Add Immutable Dispatcher (#13)

* Add Immutable Dispatcher

* Update Changelog

* code review fixes

.rubocop.yml

@@ -26,3 +26,6 @@ Style/TrailingCommaInArguments:
 
 Style/BlockDelimiters:
   EnforcedStyle: semantic
+
+Style/SpaceInsideHashLiteralBraces:
+  Enabled: false

.rubocop_todo.yml

@@ -1,16 +1,32 @@
 # This configuration was generated by
 # `rubocop --auto-gen-config`
-# on 2017-07-13 18:23:49 +0100 using RuboCop version 0.49.1.
+# on 2017-07-14 08:36:02 +0100 using RuboCop version 0.49.1.
 # The point is for the user to remove these configuration records
 # one by one as the offenses are removed from the code base.
 # Note that changes in the inspected code, or installation of new
 # versions of RuboCop, may require this file to be generated again.
 
-# Offense count: 4
+# Offense count: 5
 # Configuration parameters: CountComments, ExcludedMethods.
 Metrics/BlockLength:
   Max: 169
 
+# Offense count: 1
+# Configuration parameters: CountComments.
+Metrics/MethodLength:
+  Max: 11
+
+# Offense count: 1
+# Cop supports --auto-correct.
+# Configuration parameters: EnforcedStyle, SupportedStyles, ProceduralMethods, FunctionalMethods, IgnoredMethods.
+# SupportedStyles: line_count_based, semantic, braces_for_chaining
+# ProceduralMethods: benchmark, bm, bmbm, create, each_with_object, measure, new, realtime, tap, with_object
+# FunctionalMethods: let, let!, subject, watch
+# IgnoredMethods: lambda, proc, it
+Style/BlockDelimiters:
+  Exclude:
+    - 'lib/eventception/immutable_dispatcher.rb'
+
 # Offense count: 2
 # Cop supports --auto-correct.
 Style/MutableConstant:

CHANGELOG.md

@@ -3,8 +3,18 @@ All notable changes to this project will be documented in this file. This change
 
 ## [Unreleased]
 
-## 0.0.1 - 2017-07-13
+#### Adds
+
+* Your contribution here.
+* [#13](https://github.com/dcsg/eventception/pull/13): Add an Immutable Dispatcher - [@dcsg](https://github.com/dcsg).
+
+#### Changes
+
+* Your contribution here.
+* [#11](https://github.com/dcsg/eventception/pull/11): Change the license from MIT to GNU LGPLv3 - [@dcsg](https://github.com/dcsg).
+
+## v0.0.1 - 2017-07-13
 
 First release
 
-[Unreleased]: https://github.com/dcsg/eventception/compare/0.0.1...HEAD
+[Unreleased]: https://github.com/dcsg/eventception/compare/v0.0.1...HEAD

lib/eventception.rb

@@ -1,5 +1,6 @@
 require 'eventception/event'
 require 'eventception/listener_handler'
 require 'eventception/dispatcher'
+require 'eventception/immutable_dispatcher'
 require 'eventception/base_subscriber'
 require 'eventception/version'

lib/eventception/dispatcher.rb

@@ -91,6 +91,10 @@ def listeners?
 
     # Gets all listeners for the specific event sorted by descending priority.
     #
+    # == Parameters:
+    # event_name::
+    #   The name of the event
+    #
     # == Returns:
     #   The event listeners for the specific event sorted by descending priority.
     #
@@ -104,6 +108,10 @@ def listeners_for(event_name:)
 
     # Checks whether are any registered listeners for the specific event.
     #
+    # == Parameters:
+    # event_name::
+    #   The name of the event
+    #
     # == Returns:
     #   Boolean
     #
@@ -118,16 +126,34 @@ def listeners_for?(event_name:)
     #   The event to listen on
     # listener::
     #   The listener
+    # listener_method::
+    #   The name of the method to be executed in the listener
     # priority::
     #   The higher this value, the earlier an event listener will be triggered in the chain (defaults to 0)
     #
+    # == Returns:
+    #   Nil
+    #
     def add_listener(event_name:, listener:, listener_method:, priority: 0)
       event_listeners[event_name][priority] << ListenerHandler.new(listener, listener_method)
       sorted.delete(event_name)
 
       nil
     end
 
+    # Removes an event listener from the specified events.
+    #
+    # == Parameters:
+    # event_name::
+    #   The event to listen on
+    # listener::
+    #   The listener
+    # listener_method::
+    #   The name of the method to be executed in the listener
+    #
+    # == Returns:
+    #   Nil
+    #
     def remove_listener(event_name:, listener:, listener_method:)
       return unless listeners_for?(event_name: event_name)
 
@@ -140,6 +166,8 @@ def remove_listener(event_name:, listener:, listener_method:)
       end
 
       event_listeners.delete(event_name) if listener_for_event.empty?
+
+      nil
     end
 
     # Add an event subscriber.
@@ -150,6 +178,9 @@ def remove_listener(event_name:, listener:, listener_method:)
     # subscriber::
     #   The subscriber
     #
+    # == Returns:
+    #   Nil
+    #
     def add_subscriber(subscriber:)
       subscriber.subscribed_events.each do |event_subscribed|
         add_listener(
@@ -159,8 +190,21 @@ def add_subscriber(subscriber:)
           priority: event_subscribed[:priority] || 0,
         )
       end
+
+      nil
     end
 
