Package org.apache.cassandra.io.util

Class MmappedRegionsCache

java.lang.Object

org.apache.cassandra.io.util.MmappedRegionsCache

All Implemented Interfaces:

AutoCloseable

@NotThreadSafe
public class MmappedRegionsCache
extends Object
implements AutoCloseable

It is a utility class for caching MmappedRegions primarily used by a FileHandle.Builder when a handle to the same file is created multiple times (as when an sstable is opened early).

Constructor Summary

Constructors

Constructor	Description
MmappedRegionsCache()

Method Summary

Modifier and Type	Method	Description
void	close()
MmappedRegions	getOrCreate(ChannelProxy channel, long length, int bufferSize)	Looks for mmapped regions in cache.
MmappedRegions	getOrCreate(ChannelProxy channel, CompressionMetadata metadata, int bufferSize)	Looks for mmapped regions in cache.

Methods inherited from class java.lang.Object

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

Constructor Details

MmappedRegionsCache

public MmappedRegionsCache()

Method Details

getOrCreate

public MmappedRegions getOrCreate(ChannelProxy channel,
 long length,
 int bufferSize)

Looks for mmapped regions in cache. If found, a shared copy is created and extended to the provided length. If mmapped regions do not exist yet for the provided key, they are created and a shared copy is returned.

Parameters:

channel - channel for which the mmapped regions are requested

length - length of the file

Returns:

a shared copy of the cached mmapped regions

getOrCreate

public MmappedRegions getOrCreate(ChannelProxy channel,
 CompressionMetadata metadata,
 int bufferSize)

Looks for mmapped regions in cache. If found, a shared copy is created and extended according to the provided metadata. If mmapped regions do not exist yet for the provided key, they are created and a shared copy is returned.

Parameters:

channel - channel for which the mmapped regions are requested

metadata - compression metadata of the file

Returns:

a shared copy of the cached mmapped regions

close

public void close()

Specified by:

close in interface AutoCloseable