org.apache.hadoop.hbase.regionserver

Class SnapshotSegmentScanner

java.lang.Object

org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner

org.apache.hadoop.hbase.regionserver.NonReversedNonLazyKeyValueScanner

org.apache.hadoop.hbase.regionserver.SnapshotSegmentScanner

All Implemented Interfaces:

Closeable, AutoCloseable, KeyValueScanner, Shipper

@InterfaceAudience.Private
public class SnapshotSegmentScanner
extends NonReversedNonLazyKeyValueScanner

A basic SegmentScanner used against an ImmutableScanner snapshot Used flushing where we do a single pass, no reverse scanning or inserts happening. Its a dumbed-down Scanner that can go fast. Like CollectionBackedScanner (but making it know about Segments was onerous).

Field Summary

Fields

Modifier and Type	Field and Description
private Cell	current
private Iterator<Cell>	iter
private ImmutableSegment	segment

Fields inherited from interface org.apache.hadoop.hbase.regionserver.KeyValueScanner

NO_NEXT_INDEXED_KEY

Constructor Summary

Constructors

Constructor and Description
SnapshotSegmentScanner(ImmutableSegment segment)

Method Summary

Modifier and Type	Method and Description
void	close() Close the KeyValue scanner.
private static Iterator<Cell>	createIterator(Segment segment)
long	getScannerOrder() Get the order of this KeyValueScanner.
Cell	next() Return the next Cell in this scanner, iterating the scanner
Cell	peek() Look at the next Cell in this scanner, but do not iterate scanner.
boolean	reseek(Cell seekCell) Reseek the scanner at or after the specified KeyValue.
boolean	seek(Cell seekCell) Seek the scanner at or after the specified KeyValue.

Methods inherited from class org.apache.hadoop.hbase.regionserver.NonReversedNonLazyKeyValueScanner

backwardSeek, seekToLastRow, seekToPreviousRow

Methods inherited from class org.apache.hadoop.hbase.regionserver.NonLazyKeyValueScanner

doRealSeek, enforceSeek, getFilePath, getNextIndexedKey, isFileScanner, realSeekDone, requestSeek, shipped, shouldUseScanner

Methods inherited from class java.lang.Object

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

Field Detail

segment

private final ImmutableSegment segment

iter

private Iterator<Cell> iter

current

private Cell current

Constructor Detail

SnapshotSegmentScanner

public SnapshotSegmentScanner(ImmutableSegment segment)

Method Detail

createIterator

private static Iterator<Cell> createIterator(Segment segment)

peek

public Cell peek()

Description copied from interface: KeyValueScanner

Look at the next Cell in this scanner, but do not iterate scanner. NOTICE: The returned cell has not been passed into ScanQueryMatcher. So it may not be what the user need.

Returns:

the next Cell

next

public Cell next()

Description copied from interface: KeyValueScanner

Return the next Cell in this scanner, iterating the scanner

Returns:

the next Cell

seek

public boolean seek(Cell seekCell)

Description copied from interface: KeyValueScanner

Seek the scanner at or after the specified KeyValue.

Parameters:

seekCell - seek value

Returns:

true if scanner has values left, false if end of scanner

reseek

public boolean reseek(Cell seekCell)

Description copied from interface: KeyValueScanner

Reseek the scanner at or after the specified KeyValue. This method is guaranteed to seek at or after the required key only if the key comes after the current position of the scanner. Should not be used to seek to a key which may come before the current position.

Parameters:

seekCell - seek value (should be non-null)

Returns:

true if scanner has values left, false if end of scanner

getScannerOrder

public long getScannerOrder()

Description copied from interface: KeyValueScanner

Get the order of this KeyValueScanner. This is only relevant for StoreFileScanners and MemStoreScanners (other scanners simply return 0). This is required for comparing multiple files to find out which one has the latest data. StoreFileScanners are ordered from 0 (oldest) to newest in increasing order. MemStoreScanner gets LONG.max since it always contains freshest data.

See Also:

KeyValueScanner.getScannerOrder()

close

public void close()

Description copied from interface: KeyValueScanner

Close the KeyValue scanner.