+    # Removes an event subscriber.
+    #
+    # The subscriber is asked for all the events he is interested in and added as a listener for these events.
+    #
+    # == Parameters:
+    # subscriber::
+    #   The subscriber
+    #
+    # == Returns:
+    #   Nil
+    #
     def remove_subscriber(subscriber:)
       subscriber.subscribed_events.each do |event_subscribed|
         remove_listener(
@@ -169,6 +213,8 @@ def remove_subscriber(subscriber:)
           listener_method: event_subscribed.fetch(:listener_method),
         )
       end
+
+      nil
     end
 
     protected
@@ -183,6 +229,9 @@ def remove_subscriber(subscriber:)
     # event::
     #   The event
     #
+    # == Returns:
+    #   Nil
+    #
     def do_dispatch(listeners:, event:)
       listeners.each do |_priority, priority_listeners|
         priority_listeners.each do |listener_handler|
@@ -203,8 +252,13 @@ def do_dispatch(listeners:, event:)
     # event_name::
     #   The event name
     #
+    # == Returns:
+    #   Nil
+    #
     def sort_listeners(event_name)
       sorted[event_name] = event_listeners[event_name].sort_by { |key, _| -key }.to_h
+
+      nil
     end
   end
 end

lib/eventception/immutable_dispatcher.rb

@@ -0,0 +1,122 @@
+# frozen_string_literal: true
+
+# Eventception: A lightweight and simple Ruby Event System
+# Copyright (C) 2017 Daniel Gomes <danielcesargomes@gmail.com>
+#
+# This file is part of Eventception.
+#
+# Eventception is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Eventception is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Eventception. If not, see <http://www.gnu.org/licenses/>.
+
+# @author Daniel Gomes <danielcesargomes@gmail.com>
+module Eventception
+  class ImmutableDispatcher
+    private
+
+    attr_reader :dispatcher
+
+    public
+
+    # Creates an unmodifiable proxy for an event dispatcher.
+    #
+    # == Parameters:
+    # listeners::
+    #   Array of event listeners
+    # subscribers::
+    #   Array of event subscribers
+    #
+    # == Returns:
+    #   Nil
+    #
+    def initialize(listeners: [], subscribers: [])
+      @dispatcher = Eventception::Dispatcher.new
+
+      listeners.each do |listener|
+        dispatcher.add_listener(
+          event_name: listener.fetch(:event_name),
+          listener: listener.fetch(:listener),
+          listener_method: listener.fetch(:listener_method),
+          priority: listener.fetch(:priority, 0),
+        )
+      end
+
+      subscribers.each { |subscriber| dispatcher.add_subscriber(subscriber: subscriber) }
+
+      nil
+    end
+
+    # Dispatches an event to all registered listeners.
+    #
+    # == Parameters:
+    # event_name::
+    #   The name of the event to dispatch. The name of
+    #   the event is the name of the method that is
+    #   invoked on listeners.
+    # event::
+    #   The event to pass to the event handlers/listeners
+    #   If not supplied, an empty Event instance is created.
+    #
+    # == Returns:
+    #   The Event.
+    #
+    def dispatch(event_name:, event: Eventception::Event.new)
+      dispatcher.dispatch(event_name: event_name, event: event)
+
+      event
+    end
+
+    # Gets all listeners sorted by descending priority.
+    #
+    # == Returns:
+    #   All event listeners sorted by event_name and descending priority.
+    #
+    def listeners
+      dispatcher.listeners
+    end
+
+    # Checks whether are any registered listeners.
+    #
+    # == Returns:
+    #   Boolean
+    #
+    def listeners?
+      dispatcher.listeners?
+    end
+
+    # Gets all listeners for the specific event sorted by descending priority.
+    #
+    # == Parameters:
+    # event_name::
+    #   The name of the event
+    #
+    # == Returns:
+    #   The event listeners for the specific event sorted by descending priority.
+    #
+    def listeners_for(event_name:)
+      dispatcher.listeners_for(event_name: event_name)
+    end
+
+    # Checks whether are any registered listeners for the specific event.
+    #
+    # == Parameters:
+    # event_name::
+    #   The name of the event
+    #
+    # == Returns:
+    #   Boolean
+    #
+    def listeners_for?(event_name:)
+      dispatcher.listeners_for?(event_name: event_name)
+    end
+  end
+end

spec/eventception/immutable_dispatcher_spec.rb

@@ -0,0 +1,61 @@
+# Eventception: A lightweight and simple Ruby Event System
+# Copyright (C) 2017 Daniel Gomes <danielcesargomes@gmail.com>
+#
+# This file is part of Eventception.
+#
+# Eventception is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Eventception is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with Eventception. If not, see <http://www.gnu.org/licenses/>.
+
+require 'spec_helper'
+require 'support/listener'
+require 'support/subscriber'
+require 'support/test_event'
+
+# @author Daniel Gomes <danielcesargomes@gmail.com>
+describe Eventception::ImmutableDispatcher do
+  subject(:dispatcher) { described_class.new(listeners: listeners, subscribers: subscribers) }
+
+  let(:listener) { Eventception::Support::Listener.new }
+  let(:listener_method) { 'on_before' }
+  let(:listeners) { [] }
+  let(:subscriber) { Eventception::Support::Subscriber.new }
+  let(:subscribers) { [] }
+  let(:event_name) { :on_after }
+  let(:priority) { 0 }
+
+  describe '#initialize' do
+    context 'when one listener is provided' do
+      let(:listeners) {
+        [
+          {event_name: event_name, listener: listener, listener_method: listener_method, priority: priority},
+        ]
+      }
+
+      it 'then a listener is registered' do
+        expect(dispatcher.listeners?).to be true
+      end
+
+      it 'then it have one listener registered' do
+        expect(dispatcher.listeners.size).to eq 1
+      end
+
+      it 'then a listener for the event \'on_before\' is registered' do
+        expect(dispatcher.listeners_for?(event_name: event_name)).to be true
+      end
+
+      it 'then no listeners are registered for an invalid event name' do
+        expect(dispatcher.listeners_for?(event_name: :invalid)).to be false
+      end
+    end
+  end
+end