org.apache.flink.runtime.io.network.api.writer

Class RoundRobinChannelSelector<T extends org.apache.flink.core.io.IOReadableWritable>

java.lang.Object

org.apache.flink.runtime.io.network.api.writer.RoundRobinChannelSelector<T>

Type Parameters:

T - the type of record which is sent through the attached output gate

All Implemented Interfaces:

ChannelSelector<T>

public class RoundRobinChannelSelector<T extends org.apache.flink.core.io.IOReadableWritable>
extends Object
implements ChannelSelector<T>

This is the default implementation of the ChannelSelector interface. It represents a simple round-robin strategy, i.e. regardless of the record every attached exactly one output channel is selected at a time.

Constructor Summary

Constructors

Constructor and Description
RoundRobinChannelSelector()

Method Summary

Modifier and Type	Method and Description
boolean	isBroadcast() Returns whether the channel selector always selects all the output channels.
int	selectChannel(T record) Returns the logical channel index, to which the given record should be written.
void	setup(int numberOfChannels) Initializes the channel selector with the number of output channels.

Methods inherited from class java.lang.Object

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

Constructor Detail

RoundRobinChannelSelector

public RoundRobinChannelSelector()

Method Detail

setup

public void setup(int numberOfChannels)

Description copied from interface: ChannelSelector

Initializes the channel selector with the number of output channels.

Specified by:

setup in interface ChannelSelector<T extends org.apache.flink.core.io.IOReadableWritable>

Parameters:

numberOfChannels - the total number of output channels which are attached to respective output gate.

selectChannel

public int selectChannel(T record)

Description copied from interface: ChannelSelector

Returns the logical channel index, to which the given record should be written. It is illegal to call this method for broadcast channel selectors and this method can remain not implemented in that case (for example by throwing UnsupportedOperationException).

Specified by:

selectChannel in interface ChannelSelector<T extends org.apache.flink.core.io.IOReadableWritable>

Parameters:

record - the record to determine the output channels for.

Returns:

an integer number which indicates the index of the output channel through which the record shall be forwarded.

isBroadcast

public boolean isBroadcast()

Description copied from interface: ChannelSelector

Returns whether the channel selector always selects all the output channels.

Specified by:

isBroadcast in interface ChannelSelector<T extends org.apache.flink.core.io.IOReadableWritable>

Returns:

true if the selector is for broadcast mode.