Toolcase

A module to convert a class in a Toolcase of handlers.

Inspired in an implementation of a Strategy pattern mixed with an Abstract Factory. Add this module to a class to have the ability of register handlers as Strategies, and then search/select them as a Factory.

Add this line to your application's Gemfile:

gem 'toolcase'

And then execute:

$ bundle install

Extend a class to convert it into a strategy factory:

class Factory
  extend Toolcase::Registry

  register Linux
  register Windows
  register MacOS
  register { |it| it.do_something }

  default InvalidOS
end

The register method adds an object to the registry. It can be a block or proc.

A default object can be assigned using the default method. The default object, if present, will be returned by default in any search that no object is found. This applies for the find_by and [] methods.

register methods has the following options:

class Factory
  extend Toolcase::Registry

  register Linux, tag: :OS                # Registries can be classified with a tag.
  register OtherStuff, id: :otherstuff    # An item can have an identifier.
end

An object can be located in different ways:

# By id.
Factory[:otherstuff]

# Using the find_by function, which will search through all registries.
Factory.find_by { |object| object.handle?(*args) }

# Search only through items with a specific tag.
Factory.find_by(:OS) { |object| object.handle?(*args) }

# Look up if an specific object belongs to the registry.
Factory.include?(object)

# Look up if an specific object is present in a specific tag.
Factory.include?(object, :OS)

# Get all registries.
Factory.registries

# Get all tagged registries.
Factory.registries(:OS)

If another class inherits from the Factory, its registries are inherited too. An useful use case is a validator registry, with common validators in base classes, and specific validators in concrete classes.

class BaseRegistry
  extend Toolcase::Registry

  register BaseValidator
  register NonEmpty
end

class SpecificRegistry < BaseRegistry
  register SpecificValidator
end

SpecificRegistry.size   # Returns 3.

An item can be replaced or removed using the item id or the item directly.

Factory.replace(:linux, Ubuntu)
Factory.replace(Linux, Ubuntu)
Factory.remove(:windows)
Factory.remove(Windows)

A registry can be cleared completely or by tag.

Factory.clear(:linux)
Factory.clear

After checking out the repo, run bin/setup to install dependencies. Then, run rake test to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and the created tag, and push the .gem file to rubygems.org.

Bug reports and pull requests are welcome on GitHub at https://github.com/enchf/toolcase.

The gem is available as open source under the terms of the MIT License.