alluxio.client.file.cache

Class LocalCachePositionReader

java.lang.Object

alluxio.client.file.cache.LocalCachePositionReader

All Implemented Interfaces:

PositionReader, Closeable, AutoCloseable

@ThreadSafe
public class LocalCachePositionReader
extends Object
implements PositionReader

Implementation of PositionReader that reads from a local cache if possible.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	mPageSize Page size in bytes.

Method Summary

Modifier and Type	Method and Description
void	close() Closes the positon reader and do cleanup job if any.
static LocalCachePositionReader	create(AlluxioConfiguration conf, CacheManager cacheManager, CloseableSupplier<PositionReader> fallbackReader, URIStatus status, long pageSize, CacheContext cacheContext)
static LocalCachePositionReader	create(CacheManager cacheManager, CloseableSupplier<PositionReader> fallbackReader, FileId fileId, long fileSize, long pageSize, CacheContext cacheContext)
protected com.google.common.base.Stopwatch	createUnstartedStopwatch()
Optional<DataFileChannel>	getDataFileChannel(long position, int length) Get a DataFileChannel which wraps a FileRegion.
long	getPageSize() Get the page size.
int	readInternal(long position, ReadTargetBuffer buffer, int length)

Methods inherited from class java.lang.Object

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

Methods inherited from interface alluxio.PositionReader

read, read, read, read, read

Field Detail

mPageSize

protected final long mPageSize

Page size in bytes.

Method Detail

create

public static LocalCachePositionReader create(AlluxioConfiguration conf,
                                              CacheManager cacheManager,
                                              CloseableSupplier<PositionReader> fallbackReader,
                                              URIStatus status,
                                              long pageSize,
                                              CacheContext cacheContext)

Parameters:

conf -

cacheManager -

fallbackReader -

status -

pageSize -

cacheContext -

Returns:

LocalCachePositionReader

create

public static LocalCachePositionReader create(CacheManager cacheManager,
                                              CloseableSupplier<PositionReader> fallbackReader,
                                              FileId fileId,
                                              long fileSize,
                                              long pageSize,
                                              CacheContext cacheContext)

Parameters:

cacheManager -

fallbackReader -

fileId -

fileSize -

pageSize -

cacheContext -

Returns:

LocalCachePositionReader

readInternal

public int readInternal(long position,
                        ReadTargetBuffer buffer,
                        int length)
                 throws IOException

Specified by:

readInternal in interface PositionReader

Parameters:

position - position of the file to start reading data

buffer - target byte buffer

length - bytes to read

Returns:

bytes read, or -1 none of data is read

Throws:

IOException

close

public void close()
           throws IOException

Description copied from interface: PositionReader

Closes the positon reader and do cleanup job if any.

Specified by:

close in interface PositionReader

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Throws:

IOException

getDataFileChannel

public Optional<DataFileChannel> getDataFileChannel(long position,
                                                    int length)

Get a DataFileChannel which wraps a FileRegion.

Parameters:

position - the start position to read

length - how many bytes to read

Returns:

an object of DataFileChannel

createUnstartedStopwatch

protected com.google.common.base.Stopwatch createUnstartedStopwatch()

getPageSize

public long getPageSize()

Get the page size.

Returns:

the page size