Package org.apache.flink.api.common.operators.base

Class BulkIterationBase.TerminationCriterionMapper<X>

java.lang.Object

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

org.apache.flink.api.common.operators.base.BulkIterationBase.TerminationCriterionMapper<X>

All Implemented Interfaces:

Serializable, FlatMapFunction<X,X>, org.apache.flink.api.common.functions.Function, RichFunction

Enclosing class:

BulkIterationBase<T>

public static class BulkIterationBase.TerminationCriterionMapper<X>
extends AbstractRichFunction
implements FlatMapFunction<X,X>

Special Mapper that is added before a termination criterion and is only a container for an special aggregator

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
TerminationCriterionMapper()

Method Summary

Modifier and Type	Method	Description
void	flatMap(X in, Collector<X> out)	The core method of the FlatMapFunction.
void	open(OpenContext openContext)	Initialization method for the function.

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 Detail

TerminationCriterionMapper

public TerminationCriterionMapper()

Method Detail

open

public void open(OpenContext openContext)

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);
     }
 }
 

By default, this method does nothing.

1. If you implement open(OpenContext openContext), the open(OpenContext openContext) will be invoked and the open(Configuration parameters) won't be invoked. 2. If you don't implement open(OpenContext openContext), the open(Configuration parameters) will be invoked in the default implementation of the open(OpenContext openContext).

Specified by:

open in interface RichFunction

Parameters:

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

flatMap

public void flatMap(X in,
                    Collector<X> out)

Description copied from interface: FlatMapFunction

The core method of the FlatMapFunction. Takes an element from the input data set and transforms it into zero, one, or more elements.

Specified by:

flatMap in interface FlatMapFunction<X,X>

Parameters:

in - The input value.

out - The collector for returning result values.