Package org.epics.archiverappliance.common

Interface DataAtTime

All Known Implementing Classes:

PlainStoragePlugin

public interface DataAtTime

Method Summary

Modifier and Type	Method	Description
Event	dataAtTime(BasicContext context, String pvName, Instant atTime, Instant startAtTime, Period searchPeriod, BiDirectionalIterable.IterationDirection iterationDirection)	Generic method to iterate over the data for specified PV.

Method Details

dataAtTime

Event dataAtTime(BasicContext context,
 String pvName,
 Instant atTime,
 Instant startAtTime,
 Period searchPeriod,
 BiDirectionalIterable.IterationDirection iterationDirection)
          throws IOException

Generic method to iterate over the data for specified PV. We provide a time to start the iteration at ( inclusive ) and a direction and a Predicate. The plugin then iterates ( forwards or backwards ) and calls the Predicate for each sample. The iteration stops when the Predicate returns false or when we run out of samples. Iteration also stops when we get an exception. So this mode of traversal is vulnerable to corruption in the data. We may relax this constraint later by providing a optional bool to ignore exceptions.

Parameters:

context -  

pvName - The PV name

atTime - Time looking for.

startAtTime - Time to start looking from.

searchPeriod - - An estimate on the amount of time we want to iterate. This is used to determine the appropriate chunks containing data at a very high level and thus to limit the search. The predicate itself is the one that controls when the iteration terminates. So, for example, you could specify a searchPeriod of 1 year but stop the iteration after 1 minute

Throws:

IOException -