[openrtm-users 02821] Re: component is_activated() via service interface

[György Persa]

Dear Ando-san,

thank you for your very detailed answer!
I've tried out the methods you suggested and successfully solved my problem
by using "_non_existent()" function, based on your example!

Best regards,

György Persa
*Software engineer*
Institute for Computer Science and Control
Hungarian Academy of Sciences
3D Internet-based Control and Communications Research Laboratory / 3DICC
*Project VirCA* (www.virca.hu)


On Wed, Jun 26, 2013 at 5:37 AM, Ando Noriaki <n-ando ＠ aist.go.jp> wrote:

> Hello,
>
> At first, basic three states (inactive, active and error) belong
> to ExecutionContext.  It means that an RTC A can be in Inactive
> state on an ExecutionContext X while the RTC A might be in Active
> state on an ExecutionContext Y.
>
> But usually an RTC is associated with only one its own
> ExecutionContext with ec_id=0.
>
> If you can get the object reference of an RTC, you also can get
> its ExecutionContextService object(s).  So an operation
> RTC::ExecutionContext::get_component_state(in LightweightRTObject
> comp ) is available.
>
>
> http://www.openrtm.org/OpenRTM-aist/documents/IDLReference-en/interfaceRTC_1_1ExecutionContext.html#51a0396327ec0bab96f06a246032fc84
>
> This is an example code.
>
>  // -*- C++ -*-
>  RTC::RTObject_var rtobj = obtaining object reference of an RTC anyway;
>  RTC::ExecutionContextServiceList_var ecs = rtobj->get_owned_contexts();
>  // ecs[0] is default context
>  LifeCycleState state = ecs[0]->get_component_state(rtobj);
>  // Now you can get state of the RTC :-)
>
> But, the RTC might have one or more ExecutionContexts. In that
> case, you have to investigate states of the RTC in each
> ExecutionContext.
>
> You can also know the state of an RTC through service ports if
> the RTC has provided interfaces (provider) on it.
> RTC::CorbaComsumer<> can be three states: nil, inactive, active.
>
>
> http://www.openrtm.org/OpenRTM-aist/documents/current/cxx/classreference_en/classRTC_1_1CorbaPort.html#a1b9efe804a293b2c38a9cbe3b5ba54a0
>
> - nil: Any object references are not assigned to this placeholder.
> - active: an object reference is assigned and activated.
> - inactive: an object reference is assigned but inactivated.
>
> You can investigate whether the CorbaConsumer is nil by using
> CORBA::is_nil().  Active or inactive object state can be
> obtained by using "_non_existent()" function.
>
> This knowledge can be obtained from CORBA's documentation.  The
> best way is to read CORBA specifications which are available
> from OMG website.
>
> - http://www.omg.org/spec/CORBA
> - http://www.omg.org/spec/CORBA/3.3/Interfaces/PDF
>
> But these are huge specifications, so I prefer to read VisiBroker
> programmers reference.
>
> - http://techpubs.borland.com/am/bes/v5x/v51/en/vbprogrammersref.pdf
> - http://techpubs.borland.com/am/bes/v5x/
>
> Consequently, example code would be the following.
>
>  RTC::ReturnCode_t MyServiceConsumer::onExecute(RTC::UniqueId ec_id)
>  {
>    try
>      {
>        if (CORBA::is_nil(m_myservice0._ptr()))
>          {
>            std::cout << "[nil] object reference is not assigned." <<
> std::endl;
>          }
>        else
>          {
>            if (m_myservice0->_non_existent())
>              {
>                std::cout << "[inactive] provider is inactive." <<
> std::endl;
>              }
>            else
>              {
>                std::cout << "[active] provider is active." << std::endl;
>              }
>          }
>      }
>    catch (...)
>      {
>        std::cout << "Unknown exception." << std::endl;
>      }
>    coil::sleep(1);
>    return RTC::RTC_OK;
>  }
>
> Please try the example code. At first, activate the Consumer
> component.  Before connecting service ports, the consumer state
> would be "nil."  After connecting ports, the consumer state would
> be "inactive", and after activating the Provider RTC the state
> would be "active."
>
> But if the provider RTC has one or more ExecutionContext, this
> might be broken.That's an unresolved the design problem of the
> OMG RTC specification and OpenRTM-aist implementation.
>
>
> Best regards,
> Noriaki Ando
>
>
> --
> Noriaki Ando, Ph.D.
>     Senior Research Scientist, RT-Synthesis R.G., ISRI, AIST
>     AIST Tsukuba Central 2, Tsukuba, Ibaraki 305-8568 JAPAN
>     e-mail: n-ando ＠ aist.go.jp, web: http://staff.aist.go.jp/n-ando
>     OpenRTM-aist: http://www.openrtm.org
>
>
> 2013/6/19 György Persa <persa ＠ sztaki.hu>:
> > Hello everyone,
> >
> > In my project the order of components' activation is crucial. Meanwhile,
> we
> > have an on-line tool for connecting components, which uses random order
> when
> > activating components.
> > Because of that, I'm looking for a function, which is able to decide
> whether
> > the component(s) on the other end of a service port's interface is
> activated
> > or not. Does such a function exists? If so, how to call it via an
> > RTC::CorbaComsumer<> object, for instance?
> > I've investigated the "SimpleService" example as well but couldn't find
> > anything like this in the code. MyServiceConsumer doesn't check whether
> > MyServiceProvider is active or not. It just uses try-catch blocks to
> > identify inactive service provider.
> >
> > Thanks in advance,
> > György Persa
> >
> >
> > --
> > Software engineer
> > Computer and Automation Research Institute
> > Hungarian Academy of Sciences
> > Project VirCA, www.virca.hu
> >
> > _______________________________________________
> > openrtm-users mailing list
> > openrtm-users ＠ openrtm.org
> > http://www.openrtm.org/mailman/listinfo/openrtm-users
> >
>
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