Class: Replicate::Emitter

Inherits:
Object
  • Object
show all
Defined in:
lib/replicate/emitter.rb

Overview

Base class for Dumper / Loader classes. Manages a list of callback listeners and dispatches to each when #emit is called.

Direct Known Subclasses

Dumper, Loader

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Emitter

Yields self to the block and calls #complete when block is finished.



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# File 'lib/replicate/emitter.rb', line 6

def initialize
  @listeners = []
  if block_given?
    yield self
    complete
  end
end

Instance Method Details

#complete ⇒ Object

Notify all listeners that processing is complete.



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# File 'lib/replicate/emitter.rb', line 50

def complete
  @listeners.each { |p| p.complete if p.respond_to?(:complete) }
end

#emit(type, id, attributes, object) ⇒ Object

Emit an object event to each listener.

Returns the object.



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# File 'lib/replicate/emitter.rb', line 44

def emit(type, id, attributes, object)
  @listeners.each { |p| p.call(type, id, attributes, object) }
  object
end

#listen(p = nil, &block) ⇒ Object

Register a listener to be called for each loaded object with the type, id, attributes, object structure. Listeners are executed in the reverse order of which they were registered. Listeners registered later modify the view of listeners registered earlier.

p - An optional Proc object. Must respond to call. block - An optional block.

Returns nothing.



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# File 'lib/replicate/emitter.rb', line 23

def listen(p=nil, &block)
  @listeners.unshift p if p
  @listeners.unshift block if block
end

#use(klass, *args, &block) ⇒ Object

Sugar for creating a listener with an object instance. Instances of the class must respond to call(type, id, attrs, object).

klass - The class to create. Must respond to new. args - Arguments to pass to new in addition to self.

Returns the object created.



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# File 'lib/replicate/emitter.rb', line 35

def use(klass, *args, &block)
  instance = klass.new(self, *args, &block)
  listen instance
  instance
end