org.apache.hadoop.hbase.regionserver
Interface KeyValueScanner

All Known Implementing Classes:

KeyValueHeap, MemStore.MemStoreScanner

public interface KeyValueScanner

Scanner that returns the next KeyValue.

Method Summary

void	close() Close the KeyValue scanner.
long	getSequenceID() Get the sequence id associated with this KeyValueScanner.
KeyValue	next() Return the next KeyValue in this scanner, iterating the scanner
KeyValue	peek() Look at the next KeyValue in this scanner, but do not iterate scanner.
boolean	reseek(KeyValue key) Reseek the scanner at or after the specified KeyValue.
boolean	seek(KeyValue key) Seek the scanner at or after the specified KeyValue.

Method Detail

peek

KeyValue peek()

Look at the next KeyValue in this scanner, but do not iterate scanner.

Returns:

the next KeyValue

next

KeyValue next()
              throws java.io.IOException

Return the next KeyValue in this scanner, iterating the scanner

Returns:

the next KeyValue

Throws:

java.io.IOException

seek

boolean seek(KeyValue key)
             throws java.io.IOException

Seek the scanner at or after the specified KeyValue.

Parameters:

key - seek value

Returns:

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

Throws:

java.io.IOException

reseek

boolean reseek(KeyValue key)
               throws java.io.IOException

Reseek the scanner at or after the specified KeyValue. This method is guaranteed to seek to or before 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:

key - seek value (should be non-null)

Returns:

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

Throws:

java.io.IOException

getSequenceID

long getSequenceID()

Get the sequence id associated with this KeyValueScanner. This is required for comparing multiple files to find out which one has the latest data. The default implementation for this would be to return 0. A file having lower sequence id will be considered to be the older one.

close

void close()

Close the KeyValue scanner.