Observatory
Overview
Description
Observatory is a simple Ruby gem that implements the observer design pattern to facilitate loosely coupled communication between objects in your program. It allows one object to publish an event, and others to respond to that.
Using Observatory you can apply filters to method arguments, respond to events in your program or dynamically inject new functionality.
What's new?
See HISTORY for a list of changes per version.
Usage
Installation
Observatory is distributed as a Ruby gem, so installation is simple:
$ gem install observatory
Then, you only need to load it in your program using Bundler or a manual require, like so:
require 'observatory'
Quick start
For full documentation refer to the inline API docs (which you can generate using the yard
rake task). A quick overview:
class Post include Observatory::Observable attr_reader :dispatcher, :title def initialize(title, dispatcher) @title = title @dispatcher = dispatcher end def publish notify 'post.publish', :title => title end def title filter('post.title', @title).return_value end end class Logger include Observatory::Observer def initialize(dispatcher) @dispatcher = dispatcher end observe 'post.publish' def log(event) "Post published: #{event[:title]}" end end dispatcher = Observatory::Dispatcher.new dispatcher.connect('post.title') do |event, title| "Title: #{title}" end p = Post.new('foo', dispatcher) l = Logger.new(dispatcher) p.publish # => Outputs: 'Post published: Title: foo'
More information
To Do
- Complete unit tests for mixins.
Note on Patches/Pull Requests
- Fork the project.
- Make your feature addition or bug fix.
- Add tests for it. This is important so I don't break it in a future version unintentionally.
- Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)
- Send me a pull request. Bonus points for topic branches.
Credits
By Arjan van der Gaag arjan@arjanvandergaag.nl. Based on the Event Dispatcher Symfonoy Component.
License
Observatory is released under the same license as Ruby. See LICENSE for more information.