org.apache.hadoop.hbase.io.hfile

Class AbstractHFileReader.Scanner

java.lang.Object

org.apache.hadoop.hbase.io.hfile.AbstractHFileReader.Scanner

All Implemented Interfaces:

HFileScanner

Direct Known Subclasses:

HFileReaderV2.AbstractScannerV2

Enclosing class:

AbstractHFileReader

protected abstract static class AbstractHFileReader.Scanner
extends Object
implements HFileScanner

Field Summary

Fields

Modifier and Type	Field and Description
protected ByteBuffer	blockBuffer
protected int	blockFetches
protected boolean	cacheBlocks
protected int	currKeyLen
protected long	currMemstoreTS
protected int	currMemstoreTSLen
protected int	currValueLen
protected boolean	isCompaction
protected boolean	pread
protected HFile.Reader	reader

Constructor Summary

Constructors

Constructor and Description
Scanner(HFile.Reader reader, boolean cacheBlocks, boolean pread, boolean isCompaction)

Method Summary

Modifier and Type	Method and Description
protected void	assertSeeked()
HFile.Reader	getReader()
boolean	isSeeked()
int	reseekTo(byte[] key) Reseek to or just before the passed key.
boolean	seekBefore(byte[] key) Consider the key stream of all the keys in the file, k[0] ..
int	seekTo(byte[] key) SeekTo or just before the passed key.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.hadoop.hbase.io.hfile.HFileScanner

getKey, getKeyString, getKeyValue, getNextIndexedKey, getValue, getValueString, next, reseekTo, reseekTo, seekBefore, seekBefore, seekTo, seekTo, seekTo

Field Detail

blockBuffer

protected ByteBuffer blockBuffer

cacheBlocks

protected boolean cacheBlocks

pread

protected final boolean pread

isCompaction

protected final boolean isCompaction

currKeyLen

protected int currKeyLen

currValueLen

protected int currValueLen

currMemstoreTSLen

protected int currMemstoreTSLen

currMemstoreTS

protected long currMemstoreTS

blockFetches

protected int blockFetches

reader

protected final HFile.Reader reader

Constructor Detail

Scanner

public Scanner(HFile.Reader reader,
               boolean cacheBlocks,
               boolean pread,
               boolean isCompaction)

Method Detail

isSeeked

public boolean isSeeked()

Specified by:

isSeeked in interface HFileScanner

Returns:

True is scanner has had one of the seek calls invoked; i.e. HFileScanner.seekBefore(byte[]) or HFileScanner.seekTo() or HFileScanner.seekTo(byte[]). Otherwise returns false.

toString

public String toString()

Overrides:

toString in class Object

assertSeeked

protected void assertSeeked()

seekTo

public int seekTo(byte[] key)
           throws IOException

Description copied from interface: HFileScanner

SeekTo or just before the passed key. Examine the return code to figure whether we found the key or not. Consider the key stream of all the keys in the file, k[0] .. k[n], where there are n keys in the file.

Specified by:

seekTo in interface HFileScanner

Parameters:

key - Key to find.

Returns:

-1, if key < k[0], no position; 0, such that k[i] = key and scanner is left in position i; and 1, such that k[i] < key, and scanner is left in position i. The scanner will position itself between k[i] and k[i+1] where k[i] < key <= k[i+1]. If there is no key k[i+1] greater than or equal to the input key, then the scanner will position itself at the end of the file and next() will return false when it is called.

Throws:

IOException

seekBefore

public boolean seekBefore(byte[] key)
                   throws IOException

Description copied from interface: HFileScanner

Consider the key stream of all the keys in the file, k[0] .. k[n], where there are n keys in the file.

Specified by:

seekBefore in interface HFileScanner

Parameters:

key - Key to find

Returns:

false if key <= k[0] or true with scanner in position 'i' such that: k[i] < key. Furthermore: there may be a k[i+1], such that k[i] < key <= k[i+1] but there may also NOT be a k[i+1], and next() will return false (EOF).

Throws:

IOException

reseekTo

public int reseekTo(byte[] key)
             throws IOException

Description copied from interface: HFileScanner

Reseek to or just before the passed key. Similar to seekTo except that this can be called even if the scanner is not at the beginning of a file. This can be used to seek only to keys which come after the current position of the scanner. Consider the key stream of all the keys in the file, k[0] .. k[n], where there are n keys in the file after current position of HFileScanner. The scanner will position itself between k[i] and k[i+1] where k[i] < key <= k[i+1]. If there is no key k[i+1] greater than or equal to the input key, then the scanner will position itself at the end of the file and next() will return false when it is called.

Specified by:

reseekTo in interface HFileScanner

Parameters:

key - Key to find (should be non-null)

Returns:

-1, if key < k[0], no position; 0, such that k[i] = key and scanner is left in position i; and 1, such that k[i] < key, and scanner is left in position i.

Throws:

IOException

getReader

public HFile.Reader getReader()

Specified by:

getReader in interface HFileScanner

Returns:

Reader that underlies this Scanner instance.