com.aliyun.odps.udf

Class UDJ

java.lang.Object

com.aliyun.odps.udf.UDJ

public abstract class UDJ
extends Object

UDJ (User Defined Join)

User Defined Join need to inherit this class to implement a UDJ, override join method

Constructor Summary

Constructors

Constructor and Description
UDJ()

Method Summary

Modifier and Type	Method and Description
abstract void	close() Interface for operations upon udj exit, implementation can be no-op
abstract void	join(Record key, Iterator<Record> left, Iterator<Record> right, Yieldable<Record> output) Interface for setting up the udj, implementation can be a no-op
abstract void	setup(ExecutionContext ctx, DataAttributes attributes) Interface for setting up the udj, implementation can be a no-op

Methods inherited from class java.lang.Object

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

Constructor Detail

UDJ

public UDJ()

Method Detail

setup

public abstract void setup(ExecutionContext ctx,
                           DataAttributes attributes)

Interface for setting up the udj, implementation can be a no-op

Parameters:

ctx: - the ExecutionContext which contains context information that may be useful for setting up user code execution environment

attributes: - encapsulate any attributes needed for join operation, such as parameters described by k-v pairs

join

public abstract void join(Record key,
                          Iterator<Record> left,
                          Iterator<Record> right,
                          Yieldable<Record> output)

Interface for setting up the udj, implementation can be a no-op

Parameters:

key: - join key

left: - left input records, if map join hint is used (on smaller table), left input will correspond to the table on which the map join hint is applied: i.e., left input corresponds to smaller table in that case

right: - right input records, in the case of map join, right input would provide the streaming input from the larger table that likely would not fit into memory as a whole

output: - interaface for producing output from the joining operation

close

public abstract void close()

Interface for operations upon udj exit, implementation can be no-op