org.apache.hadoop.hbase.io.hfile
Class HFile.Reader

java.lang.Object
  org.apache.hadoop.hbase.io.hfile.HFile.Reader

All Implemented Interfaces:

java.io.Closeable

Enclosing class:

HFile

public static class HFile.Reader
extends java.lang.Object
implements java.io.Closeable

HFile Reader.

Nested Class Summary

protected static class

HFile.Reader.Scanner

Field Summary

int	blockLoads
int	cacheHits
int	metaLoads
protected java.lang.String	name

Constructor Summary

HFile.Reader(org.apache.hadoop.fs.FileSystem fs, org.apache.hadoop.fs.Path path, BlockCache cache, boolean inMemory)
Opens a HFile.

HFile.Reader(org.apache.hadoop.fs.FSDataInputStream fsdis, long size, BlockCache cache, boolean inMemory)
Opens a HFile.

Method Summary

protected int	blockContainingKey(byte[] key, int offset, int length)
void	close()
org.apache.hadoop.io.RawComparator<byte[]>	getComparator()
int	getEntries()
int	getFilterEntries()
byte[]	getFirstKey()
byte[]	getFirstRowKey()
byte[]	getLastKey()
byte[]	getLastRowKey()
java.nio.ByteBuffer	getMetaBlock(java.lang.String metaBlockName, boolean cacheBlock)
java.lang.String	getName()
HFileScanner	getScanner(boolean cacheBlocks, boolean pread) Create a Scanner on this file.
java.lang.String	getTrailerInfo()
long	indexSize()
boolean	inMemory()
long	length()
java.util.Map<byte[],byte[]>	loadFileInfo() Read in the index and file info.
byte[]	midkey()
java.lang.String	toString()
protected java.lang.String	toStringFirstKey()
protected java.lang.String	toStringLastKey()

Methods inherited from class java.lang.Object

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

Field Detail

cacheHits

public int cacheHits

blockLoads

public int blockLoads

metaLoads

public int metaLoads

name

protected java.lang.String name

Constructor Detail

HFile.Reader

public HFile.Reader(org.apache.hadoop.fs.FileSystem fs,
                    org.apache.hadoop.fs.Path path,
                    BlockCache cache,
                    boolean inMemory)
             throws java.io.IOException

Opens a HFile. You must load the file info before you can use it by calling loadFileInfo().

Parameters:

fs - filesystem to load from

path - path within said filesystem

cache - block cache. Pass null if none.

Throws:

java.io.IOException

HFile.Reader

public HFile.Reader(org.apache.hadoop.fs.FSDataInputStream fsdis,
                    long size,
                    BlockCache cache,
                    boolean inMemory)

Opens a HFile. You must load the index before you can use it by calling loadFileInfo().

Parameters:

fsdis - input stream. Caller is responsible for closing the passed stream.

size - Length of the stream.

cache - block cache. Pass null if none.

Throws:

java.io.IOException

Method Detail

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object

toStringFirstKey

protected java.lang.String toStringFirstKey()

toStringLastKey

protected java.lang.String toStringLastKey()

length

public long length()

inMemory

public boolean inMemory()

loadFileInfo

public java.util.Map<byte[],byte[]> loadFileInfo()
                                          throws java.io.IOException

Read in the index and file info.

Returns:

A map of fileinfo data. See HFile.Writer.appendFileInfo(byte[], byte[]).

Throws:

java.io.IOException

getScanner

public HFileScanner getScanner(boolean cacheBlocks,
                               boolean pread)

Create a Scanner on this file. No seeks or reads are done on creation. Call HFileScanner.seekTo(byte[]) to position an start the read. There is nothing to clean up in a Scanner. Letting go of your references to the scanner is sufficient.

Parameters:

pread - Use positional read rather than seek+read if true (pread is better for random reads, seek+read is better scanning).

cacheBlocks - True if we should cache blocks read in by this scanner.

Returns:

Scanner on this file.

blockContainingKey

protected int blockContainingKey(byte[] key,
                                 int offset,
                                 int length)

Parameters:

key - Key to search.

Returns:

Block number of the block containing the key or -1 if not in this file.

getMetaBlock

public java.nio.ByteBuffer getMetaBlock(java.lang.String metaBlockName,
                                        boolean cacheBlock)
                                 throws java.io.IOException

Parameters:

metaBlockName -

cacheBlock - Add block to cache, if found

Returns:

Block wrapped in a ByteBuffer

Throws:

java.io.IOException

getFirstKey

public byte[] getFirstKey()

Returns:

First key in the file. May be null if file has no entries. Note that this is not the first rowkey, but rather the byte form of the first KeyValue.

getFirstRowKey

public byte[] getFirstRowKey()

Returns:

the first row key, or null if the file is empty. TODO move this to StoreFile after Ryan's patch goes in to eliminate KeyValue here

getEntries

public int getEntries()

Returns:

number of KV entries in this HFile

getLastKey

public byte[] getLastKey()

Returns:

Last key in the file. May be null if file has no entries. Note that this is not the last rowkey, but rather the byte form of the last KeyValue.

getLastRowKey

public byte[] getLastRowKey()

Returns:

the last row key, or null if the file is empty. TODO move this to StoreFile after Ryan's patch goes in to eliminate KeyValue here

getFilterEntries

public int getFilterEntries()

Returns:

number of K entries in this HFile's filter. Returns KV count if no filter.

getComparator

public org.apache.hadoop.io.RawComparator<byte[]> getComparator()

Returns:

Comparator.

indexSize

public long indexSize()

Returns:

index size

midkey

public byte[] midkey()
              throws java.io.IOException

Returns:

Midkey for this file. We work with block boundaries only so returned midkey is an approximation only.

Throws:

java.io.IOException

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Throws:

java.io.IOException

getName

public java.lang.String getName()

getTrailerInfo

public java.lang.String getTrailerInfo()