Package org.apache.flink.runtime.state.filesystem

Class FileBasedStateOutputStream

java.lang.Object

java.io.OutputStream

org.apache.flink.core.fs.FSDataOutputStream

org.apache.flink.runtime.state.CheckpointStateOutputStream

org.apache.flink.runtime.state.filesystem.FileBasedStateOutputStream

All Implemented Interfaces:

Closeable, Flushable, AutoCloseable

public final class FileBasedStateOutputStream
extends CheckpointStateOutputStream

A CheckpointStateOutputStream that writes into a specified file and returns a FileStateHandle upon closing.

Unlike the FsCheckpointStreamFactory.FsCheckpointStateOutputStream, this stream does not have a threshold below which it returns a memory byte stream handle, and does not create random files, but writes to a specified file.

Constructor Summary

Constructors

Constructor	Description
FileBasedStateOutputStream(org.apache.flink.core.fs.FileSystem fileSystem, org.apache.flink.core.fs.Path path)

Method Summary

Modifier and Type	Method	Description
void	close()	This method should close the stream, if has not been closed before.
FileStateHandle	closeAndGetHandle()	Closes the stream and gets a state handle that can create an input stream producing the data written to this stream.
void	flush()
long	getPos()
boolean	isClosed()
void	sync()
void	write(byte[] b, int off, int len)
void	write(int b)

Methods inherited from class java.io.OutputStream

nullOutputStream, write

Methods inherited from class java.lang.Object

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

Constructor Detail

FileBasedStateOutputStream

public FileBasedStateOutputStream(org.apache.flink.core.fs.FileSystem fileSystem,
                                  org.apache.flink.core.fs.Path path)
                           throws IOException

Throws:

IOException

Method Detail

write

public final void write(int b)
                 throws IOException

Specified by:

write in class OutputStream

Throws:

IOException

write

public final void write(@Nonnull
                        byte[] b,
                        int off,
                        int len)
                 throws IOException

Overrides:

write in class OutputStream

Throws:

IOException

getPos

public long getPos()
            throws IOException

Specified by:

getPos in class org.apache.flink.core.fs.FSDataOutputStream

Throws:

IOException

flush

public void flush()
           throws IOException

Specified by:

flush in interface Flushable

Specified by:

flush in class org.apache.flink.core.fs.FSDataOutputStream

Throws:

IOException

sync

public void sync()
          throws IOException

Specified by:

sync in class org.apache.flink.core.fs.FSDataOutputStream

Throws:

IOException

isClosed

public boolean isClosed()

close

public void close()

Description copied from class: CheckpointStateOutputStream

This method should close the stream, if has not been closed before. If this method actually closes the stream, it should delete/release the resource behind the stream, such as the file that the stream writes to.

The above implies that this method is intended to be the "unsuccessful close", such as when cancelling the stream writing, or when an exception occurs. Closing the stream for the successful case must go through CheckpointStateOutputStream.closeAndGetHandle().

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in class CheckpointStateOutputStream

closeAndGetHandle

@Nullable
public FileStateHandle closeAndGetHandle()
                                  throws IOException

Description copied from class: CheckpointStateOutputStream

Closes the stream and gets a state handle that can create an input stream producing the data written to this stream.

This closing must be called (also when the caller is not interested in the handle) to successfully close the stream and retain the produced resource. In contrast, the CheckpointStateOutputStream.close() method removes the target resource when called.

Specified by:

closeAndGetHandle in class CheckpointStateOutputStream

Returns:

A state handle that can create an input stream producing the data written to this stream.

Throws:

IOException - Thrown, if the stream cannot be closed.