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

Class PartitionCustomKeySelector

java.lang.Object

org.apache.flink.streaming.api.functions.python.PartitionCustomKeySelector

All Implemented Interfaces:

Serializable, Function, KeySelector<Row,Integer>

@Internal
public class PartitionCustomKeySelector
extends Object
implements KeySelector<Row,Integer>

The PartitionCustomKeySelector will return the first field of the input row value. The value of the first field is the desired partition index which is computed according to user defined partitioner and keySelector function.

See Also:

Serialized Form

Constructor Summary

Constructors

Constructor	Description
PartitionCustomKeySelector()

Method Summary

Modifier and Type	Method	Description
Integer	getKey(Row value)	User-defined function that deterministically extracts the key from an object.

Methods inherited from class java.lang.Object

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

Constructor Detail

PartitionCustomKeySelector

public PartitionCustomKeySelector()

Method Detail

getKey

public Integer getKey(Row value)
               throws Exception

Description copied from interface: KeySelector

User-defined function that deterministically extracts the key from an object.

For example for a class:

        public class Word {
                String word;
                int count;
        }
 

The key extractor could return the word as a key to group all Word objects by the String they contain.

The code would look like this

        public String getKey(Word w) {
                return w.word;
        }
 

Specified by:

getKey in interface KeySelector<Row,Integer>

Parameters:

value - The object to get the key from.

Returns:

The extracted key.

Throws:

Exception - Throwing an exception will cause the execution of the respective task to fail, and trigger recovery or cancellation of the program.