Package edu.stanford.slac.archiverappliance.plain.pb

Class FileBackedPBEventStream

java.lang.Object

edu.stanford.slac.archiverappliance.plain.pb.FileBackedPBEventStream

All Implemented Interfaces:

ETLPBByteStream, Closeable, AutoCloseable, Iterable<Event>, RemotableOverRaw, ETLBulkStream, EventStream

public class FileBackedPBEventStream
extends Object
implements EventStream, RemotableOverRaw, ETLPBByteStream

An EventStream that is backed by a single PB file. You can only get one iterator out of this event stream. This condition is also checked for. This is typically used with/after PlainPBFileNameUtility.getFilesWithData

Author:

mshankar

Constructor Summary

Constructors

Constructor	Description
FileBackedPBEventStream(String pvname, Path path, ArchDBRTypes type)	Used when we want to include data from the entire file.
FileBackedPBEventStream(String pvname, Path path, ArchDBRTypes type, long startPosition, long endPosition)	Used when we know the file locations of the start and end.
FileBackedPBEventStream(String pvname, Path path, ArchDBRTypes dbrtype, Instant startTime, Instant endTime, boolean skipSearch)	Used when we know the start and end times.
FileBackedPBEventStream(String pvname, Path path, ArchDBRTypes dbrtype, Instant startAtTime, BiDirectionalIterable.IterationDirection direction)	Used for unlimited iteration.

Method Summary

Modifier and Type	Method	Description
void	close()
ReadableByteChannel	getByteChannel(BasicContext context)	Get a byte channel positioned at the first event (after the header).
RemotableEventStreamDesc	getDescription()
Event	getFirstEvent(BasicContext context)	Get the first event in this event stream.
String	getPvName()
Iterator<Event>	iterator()

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Constructor Details

FileBackedPBEventStream

public FileBackedPBEventStream(String pvname,
 Path path,
 ArchDBRTypes type)
                        throws IOException

Used when we want to include data from the entire file.

Parameters:

pvname - The PV name

path - path

type - Enum ArchDBRTypes

Throws:

IOException -  

FileBackedPBEventStream

public FileBackedPBEventStream(String pvname,
 Path path,
 ArchDBRTypes type,
 long startPosition,
 long endPosition)
                        throws IOException

Used when we know the file locations of the start and end. Really only used in one utility...

Parameters:

pvname - The PV name

path - Path

type - Enum ArchDBRTypes

startPosition - The file location of the start

endPosition - The file location of the end

Throws:

IOException -  

FileBackedPBEventStream

public FileBackedPBEventStream(String pvname,
 Path path,
 ArchDBRTypes dbrtype,
 Instant startTime,
 Instant endTime,
 boolean skipSearch)
                        throws IOException

Used when we know the start and end times. There are six cases here; see the FileBackedIteratorTest for more details. For performance reasons, we want to use the location based iterator as much as possible. But in case of issues, we do not want to not return data. So, fall back to a time based iterator

Parameters:

pvname - The PV name

path - Path

dbrtype - Enum ArchDBRTypes

startTime - The start time

endTime - The end time

skipSearch - true or false

Throws:

IOException -  

FileBackedPBEventStream

public FileBackedPBEventStream(String pvname,
 Path path,
 ArchDBRTypes dbrtype,
 Instant startAtTime,
 BiDirectionalIterable.IterationDirection direction)
                        throws IOException

Used for unlimited iteration. We specify a time to start the iteration at and a direction.

Parameters:

pvname - The PV name

path - Path

dbrtype - Enum ArchDBRTypes

startAtTime - Start iteration at time

Throws:

IOException -  

Method Details

iterator

public Iterator<Event> iterator()

Specified by:

iterator in interface Iterable<Event>

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

getDescription

public RemotableEventStreamDesc getDescription()

Specified by:

getDescription in interface EventStream

Specified by:

getDescription in interface RemotableOverRaw

getPvName

public String getPvName()

getFirstEvent

public Event getFirstEvent(BasicContext context)
                    throws IOException

Description copied from interface: ETLBulkStream

Get the first event in this event stream. If there are no events in this stream, return null.

Specified by:

getFirstEvent in interface ETLBulkStream

Parameters:

context - BasicContext

Returns:

Event return the first event, or null

Throws:

IOException -  

getByteChannel

public ReadableByteChannel getByteChannel(BasicContext context)
                                   throws IOException

Description copied from interface: ETLPBByteStream

Get a byte channel positioned at the first event (after the header).

Specified by:

getByteChannel in interface ETLPBByteStream

Parameters:

context - BasicContext

Returns:

ReadableByteChannel A channel that can read bytes.

Throws:

IOException -  

See Also:

• java.nio.channels.ReadableByteChannel