Class: Synco::Controller

Inherits:
Object
  • Object
show all
Defined in:
lib/synco/controller.rb

Overview

Basic event handling and delegation.

Direct Known Subclasses

Directory, Method, Script, Server

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Controller

Returns a new instance of Controller.



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# File 'lib/synco/controller.rb', line 36

def initialize
  @events = Hash.new{|hash,key| hash[key] = Array.new}
  @aborted = false
end

Instance Attribute Details

#events ⇒ Object (readonly)

Returns the value of attribute events.



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# File 'lib/synco/controller.rb', line 47

def events
  @events
end

Class Method Details

.build(*arguments, **options, &block) ⇒ Object 



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# File 'lib/synco/controller.rb', line 24

def self.build(*arguments, **options, &block)
  controller = self.new(*arguments, **options)
  
  if block_given?
    yield(controller)
  end
  
  controller.freeze
  
  return controller
end

Instance Method Details

#abort!(persistent = false) ⇒ Object

Abort the current event handler. Aborting an event handler persistently implies that in the future it will still be aborted; thus calling #try will have no effect.



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# File 'lib/synco/controller.rb', line 106

def abort!(persistent = false)
  @aborted = true if persistent
  
  throw abort_name
end

#fire(event, *args) ⇒ Object

Fire an event which calls all registered event handlers in the order they were defined. The first argument is used to #instance_eval any handlers.



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# File 'lib/synco/controller.rb', line 56

def fire(event, *args)
  return false unless @events.key?(event)
  
  handled = false
  
  scope = args.shift
  
  @events[event].each do |handler|
    handled = true

    if scope
      scope.instance_exec(*args, &handler)
    else
      handler.call
    end
  end
  
  return handled
end

#freeze ⇒ Object 



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# File 'lib/synco/controller.rb', line 41

def freeze
  @events.freeze
  
  super
end

#on(event, &block) ⇒ Object

Register an event handler which may be triggered when an event is fired.



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# File 'lib/synco/controller.rb', line 50

def on(event, &block)
  @events[event] << block
end

#try(*arguments) ⇒ Object

Try executing a given block of code and fire appropriate events.

The sequence of events (registered via #on) are as follows:

:prepare

Fired before the block is executed. May call #abort! to cancel execution.

:success

Fired after the block of code has executed without raising an exception.

:failure

Fired if an exception is thrown during normal execution.

:finish

Fired at the end of execution regardless of failure.

If #abort! has been called in the past, this function returns immediately.



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# File 'lib/synco/controller.rb', line 85

def try(*arguments)
  return if @aborted
  
  begin
    catch(abort_name) do
      fire(:prepare, *arguments)
      
      yield
      
      fire(:success, *arguments)
    end
  rescue Exception => exception
    # Propagage the exception unless it was handled in some specific way.
    raise unless fire(:failure, *arguments, exception)
  ensure
    fire(:finish, *arguments)
  end
end