CSC/ECE 517 Fall 2010/ch3 3d mr

Aspect-oriented programming and AspectR

AspectR is a very useful Ruby module, but it is not easy to find documentation on it that is appropriate for students taking this class. Find, or construct, documentation that explains what it does without presuming previous knowledge of AspectJ, that describes many or all methods of the module and how they work. Also find or produce an easy-to-understand example that does not involve logging. Show how the example would be implemented in AspectJ and AspectR.

Methods

• add_advice (AspectR::Aspect)

• all_classes (AspectR)

• disable_advice_dispatching (AspectR::Aspect)

• dispatch? (AspectR::Aspect)

• get_methods (AspectR::Aspect)

• new (AspectR::Aspect)

• prepare (AspectR::Aspect)

• remove_advice (AspectR::Aspect)

• unwrap (AspectR::Aspect)

• wrap (AspectR::Aspect)

• wrap_classes (AspectR)

• wrap_with_code (AspectR::Aspect)

• wrappable? (AspectR::Aspect)

Example

The code below implements a code profiler to measure the duration of method calls.

AspectR

require aspectr.rb
include AspectR

class Profiler < Aspect
  def method_start(method, object, exitstatus, *args)
    @begin = Time.now
  end
  def method_end(method, object, exitstatus, *args)
    timeElapsed = Time.now - @begin
    puts "#{object.class}.#{method} took #{timeElapsed} secs"
  end
end

#if $0 == __FILE__
  class SomeClass
    def some_method
      puts "hello"
      sleep 5
    end
  end

  Profiler.new.wrap(SomeClass, :method_start, :method_end, /some/)
  SomeClass.new.some_method
#end