org.apache.flink.streaming.api.functions.source

Class SocketTextStreamFunction

java.lang.Object

org.apache.flink.streaming.api.functions.source.SocketTextStreamFunction

All Implemented Interfaces:

Serializable, Function, SourceFunction<String>

public class SocketTextStreamFunction
extends Object
implements SourceFunction<String>

A source function that reads strings from a socket. The source will read bytes from the socket stream and convert them to characters, each byte individually. When the delimiter character is received, the function will output the current string, and begin a new string.

The function strips trailing carriage return characters (\r) when the delimiter is the newline character (\n).

The function can be set to reconnect to the server socket in case that the stream is closed on the server side.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.flink.streaming.api.functions.source.SourceFunction

SourceFunction.SourceContext<T>

Constructor Summary

Constructors

Constructor and Description
SocketTextStreamFunction(String hostname, int port, char delimiter, long maxNumRetries)
SocketTextStreamFunction(String hostname, int port, char delimiter, long maxNumRetries, long delayBetweenRetries)

Method Summary

Methods

Modifier and Type	Method and Description
void	cancel() Cancels the source.
void	run(SourceFunction.SourceContext<String> ctx) Starts the source.

Methods inherited from class java.lang.Object

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

Constructor Detail

SocketTextStreamFunction

public SocketTextStreamFunction(String hostname,
                        int port,
                        char delimiter,
                        long maxNumRetries)

SocketTextStreamFunction

public SocketTextStreamFunction(String hostname,
                        int port,
                        char delimiter,
                        long maxNumRetries,
                        long delayBetweenRetries)

Method Detail

run

public void run(SourceFunction.SourceContext<String> ctx)
         throws Exception

Description copied from interface: SourceFunction

Starts the source. You can use the Collector parameter to emit elements. Sources that implement Checkpointed must lock on the checkpoint lock (using a synchronized block) before updating internal state and/or emitting elements. Also, the update of state and emission of elements must happen in the same synchronized block.

Specified by:

run in interface SourceFunction<String>

Parameters:

ctx - The context for interaction with the outside world.

Throws:

Exception

cancel

public void cancel()

Description copied from interface: SourceFunction

Cancels the source. Most sources will have a while loop inside the SourceFunction.run(org.apache.flink.streaming.api.functions.source.SourceFunction.SourceContext<T>) method. You need to ensure that the source will break out of this loop. This can be achieved by having a volatile field "isRunning" that is checked in the loop and that is set to false in this method.

Specified by:

cancel in interface SourceFunction<String>