Package org.apache.flink.test

Class StatefulStreamingJob.MyStatefulFunction

java.lang.Object

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

org.apache.flink.api.common.functions.RichMapFunction<Integer,String>

org.apache.flink.test.StatefulStreamingJob.MyStatefulFunction

All Implemented Interfaces:

Serializable, Function, MapFunction<Integer,String>, RichFunction

Enclosing class:

StatefulStreamingJob

public static class StatefulStreamingJob.MyStatefulFunction
extends RichMapFunction<Integer,String>

A stateful RichMapFunction that keeps the required types of state. That is:

1. an Avro,
2. a Tuple2, and
3. an Either type.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
MyStatefulFunction()

Method Summary

Modifier and Type	Method	Description
String	map(Integer value)	The mapping method.
void	open(OpenContext openContext)	Initialization method for the function.

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

close, getIterationRuntimeContext, getRuntimeContext, setRuntimeContext

Methods inherited from class java.lang.Object

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

Constructor Detail

MyStatefulFunction

public MyStatefulFunction()

Method Detail

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.

map

public String map(Integer value)
           throws Exception

Description copied from interface: MapFunction

The mapping method. Takes an element from the input data set and transforms it into exactly one element.

Specified by:

map in interface MapFunction<Integer,String>

Specified by:

map in class RichMapFunction<Integer,String>

Parameters:

value - The input value.

Returns:

The transformed value

Throws:

Exception - This method may throw exceptions. Throwing an exception will cause the operation to fail and may trigger recovery.