Package org.epics.archiverappliance

Interface Reader

All Known Subinterfaces:

StoragePlugin

All Known Implementing Classes:

BlackholeStoragePlugin, ChannelArchiverReadOnlyPlugin, MergeDedupStoragePlugin, PBOverHTTPStoragePlugin, PlainStoragePlugin

public interface Reader

The main data retrieval interface; this is used to get an EventStream for events for one PV between a start and an end time. If a sample does not exist between these intervals, we'll need to return the last known value The reader interface is almost always used as part of the storage plugin interfaces.

Author:

mshankar

Method Summary

Modifier and Type	Method	Description
List<Callable<EventStream>>	getDataForPV(BasicContext context, String pvName, Instant startTime, Instant endTime, PostProcessor postProcessor)
Event	getFirstKnownEvent(BasicContext context, String pvName)	Get the first event for this PV.

Method Details

getDataForPV

List<Callable<EventStream>> getDataForPV(BasicContext context,
 String pvName,
 Instant startTime,
 Instant endTime,
 PostProcessor postProcessor)
                                  throws IOException

Throws:

IOException

getFirstKnownEvent

Event getFirstKnownEvent(BasicContext context,
 String pvName)
                  throws IOException

Get the first event for this PV. This call is used to optimize away calls to other readers that have older data.

Parameters:

context -  

pvName - The PV name

Returns:

Event The first event of pvName

Throws:

IOException -