org.apache.cassandra.io.util

Class SegmentedFile

java.lang.Object

org.apache.cassandra.utils.concurrent.SharedCloseableImpl

org.apache.cassandra.io.util.SegmentedFile

All Implemented Interfaces:

java.lang.AutoCloseable, SharedCloseable

Direct Known Subclasses:

BufferedSegmentedFile, CompressedSegmentedFile, MmappedSegmentedFile

public abstract class SegmentedFile
extends SharedCloseableImpl

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

Nested Classes

Modifier and Type	Class and Description
static class	SegmentedFile.Builder Collects potential segmentation points in an underlying file, and builds a SegmentedFile to represent it.
protected static class	SegmentedFile.Cleanup

Field Summary

Fields

Modifier and Type	Field and Description
int	bufferSize
ChannelProxy	channel
long	length
long	onDiskLength

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	SegmentedFile(SegmentedFile.Cleanup cleanup, ChannelProxy channel, int bufferSize, long length, long onDiskLength)
protected	SegmentedFile(SegmentedFile copy)

Method Summary

Modifier and Type	Method and Description
RandomAccessReader	createReader()
FileDataInput	createReader(long position)
RandomAccessReader	createReader(com.google.common.util.concurrent.RateLimiter limiter)
void	dropPageCache(long before)
static SegmentedFile.Builder	getBuilder(Config.DiskAccessMode mode, boolean compressed)
static SegmentedFile.Builder	getCompressedBuilder(CompressedSequentialWriter writer)
java.lang.String	path()
abstract SegmentedFile	sharedCopy()
java.lang.String	toString()

Methods inherited from class org.apache.cassandra.utils.concurrent.SharedCloseableImpl

addTo, close, close, isCleanedUp

Methods inherited from class java.lang.Object

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

Field Detail

channel

public final ChannelProxy channel

bufferSize

public final int bufferSize

length

public final long length

onDiskLength

public final long onDiskLength

Constructor Detail

SegmentedFile

protected SegmentedFile(SegmentedFile.Cleanup cleanup,
                        ChannelProxy channel,
                        int bufferSize,
                        long length,
                        long onDiskLength)

SegmentedFile

protected SegmentedFile(SegmentedFile copy)

Method Detail

path

public java.lang.String path()

sharedCopy

public abstract SegmentedFile sharedCopy()

Returns:

a new instance of the object representing the same state and backed by the same underlying resources. Coordinates with the original (and other instances) when the underlying resource should be closed. Throws an exception if the shared resource has already been closed.

createReader

public RandomAccessReader createReader()

createReader

public RandomAccessReader createReader(com.google.common.util.concurrent.RateLimiter limiter)

createReader

public FileDataInput createReader(long position)

dropPageCache

public void dropPageCache(long before)

getBuilder

public static SegmentedFile.Builder getBuilder(Config.DiskAccessMode mode,
                                               boolean compressed)

Returns:

A SegmentedFile.Builder.

getCompressedBuilder

public static SegmentedFile.Builder getCompressedBuilder(CompressedSequentialWriter writer)

toString

public java.lang.String toString()

Overrides:

toString in class java.lang.Object