[Rock-dev] improvement TaskContext.get

[Alexander Duda]

TaskContext.get(task_name) has some drawbacks for the following use
case:

Someone is pressing on a button and wants to call an operation on a
specific task. The GUI can be started before the deployments are started
and therefore it must be checked if the task is reachable every time the
button is pressed. 

The current implementation checks the nameservice for the task 
and raises an error if the task cannot be found. It would be better if 
the method would be doing something like:

      @cache_task_context ||= Hase.new
      task = @cache_task_context[task_name]
      if(!task || !task.readable?)
        begin
          task = Orocos::TaskContext.get task_name
          @cache_task_context[task_name] = task
        rescue CORBA::ComError 
          @cache_task_context[task_name] = nil
          task = nil
        end
      end
      task

Usage:

def button
	task = Orocos::TaskContext.get 'my_task'
	task.myOperation() if task
end

Currently I have a helper method for this in Vizkit.rb but I think it
would be nice to move it into the method get

thoughts?

Alex

-- 
Dipl.-Ing. Alexander Duda 
Unterwasserrobotik

DFKI Bremen
Robotics Innovation Center
Robert-Hooke-Straße 5
28359 Bremen, Germany

Phone: +49 (0)421 178-456620
Fax:   +49 (0)421 178-454150
E-Mail: alexander.duda at dfki.de

Weitere Informationen: http://www.dfki.de/robotik
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