org.aksw.jena_sparql_api.io.binseach

Class BinarySearchOnSortedFile

java.lang.Object

org.aksw.jena_sparql_api.io.binseach.BinarySearchOnSortedFile

All Implemented Interfaces:

AutoCloseable, BinarySearcher

public class BinarySearchOnSortedFile
extends Object
implements BinarySearcher

Binary search over sorted files with memory mapped IO TODO Move to a separate project as this is of general use TODO Allow cache to be shared between concurrent readers

Author:

raven

Field Summary

Fields

Modifier and Type	Field and Description
protected Seekable	baseSeekable
protected long	channelSize
protected AutoCloseable	closeAction
protected byte	delimiter

Constructor Summary

Constructors

Constructor and Description
BinarySearchOnSortedFile(AutoCloseable closeAction, Seekable baseSeekable, long baseSeekableSize, byte delimiter)

Method Summary

Modifier and Type	Method and Description
void	close()
static BinarySearchOnSortedFile	create(Path path)
static long	getPosOfFirstMatch(Seekable seekable, byte delimiter, byte[] prefix) The initial position is assumed point to the delimiter The result will point to the initial position or a preceding delimiter If there is no preceding delimiter, the seekable will be positioned before start
static InputStream	newInputStream(Seekable channel, BinSearchScanState state)
InputStream	search(byte[] prefixBytes)
InputStream	search(String prefix) The high-level search method.
InputStream	searchCore(String prefix)

Methods inherited from class java.lang.Object

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

Field Detail

baseSeekable

protected Seekable baseSeekable

closeAction

protected AutoCloseable closeAction

channelSize

protected long channelSize

delimiter

protected byte delimiter

Constructor Detail

BinarySearchOnSortedFile

public BinarySearchOnSortedFile(AutoCloseable closeAction,
                                Seekable baseSeekable,
                                long baseSeekableSize,
                                byte delimiter)

Method Detail

create

public static BinarySearchOnSortedFile create(Path path)
                                       throws IOException

Throws:

IOException

newInputStream

public static InputStream newInputStream(Seekable channel,
                                         BinSearchScanState state)

search

public InputStream search(String prefix)

The high-level search method. The search result is an input stream over the matching region. The binary search will only seek the offset of the region; the end detection occurs on-the-fly when serving requested data.

Specified by:

search in interface BinarySearcher

Parameters:

prefix -

Returns:

searchCore

public InputStream searchCore(String prefix)
                       throws IOException

Throws:

IOException

search

public InputStream search(byte[] prefixBytes)
                   throws IOException

Specified by:

search in interface BinarySearcher

Throws:

IOException

getPosOfFirstMatch

public static long getPosOfFirstMatch(Seekable seekable,
                                      byte delimiter,
                                      byte[] prefix)
                               throws IOException

The initial position is assumed point to the delimiter The result will point to the initial position or a preceding delimiter If there is no preceding delimiter, the seekable will be positioned before start

Parameters:

seekable -

delimiter -

prefix -

Returns:

Throws:

IOException

close

public void close()
           throws Exception

Specified by:

close in interface AutoCloseable

Specified by:

close in interface BinarySearcher

Throws:

Exception