org.apache.beam.sdk.util

Class ShardingWritableByteChannel

java.lang.Object

org.apache.beam.sdk.util.ShardingWritableByteChannel

All Implemented Interfaces:

java.io.Closeable, java.lang.AutoCloseable, java.nio.channels.Channel, java.nio.channels.WritableByteChannel

@Internal
public class ShardingWritableByteChannel
extends java.lang.Object
implements java.nio.channels.WritableByteChannel

Implements a WritableByteChannel that may contain multiple output shards.

This provides writeToShard(int, java.nio.ByteBuffer), which takes a shard number for writing to a particular shard.

The channel is considered open if all downstream channels are open, and closes all downstream channels when closed.

Field Summary

Fields

Modifier and Type	Field and Description
static int	ALL_SHARDS Special shard number that causes a write to all shards.

Constructor Summary

Constructors

Constructor and Description
ShardingWritableByteChannel()

Method Summary

Modifier and Type	Method and Description
void	addChannel(java.nio.channels.WritableByteChannel writer) Adds another shard output channel.
void	close()
java.nio.channels.WritableByteChannel	getChannel(int shardNum) Returns the WritableByteChannel associated with the given shard number.
int	getNumShards() Returns the number of output shards.
boolean	isOpen()
int	write(java.nio.ByteBuffer src) Writes a buffer to all shards.
int	writeToShard(int shardNum, java.nio.ByteBuffer src) Writes the buffer to the given shard.

Methods inherited from class java.lang.Object

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

Field Detail

ALL_SHARDS

public static final int ALL_SHARDS

Special shard number that causes a write to all shards.

See Also:

Constant Field Values

Constructor Detail

ShardingWritableByteChannel

public ShardingWritableByteChannel()

Method Detail

getNumShards

public int getNumShards()

Returns the number of output shards.

addChannel

public void addChannel(java.nio.channels.WritableByteChannel writer)

Adds another shard output channel.

getChannel

public java.nio.channels.WritableByteChannel getChannel(int shardNum)

Returns the WritableByteChannel associated with the given shard number.

writeToShard

public int writeToShard(int shardNum,
                        java.nio.ByteBuffer src)
                 throws java.io.IOException

Writes the buffer to the given shard.

This does not change the current output shard.

Returns:

The total number of bytes written. If the shard number is ALL_SHARDS, then the total is the sum of each individual shard write.

Throws:

java.io.IOException

write

public int write(java.nio.ByteBuffer src)
          throws java.io.IOException

Writes a buffer to all shards.

Same as calling writeToShard(ALL_SHARDS, buf).

Specified by:

write in interface java.nio.channels.WritableByteChannel

Throws:

java.io.IOException

isOpen

public boolean isOpen()

Specified by:

isOpen in interface java.nio.channels.Channel

close

public void close()
           throws java.io.IOException

Specified by:

close in interface java.io.Closeable

Specified by:

close in interface java.lang.AutoCloseable

Specified by:

close in interface java.nio.channels.Channel

Throws:

java.io.IOException