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

Class ReduceApplyProcessWindowFunction<K,W extends Window,T,R>

java.lang.Object

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

org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction<T,R,K,W>

org.apache.flink.streaming.api.functions.windowing.ReduceApplyProcessWindowFunction<K,W,T,R>

All Implemented Interfaces:

Serializable, Function, RichFunction

@Internal
public class ReduceApplyProcessWindowFunction<K,W extends Window,T,R>
extends ProcessWindowFunction<T,R,K,W>

Internal ProcessWindowFunction that is used for implementing a fold on a window configuration that only allows AllWindowFunction and cannot directly execute a ReduceFunction.

See Also:

Serialized Form

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.flink.streaming.api.functions.windowing.ProcessWindowFunction

ProcessWindowFunction.Context

Constructor Summary

Constructors

Constructor	Description
ReduceApplyProcessWindowFunction(ReduceFunction<T> reduceFunction, ProcessWindowFunction<T,R,K,W> windowFunction)

Method Summary

Modifier and Type	Method	Description
void	clear(ProcessWindowFunction.Context context)	Deletes any state in the Context when the Window expires (the watermark passes its maxTimestamp + allowedLateness).
void	close()	Tear-down method for the user code.
void	open(OpenContext openContext)	Initialization method for the function.
void	process(K k, ProcessWindowFunction.Context context, Iterable<T> input, Collector<R> out)	Evaluates the window and outputs none or several elements.
void	setRuntimeContext(RuntimeContext t)	Sets the function's runtime context.

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

getIterationRuntimeContext, getRuntimeContext

Methods inherited from class java.lang.Object

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

Constructor Detail

ReduceApplyProcessWindowFunction

public ReduceApplyProcessWindowFunction(ReduceFunction<T> reduceFunction,
                                        ProcessWindowFunction<T,R,K,W> windowFunction)

Method Detail

process

public void process(K k,
                    ProcessWindowFunction.Context context,
                    Iterable<T> input,
                    Collector<R> out)
             throws Exception

Description copied from class: ProcessWindowFunction

Evaluates the window and outputs none or several elements.

Specified by:

process in class ProcessWindowFunction<T,R,K,W extends Window>

Parameters:

k - The key for which this window is evaluated.

context - The context in which the window is being evaluated.

input - The elements in the window being evaluated.

out - A collector for emitting elements.

Throws:

Exception - The function may throw exceptions to fail the program and trigger recovery.

clear

public void clear(ProcessWindowFunction.Context context)
           throws Exception

Description copied from class: ProcessWindowFunction

Deletes any state in the Context when the Window expires (the watermark passes its maxTimestamp + allowedLateness).

Overrides:

clear in class ProcessWindowFunction<T,R,K,W extends Window>

Parameters:

context - The context to which the window is being evaluated

Throws:

Exception - The function may throw exceptions to fail the program and trigger recovery.

open

public void open(OpenContext openContext)
          throws Exception

Description copied from interface: RichFunction

Initialization method for the function. It is called before the actual working methods (like map or join) and thus suitable for one time setup work. For functions that are part of an iteration, this method will be invoked at the beginning of each iteration superstep.

The openContext object passed to the function can be used for configuration and initialization. The openContext contains some necessary information that were configured on the function in the program composition.

 public class MyFilter extends RichFilterFunction<String> {

     private String searchString;

     public void open(OpenContext openContext) {
         // initialize the value of searchString
     }

     public boolean filter(String value) {
         return value.equals(searchString);
     }
 }
 

Specified by:

open in interface RichFunction

Overrides:

open in class AbstractRichFunction

Parameters:

openContext - The context containing information about the context in which the function is opened.

Throws:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.

close

public void close()
           throws Exception

Description copied from interface: RichFunction

Tear-down method for the user code. It is called after the last call to the main working methods (e.g. map or join). For functions that are part of an iteration, this method will be invoked after each iteration superstep.

This method can be used for clean up work.

Specified by:

close in interface RichFunction

Overrides:

close in class AbstractRichFunction

Throws:

Exception - Implementations may forward exceptions, which are caught by the runtime. When the runtime catches an exception, it aborts the task and lets the fail-over logic decide whether to retry the task execution.

setRuntimeContext

public void setRuntimeContext(RuntimeContext t)

Description copied from interface: RichFunction

Sets the function's runtime context. Called by the framework when creating a parallel instance of the function.

Specified by:

setRuntimeContext in interface RichFunction

Overrides:

setRuntimeContext in class AbstractRichFunction

Parameters:

t - The runtime context.