Package org.apache.flink.state.forst.fs.cache

Class FileCacheEntry

java.lang.Object

org.apache.flink.runtime.asyncprocessing.ReferenceCounted<Object>

org.apache.flink.state.forst.fs.cache.FileCacheEntry

public final class FileCacheEntry
extends org.apache.flink.runtime.asyncprocessing.ReferenceCounted<Object>

A file cache entry that encapsulates file and the size of the file, and provides methods to read or write file. Not thread safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	FileCacheEntry.EntryStatus	The status of a file cache entry.

Method Summary

Modifier and Type	Method	Description
CachedDataInputStream	open(org.apache.flink.core.fs.FSDataInputStream originalStream)	Opens a new CachedDataInputStream from this cache entry.
protected void	referenceCountReachedZero(Object o)	Only two scenario that the reference count can reach 0. 1.

Methods inherited from class org.apache.flink.runtime.asyncprocessing.ReferenceCounted

getReferenceCount, release, release, retain, tryRetain

Methods inherited from class java.lang.Object

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

Method Details

open

public CachedDataInputStream open(org.apache.flink.core.fs.FSDataInputStream originalStream)
                           throws IOException

Opens a new CachedDataInputStream from this cache entry. If the cache stream is available, it will be used; otherwise, the original stream will be used. But the cache stream will be used once available. The opened stream is added to the queue of opened streams associated with this cache entry.

Parameters:

originalStream - the original input stream to be used if the cache stream is not available

Returns:

a new CachedDataInputStream for reading data

Throws:

IOException - if an I/O error occurs while opening the stream

referenceCountReachedZero

protected void referenceCountReachedZero(@Nullable
 Object o)

Only two scenario that the reference count can reach 0. 1. The cache entry is invalid the reference count is released. 2. The cache entry is closed and the reference count is scheduled released.

Specified by:

referenceCountReachedZero in class org.apache.flink.runtime.asyncprocessing.ReferenceCounted<Object>