Package org.apache.flink.streaming.api.functions.co

Class BroadcastProcessFunction<IN1,IN2,OUT>

java.lang.Object

org.apache.flink.api.common.functions.AbstractRichFunction

org.apache.flink.streaming.api.functions.co.BaseBroadcastProcessFunction

org.apache.flink.streaming.api.functions.co.BroadcastProcessFunction<IN1,IN2,OUT>

Type Parameters:

IN1 - The input type of the non-broadcast side.

IN2 - The input type of the broadcast side.

OUT - The output type of the operator.

All Implemented Interfaces:

Serializable, org.apache.flink.api.common.functions.Function, org.apache.flink.api.common.functions.RichFunction

@PublicEvolving
public abstract class BroadcastProcessFunction<IN1,IN2,OUT>
extends BaseBroadcastProcessFunction

A function to be applied to a BroadcastConnectedStream that connects BroadcastStream, i.e. a stream with broadcast state, with a non-keyed DataStream.

The stream with the broadcast state can be created using the DataStream.broadcast(MapStateDescriptor[]) stream.broadcast(MapStateDescriptor)} method.

The user has to implement two methods:

1. the #processBroadcastElement(Object, Context, Collector) which will be applied to each element in the broadcast side
2. and the #processElement(Object, ReadOnlyContext, Collector) which will be applied to the non-broadcasted/keyed side.

The processElementOnBroadcastSide() takes as argument (among others) a context that allows it to read/write to the broadcast state, while the processElement() has read-only access to the broadcast state.

See Also:

• Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
class	BroadcastProcessFunction.Context	A context available to the broadcast side of a BroadcastConnectedStream.
class	BroadcastProcessFunction.ReadOnlyContext	A context available to the non-keyed side of a BroadcastConnectedStream (if any).

Constructor Summary

Constructors

Constructor	Description
BroadcastProcessFunction()

Method Summary

Modifier and Type	Method	Description
abstract void	processBroadcastElement(IN2 value, BroadcastProcessFunction<IN1,IN2,OUT>.Context ctx, org.apache.flink.util.Collector<OUT> out)	This method is called for each element in the broadcast stream.
abstract void	processElement(IN1 value, BroadcastProcessFunction<IN1,IN2,OUT>.ReadOnlyContext ctx, org.apache.flink.util.Collector<OUT> out)	This method is called for each element in the (non-broadcast) data stream.

Methods inherited from class org.apache.flink.api.common.functions.AbstractRichFunction

close, getIterationRuntimeContext, getRuntimeContext, open, setRuntimeContext

Methods inherited from class java.lang.Object

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

Constructor Details

BroadcastProcessFunction

public BroadcastProcessFunction()

Method Details

processElement

public abstract void processElement(IN1 value,
 BroadcastProcessFunction<IN1,IN2,OUT>.ReadOnlyContext ctx,
 org.apache.flink.util.Collector<OUT> out)
                             throws Exception

This method is called for each element in the (non-broadcast) data stream.

This function can output zero or more elements using the Collector parameter, query the current processing/event time, and also query and update the local keyed state. Finally, it has read-only access to the broadcast state. The context is only valid during the invocation of this method, do not store it.

Parameters:

value - The stream element.

ctx - A BroadcastProcessFunction<IN1,IN2,OUT>.ReadOnlyContext that allows querying the timestamp of the element, querying the current processing/event time and updating the broadcast state. The context is only valid during the invocation of this method, do not store it.

out - The collector to emit resulting elements to

Throws:

Exception - The function may throw exceptions which cause the streaming program to fail and go into recovery.

processBroadcastElement

public abstract void processBroadcastElement(IN2 value,
 BroadcastProcessFunction<IN1,IN2,OUT>.Context ctx,
 org.apache.flink.util.Collector<OUT> out)
                                      throws Exception

This method is called for each element in the broadcast stream.

This function can output zero or more elements using the Collector parameter, query the current processing/event time, and also query and update the internal broadcast state. These can be done through the provided BroadcastProcessFunction<IN1,IN2,OUT>.Context. The context is only valid during the invocation of this method, do not store it.

Parameters:

value - The stream element.

ctx - A BroadcastProcessFunction<IN1,IN2,OUT>.Context that allows querying the timestamp of the element, querying the current processing/event time and updating the broadcast state. The context is only valid during the invocation of this method, do not store it.

out - The collector to emit resulting elements to

Throws:

Exception - The function may throw exceptions which cause the streaming program to fail and go into recovery.