Tune polling from inside device classes

audience:developers lang:all

It is possible to configure command or attribute polling from within a device class, i.e. an instance of Tango::DeviceImpl. The available functionality is similiar to the one found in Tango::DeviceProxy.

With them, you can:

• Check if a command or attribute is polled

• Start/stop polling for a command or an attribute

• Get or update the polling period for a polled attribute or command

C++

To display some information related to polling of the attribute named TheAtt:

std::string att_name{"TheAtt"};
TANGO_LOG_DEBUG << "Attribute" << att_name;

if(is_attribute_polled(att_name))
{
   TANGO_LOG_DEBUG << " is polled with period " << get_attribute_poll_period(att_name) << " ms" << std::endl;
}
else
{
   TANGO_LOG_DEBUG << " is not polled" << std::endl;
}

To poll a command:

poll_command("TheCmd", 250);

If the command is already polled, this method will update its polling period to 250 ms.

Finally, to stop polling the same command:

stop_poll_command("TheCmd");

All these DeviceImpl polling related methods are documented in the DeviceImpl class documentation.

Python

To display some information related to polling of the attribute named TheAtt in a DeviceImpl class:

att_name = "TheAtt"

if self.is_attribute_polled(att_name):
    print(f"{} is polled with period {} ms", att_name, self.get_attribute_poll_period(att_name))
else:
    print(f"{} is not polled", att_name)

To poll a command:

self.poll_command("TheCmd", 250)

If the command is already polled, this method will update its polling period to 250 ms.

Finally, to stop polling:

self.stop_poll_command("TheCmd")

All these DeviceImpl polling related methods are documented in DeviceImpl.

Java

The polling can be retrieved and modified from the DeviceManager class.

import org.tango.server.annotation.Device;
import org.tango.server.annotation.DeviceManagement;
import org.tango.server.device.DeviceManager;
import fr.esrf.Tango.DevFailed;

@Device
public class Test {
    @DeviceManagement
    private DeviceManager deviceManager;
     ...
        final String attName = "TheAttr";
        if (deviceManager.isPolled(attName)) {
            System.out.println(attName + " is polled with period " + deviceManager.getPollingPeriod(attName) + " mS");
        } else {
            System.out.println(attName + " is not polled");
        }
        deviceManager.startPolling("TheCmd", 250);
        deviceManager.stopPolling("TheCmd")
        ...

   public void setDeviceManager(final DeviceManager deviceManager) {
        this.deviceManager = deviceManager;
    }
}