Domain Driven Recruitment Pipeline

recruitment_pipeline.rb

class RecruitmentPipeline  
end

# Stage is a progression or step on a candidate's job application.
# It represents the state the application is in and offers several
# statistic on the effectiveness of consultant at this stage.
#
# For example, Stage 1 might be AppliedStage, or NewStage
# depending on whether candidate applied himself or consultant
# selected him.
class Stage
  include StateMachine

  def initialize(pipeline)
    @pipeline = pipeline
  end

  def log
    candidate = pipeline.candidate
    consultant = pipeline.consultant
    message = i18n(:applied, candidate, consultant)
    write_to_log_db(message)
  end

  def duration
    previous_stage.timestamp - timestamp
  end

  def previous_stage
    # Using a nil safe object to find out the previous
    # stage. If nil, calling #timestamp will be no-op
  end

  def next_stage
    # why not? since we have previous stage, we might as well
    # present what's the next stage for this particular stage
  end

  def timestamp
    # snip
  end

  private

  def write_to_log_db
    # snip
  end
end

class AppliedStage < Stage
  common_name :applied
  transition_to :reviewed
end

class SubmittedStage < Stage
  common_name :submitted
  transition_to :rejected, :interview, :offered
end

@pipeline.stages
@pipeline.stages[:applied]
@pipeline.stages[:submitted].duration # => 3 hours, which tells us that consultant took 3 hours to submit application