Class: Synapse::UnitOfWork::UnitOfWorkListenerCollection

Inherits:
UnitOfWorkListener show all
Defined in:
lib/synapse/uow/listener_collection.rb

Overview

Represents a mechanism for notifying registered listeners in a specific order of precendence

When #on_start, #on_event_registered, #on_prepare_commit and #on_prepare_transaction_commit are invoked, the listeners will be notified the order they were added to this colleciton. When #after_commit, #on_rollback and #on_cleanup are called, listeners will be notified in the reverse order they were added to this collection.

This behavior is particularly useful for an auditing listener, which could log a commit before any listeners are allowed to do anything, and log that the commit is finished after all other listeners have finished.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ undefined 



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# File 'lib/synapse/uow/listener_collection.rb', line 16

def initialize
  @listeners = Array.new
  @logger = Logging.logger[self.class]
end

Instance Method Details

#after_commit(unit) ⇒ undefined

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 75

def after_commit(unit)
  @listeners.reverse_each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work has been committed"
    listener.after_commit unit
  end
end

#on_cleanup(unit) ⇒ undefined

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 94

def on_cleanup(unit)
  @listeners.reverse_each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work is cleaning up"

    begin
      listener.on_cleanup unit
    rescue => exception
      # Ignore this exception so that we can continue cleaning up
      backtrace = exception.backtrace.join $RS
      @logger.warn "Listener {#{listener.class}} raised exception during cleanup: " +
        "#{exception.inspect} #{backtrace}"
    end
  end
end

#on_event_registered(unit, event) ⇒ EventMessage

Parameters:

Returns:

  • (EventMessage) 


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# File 'lib/synapse/uow/listener_collection.rb', line 44

def on_event_registered(unit, event)
  @listeners.each do |listener|
    event = listener.on_event_registered unit, event
  end

  event
end

#on_prepare_commit(unit, aggregates, events) ⇒ undefined

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 56

def on_prepare_commit(unit, aggregates, events)
  @listeners.each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work is preparing for commit"
    listener.on_prepare_commit unit, aggregates, events
  end
end

#on_prepare_transaction_commit(unit, transaction) ⇒ undefined

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 66

def on_prepare_transaction_commit(unit, transaction)
  @listeners.each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work is preparing for tx commit"
    listener.on_prepare_transaction_commit unit, transaction
  end
end

#on_rollback(unit, cause = nil) ⇒ undefined

Parameters:

  • unit (UnitOfWork)
  • cause (Error) (defaults to: nil)

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 85

def on_rollback(unit, cause = nil)
  @listeners.reverse_each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work is rolling back"
    listener.on_rollback unit, cause
  end
end

#on_start(unit) ⇒ undefined

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 34

def on_start(unit)
  @listeners.each do |listener|
    @logger.debug "Notifying {#{listener.class}} that unit of work is starting"
    listener.on_start unit
  end
end

#push(listener) ⇒ undefined Also known as: <<

Pushes a unit of work listener onto the end of this collection

Parameters:

Returns:

  • (undefined) 


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# File 'lib/synapse/uow/listener_collection.rb', line 25

def push(listener)
  @logger.debug "Registering listener {#{listener.class}}"
  @listeners.push listener
end