org.apache.cassandra.io.util
Class SegmentedFile

java.lang.Object
  org.apache.cassandra.io.util.SegmentedFile

Direct Known Subclasses:

BufferedSegmentedFile, MmappedSegmentedFile

public abstract class SegmentedFile
extends java.lang.Object

Abstracts a read-only file that has been split into segments, each of which can be represented by an independent FileDataInput. Allows for iteration over the FileDataInputs, or random access to the FileDataInput for a given position. The JVM can only map up to 2GB at a time, so each segment is at most that size when using mmap i/o. If a segment would need to be longer than 2GB, that segment will not be mmap'd, and a new RandomAccessFile will be created for each access to that segment.

Nested Class Summary

static class

SegmentedFile.Builder Collects potential segmentation points in an underlying file, and builds a SegmentedFile to represent it.

Field Summary

long	length
java.lang.String	path

Method Summary

static SegmentedFile.Builder	getBuilder(Config.DiskAccessMode mode)
abstract FileDataInput	getSegment(long position, int bufferSize)
java.util.Iterator<FileDataInput>	iterator(long position, int bufferSize)

Methods inherited from class java.lang.Object

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

Field Detail

path

public final java.lang.String path

length

public final long length

Method Detail

getBuilder

public static SegmentedFile.Builder getBuilder(Config.DiskAccessMode mode)

Returns:

A SegmentedFile.Builder.

getSegment

public abstract FileDataInput getSegment(long position,
                                         int bufferSize)

iterator

public java.util.Iterator<FileDataInput> iterator(long position,
                                                  int bufferSize)

Returns:

An Iterator over segments, beginning with the segment containing the given position: each segment must be closed after use.