Package org.epics.archiverappliance.common

Interface BiDirectionalIterable

All Known Implementing Classes:

MergeDedupStoragePlugin

public interface BiDirectionalIterable

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static enum	BiDirectionalIterable.IterationDirection

Method Summary

Modifier and Type	Method	Description
void	iterate(BasicContext context, String pvName, Instant startAtTime, Predicate<Event> thePredicate, BiDirectionalIterable.IterationDirection direction, Period searchPeriod)	Generic method to iterate over the data for specified PV.

Method Details

iterate

void iterate(BasicContext context,
 String pvName,
 Instant startAtTime,
 Predicate<Event> thePredicate,
 BiDirectionalIterable.IterationDirection direction,
 Period searchPeriod)
      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

startAtTime - Start the iteration at this time. If going forwards, this is the first sample on or before the specified time. If going backwards, this is the first sample on or after the specified time.

thePredicate - - the Predicate to apply

direction - - Forwards or backwards

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 -