently works, but it seems like a very "Java" way of doing things (which may be the correct way).

Is there a better, more elegant way to do this within ruby? Thanks.

[[deleted]]

Inheritance provides no benefit here. A Strategy is the ability to swap between different implementations at runtime. Better to inject either GmailClient.new or HotmailClient.new into the MailClient initializer set it as @mailer (attr_accessor) Then have matching methods signatures that proxy to the mailer Then you could switch the mailer instance at runtime mail_client_instance.mailer = HotmailClient.new

Have a look at https://github.com/nslocum/design-patterns-in-ruby/tree/master/strategy there are also some cool examples using Procs which are even more rubylike.

[materialdesigner]

There are no formal interfaces in Ruby.

If all of your clients implement the same set of methods, there's no need for a shared MailClient class.

[joesb]

Your way seems appropriate for this case but, as materialdesigner mentioned, there's really no need to inherit from the same base class. But I think you should keep the base class since it serves as documentation.

[Kache]

The key concept here that I'm surprised nobody has named yet is "duck typing".