Package ch.psi.wica.controlsystem.epics.channel

Class EpicsChannelConnectionChangeSubscriber

java.lang.Object

ch.psi.wica.controlsystem.epics.channel.EpicsChannelConnectionChangeSubscriber

@Immutable
@Component
public class EpicsChannelConnectionChangeSubscriber
extends Object

Provides the functionality to monitor the specified EPICS channel and to publish updating channel value information to listening consumers.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	EpicsChannelConnectionChangeSubscriber.EpicsChannelConnectionStateChangeNotifier	Handles notification of EPICS channel connection state changes.
(package private) static class	EpicsChannelConnectionChangeSubscriber.TaskExecutorConfigurer	Provides a dedicated task executor for the EPICS channel connection change notifier.

Constructor Summary

Constructors

Constructor	Description
EpicsChannelConnectionChangeSubscriber(EpicsChannelConnectionChangeSubscriber.EpicsChannelConnectionStateChangeNotifier myExecutor)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
void	subscribe(org.epics.ca.Channel<Object> channel, Consumer<Boolean> connectionChangeHandler)	Registers a handler which will publish connection changed events.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

EpicsChannelConnectionChangeSubscriber

public EpicsChannelConnectionChangeSubscriber(@Autowired
 EpicsChannelConnectionChangeSubscriber.EpicsChannelConnectionStateChangeNotifier myExecutor)

Constructs a new instance.

Parameters:

myExecutor - the executor.

Method Details

subscribe

public void subscribe(org.epics.ca.Channel<Object> channel,
 Consumer<Boolean> connectionChangeHandler)

Registers a handler which will publish connection changed events.

This method operates synchronously but does NOT involve a network round trip.

The supplied will be called back from MULTIPLE threads derived from an internal thread pool.

Precondition: the supplied channel should never previously have been connected. Postcondition: the state of the channel will remain unaffected.

Parameters:

channel - the EPICS channel.

connectionChangeHandler - the event consumer.

Throws:

NullPointerException - if the channel argument was null.

NullPointerException - if the connectionChangeHandler argument was null.

IllegalStateException - if the channel was in an unexpected state on entry or exit.