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Timer Event Service Examples

Contents

• Introduction
• Directory contents
• How to run this example

Introduction

From this example, you will learn how to:

• Create a simple push consumer to receive timed events.
• Register and unregister push consumers with the Timer Event Service.
• Set timed events to be sent at absolute, relative, and periodic times.
• Cancel timed events before they are sent.
• View the status of the TimerEventHandler.

Directory Contents

• TimerEventConsumer.java is a simple implementation of a push consumer that receives timed events. The methods of this class are:
  • main creates a new instance of the class, initialises it using the init method, and connects it to an EventChannel using the connect method.
  • init performs the initialisation necessary to run the example by obtaining references to the ORB, Notification Service, Naming Service and Timer Event Service. This method also writes the transient object reference for the TimerEventConsumer object to the Naming Service.
  • connect connects the push consumer to the Notification service. This method uses the getEventChannel and getSupplier methods to obtain the ProxyPushSupplier to connect this consumer to.
  • push prints out the details of a given event. The consumer receives events using the push method.
  • getEventChannel is a utility method that returns the event channel with id 0 from the Notification Service if it is present and creates a new event channel if it is not present.
  • getSupplier creates a new ProxyPushSupplier on an event channel.
  • getNotificationServer is a utility method that returns a reference to the Notification Service.
  • getNameServer is a utility method that returns a reference to the Naming Service.
  • getTimerEventServer is a utility method that returns a reference to the Timer Event Service.
  • writeIOR writes the reference to this consumer object to the Naming Service.
  • disconnect_push_consumer is required to be present in a PushConsumer but is not implemented as it is not used in this example.
  • connect_push_consumer is required to be present in a PushConsumer but is not implemented as it is not used in this example.
  • offer_change is required to be present in a PushConsumer but is not implemented as it is not used in this example.
• EventExample.java demonstrates various methods of the Timer Event Service. The methods of this class are:
  • main creates a new instance of the class, initialises it using the init method, and runs the example using the go method.
  • init performs the initialisation necessary to run the example by obtaining references to the ORB, Time Service, Naming Service, and Timer Event Service.
  • go method obtains a push consumer using the getPushConsumer method, creates an Any object which is to be sent as an event, registers the consumer and event with the TimerEventService, and obtains a handler. The method sends events using absolute timer (the sendAbsoluteEvent method), relative timer (the sendRelativeeEvent method), and periodic timer (the sendPeriodicEvent method). The method then unregisters the handler.
  • getPushConsumer obtains a reference to the consumer that was written to the Naming Service by the TimerEventConsumer part of this example.
  • sendAbsoluteEvent sets up a timed event to be sent at an absolute time which is calculated to be five seconds into the future. The method then sleeps for seven seconds until after the event should have been sent. The status of the handler is checked before and after the time is set, and after the event has been sent.
  • sendRelativeEvent sets up a timed event to be sent in five seconds time. The method then sleeps for seven seconds until after the event should have been sent. The status of the handler is checked before and after the time is set, and after the event has been sent.
  • sendPeriodicEvent sets up a timed event to be sent every two seconds. The method then sleeps for seven seconds until the event should have been sent three times. The data associated with the event is then changed. The method then sleeps for eight seconds until the event, with the changed data, should have been sent four times. The timed event is then canceled and the method sleeps for four seconds during which no further events should be sent. The status of the handler is checked at several points in this process.
  • printDetails is a utility method that prints details of a TimerEventHandler.
  • getNameServer is a utility method to obtain a reference to the Naming Service.
  • getTimeServer is a utility method to obtain a reference to the Time Service.
  • getTimerEventServer is a utility method to obtain a reference to the Timer Event Service.

How To Run This Example

To run the example, first make sure that the OpenFusion Time, Notification and Naming Services are running on your network.

If using an ORB which requires persistent POAs to be registered before they can be activated, ensure that the OpenFusion.TimerEventConsumer POA is registered.

1. Run the TimerEventConsumer:

   run com.prismt.cos.CosTime.examples.Event.TimerEventConsumer -ior iorfile 

2. In a new window, run the EventExample:

   run com.prismt.cos.CosTime.examples.Event.EventExample -ior iorfile 

After the EventExample has completed, the TimerEventConsumer can be terminated.

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