alluxio.worker.block

Class UfsInputStreamManager

java.lang.Object

alluxio.worker.block.UfsInputStreamManager

@ThreadSafe
public class UfsInputStreamManager
extends Object

An under filesystem input stream manager that can cache seekable input streams for future reuse. The manager caches the input streams, with a time-based eviction policy of expiration configured in PropertyKey.WORKER_UFS_INSTREAM_CACHE_EXPIRE_MS. An under storage file maybe opened with multiple input streams at the same time. The manager uses UfsInputStreamIdSet to track the in-use input stream and the available ones. The manager closes the input streams after they are expired and not in-use anymore. Lock UfsInputStreamIdSet before access, and in addition to that, lock mFileIdToInputStreamIds before the resource retrieval.

Constructor Summary

Constructors

Constructor and Description
UfsInputStreamManager() Creates a new UfsInputStreamManager.

Method Summary

Modifier and Type	Method and Description
InputStream	acquire(UnderFileSystem ufs, String path, long fileId, OpenOptions openOptions) Acquires an input stream.
InputStream	acquire(UnderFileSystem ufs, String path, long fileId, OpenOptions openOptions, boolean reuse) Acquires an input stream.
void	invalidate(alluxio.worker.block.CachedSeekableInputStream inputStream) Invalidates an input stream from the cache.
void	release(InputStream inputStream) Releases an input stream.

Methods inherited from class java.lang.Object

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

Constructor Detail

UfsInputStreamManager

public UfsInputStreamManager()

Creates a new UfsInputStreamManager.

Method Detail

release

public void release(InputStream inputStream)
             throws IOException

Releases an input stream. The input stream is closed if it's already expired.

Parameters:

inputStream - the input stream to release

Throws:

IOException - when input stream fails to close

invalidate

public void invalidate(alluxio.worker.block.CachedSeekableInputStream inputStream)
                throws IOException

Invalidates an input stream from the cache.

Parameters:

inputStream - the cached input stream

Throws:

IOException - when the invalidated input stream fails to release

acquire

public InputStream acquire(UnderFileSystem ufs,
                           String path,
                           long fileId,
                           OpenOptions openOptions)
                    throws IOException

Acquires an input stream. For seekable input streams, if there is an available input stream in the cache, reuse it and repositions the offset, otherwise the manager opens a new input stream.

Parameters:

ufs - the under file system

path - the path to the under storage file

fileId - the file id

openOptions - the open options

Returns:

the acquired input stream

Throws:

IOException - if the input stream fails to open

acquire

public InputStream acquire(UnderFileSystem ufs,
                           String path,
                           long fileId,
                           OpenOptions openOptions,
                           boolean reuse)
                    throws IOException

Acquires an input stream. For seekable input streams, if there is an available input stream in the cache and reuse mode is specified, reuse it and repositions the offset, otherwise the manager opens a new input stream.

Parameters:

ufs - the under file system

path - the path to the under storage file

fileId - the file id

openOptions - the open options

reuse - true to reuse existing input stream, otherwise acquire a new stream

Returns:

the acquired input stream

Throws:

IOException - if the input stream fails to open