Package ch.psi.wica.services.stream

Class WicaStreamMetadataRequesterService

java.lang.Object

ch.psi.wica.services.stream.WicaStreamMetadataRequesterService

@Configuration
@EnableScheduling
@Service
@ThreadSafe
public class WicaStreamMetadataRequesterService
extends Object

Provides a service for starting and stopping the acquisition of metadata for the channels in a WicaStream.

Constructor Summary

Constructors

Constructor	Description
WicaStreamMetadataRequesterService(int wicaChannelResourceReleaseIntervalInSecs, boolean wicaChannelPublishChannelMetadataInitialState, org.springframework.context.ApplicationEventPublisher applicationEventPublisher)	Constructs a new instance.

Method Summary

Modifier and Type	Method	Description
void	discardChannelsThatHaveReachedEndOfLife()	This method runs periodically to scan the discard list for entries corresponding to channels whose metadata is no longer of interest.
(package private) void	startDataAcquisition(WicaStream wicaStream)	Starts metadata data acquisition for the channels in the specified stream.
(package private) void	stopDataAcquisition(WicaStream wicaStream)	Stops for the channels in the specified stream.

Methods inherited from class java.lang.Object

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

Constructor Details

WicaStreamMetadataRequesterService

WicaStreamMetadataRequesterService(@Value("${wica.channel-resource-release-interval-in-secs}")
 int wicaChannelResourceReleaseIntervalInSecs,
 @Value("${wica.channel-publish-channel-metadata-initial-state}")
 boolean wicaChannelPublishChannelMetadataInitialState,
 @Autowired
 org.springframework.context.ApplicationEventPublisher applicationEventPublisher)

Constructs a new instance.

Parameters:

wicaChannelResourceReleaseIntervalInSecs - period after which the resources associated with a Wica Channel will be released if they are no longer in use.

wicaChannelPublishChannelMetadataInitialState - determines whether a channel's initial value will be published as UNKNOWN when a channel is first created or whether nothing will be published until the first metadata information is acquired.

applicationEventPublisher - reference to the application publisher which will be used to publish the channels to acquire metadata for or which are no longer of interest.

Method Details

discardChannelsThatHaveReachedEndOfLife

@Scheduled(fixedRate=1000L)
public void discardChannelsThatHaveReachedEndOfLife()

This method runs periodically to scan the discard list for entries corresponding to channels whose metadata is no longer of interest.

startDataAcquisition

void startDataAcquisition(WicaStream wicaStream)

Starts metadata data acquisition for the channels in the specified stream.

Parameters:

wicaStream - the stream to acquire metadata for.

stopDataAcquisition

void stopDataAcquisition(WicaStream wicaStream)

Stops for the channels in the specified stream.

Parameters:

wicaStream - the stream that is no longer of interest.