org.apache.tez.runtime.api

Class AbstractLogicalInput

java.lang.Object

org.apache.tez.runtime.api.AbstractLogicalInput

All Implemented Interfaces:

Input, InputFrameworkInterface, LogicalInput, LogicalInputFrameworkInterface

@InterfaceAudience.Public
public abstract class AbstractLogicalInput
extends Object
implements LogicalInput, LogicalInputFrameworkInterface

An abstract class which should be the base class for all implementations of LogicalInput. This class implements the framework facing as well as user facing methods which need to be implemented by all LogicalInputs. This includes default implementations of a new method for convenience. Input classes must provide a 2 argument public constructor for Tez to create the Input. The parameters to this constructor are 1) an instance of InputContext and 2) an integer which is used to setup the number of physical inputs that the logical input will see. Tez will take care of initializing and closing the Input after a Processor completes.

Constructor Summary

Constructors

Constructor and Description
AbstractLogicalInput(InputContext inputContext, int numPhysicalInputs) Constructor an instance of the LogicalInput.

Method Summary

Methods

Modifier and Type	Method and Description
InputContext	getContext() Return ahe InputContext for this specific instance of the LogicalInput
int	getNumPhysicalInputs() Get the number of physical inputs that this LogicalInput will receive.
abstract List<Event>	initialize() Initializes the Input.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.tez.runtime.api.Input

getReader, start

Methods inherited from interface org.apache.tez.runtime.api.InputFrameworkInterface

close, handleEvents

Constructor Detail

AbstractLogicalInput

public AbstractLogicalInput(InputContext inputContext,
                    int numPhysicalInputs)

Constructor an instance of the LogicalInput. Classes extending this one to create a LogicalInput, must provide the same constructor so that Tez can create an instance of the class at runtime.

Parameters:

inputContext - the InputContext which provides the Input with context information within the running task.

numPhysicalInputs - the number of physical inputs that the logical input will receive. This is typically determined by Edge Routing.

Method Detail

initialize

public abstract List<Event> initialize()
                                throws Exception

Description copied from interface: InputFrameworkInterface

Initializes the Input.

Specified by:

initialize in interface InputFrameworkInterface

Returns:

list of events that were generated during initialization

Throws:

Exception - if an error occurs

getNumPhysicalInputs

public final int getNumPhysicalInputs()

Get the number of physical inputs that this LogicalInput will receive. This is typically determined by Edge routing, and number of upstream tasks

Returns:

the number of physical inputs

getContext

public final InputContext getContext()

Return ahe InputContext for this specific instance of the LogicalInput

Returns:

the InputContext for the input