org.apache.hadoop.mapred

接口 Reporter

所有超级接口:

Progressable

所有已知实现类:

Task.TaskReporter

public interface Reporter
extends Progressable

A facility for Map-Reduce applications to report progress and update counters, status information etc.

Mapper and Reducer can use the Reporter provided to report progress or just indicate that they are alive. In scenarios where the application takes an insignificant amount of time to process individual key/value pairs, this is crucial since the framework might assume that the task has timed-out and kill that task.

Applications can also update Counters via the provided Reporter .

另请参阅:

Progressable, Counters

字段概要

字段

限定符和类型	字段和说明
static Reporter	NULL A constant of Reporter type that does nothing.

方法概要

方法

限定符和类型	方法和说明
Counters.Counter	getCounter(Enum<?> name) Get the Counters.Counter of the given group with the given name.
Counters.Counter	getCounter(String group, String name) Get the Counters.Counter of the given group with the given name.
InputSplit	getInputSplit() Get the InputSplit object for a map.
float	getProgress() Get the progress of the task.
void	incrCounter(Enum<?> key, long amount) Increments the counter identified by the key, which can be of any Enum type, by the specified amount.
void	incrCounter(String group, String counter, long amount) Increments the counter identified by the group and counter name by the specified amount.
void	setStatus(String status) Set the status description for the task.

从接口继承的方法 org.apache.hadoop.util.Progressable

progress

字段详细资料

NULL

static final Reporter NULL

A constant of Reporter type that does nothing.

方法详细资料

setStatus

void setStatus(String status)

Set the status description for the task.

参数:

status - brief description of the current status.

getCounter

Counters.Counter getCounter(Enum<?> name)

Get the Counters.Counter of the given group with the given name.

参数:

name - counter name

返回:

the Counter of the given group/name.

getCounter

Counters.Counter getCounter(String group,
                          String name)

Get the Counters.Counter of the given group with the given name.

参数:

group - counter group

name - counter name

返回:

the Counter of the given group/name.

incrCounter

void incrCounter(Enum<?> key,
               long amount)

Increments the counter identified by the key, which can be of any Enum type, by the specified amount.

参数:

key - key to identify the counter to be incremented. The key can be be any Enum.

amount - A non-negative amount by which the counter is to be incremented.

incrCounter

void incrCounter(String group,
               String counter,
               long amount)

Increments the counter identified by the group and counter name by the specified amount.

参数:

group - name to identify the group of the counter to be incremented.

counter - name to identify the counter within the group.

amount - A non-negative amount by which the counter is to be incremented.

getInputSplit

InputSplit getInputSplit()
                         throws UnsupportedOperationException

Get the InputSplit object for a map.

返回:

the InputSplit that the map is reading from.

抛出:

UnsupportedOperationException - if called outside a mapper

getProgress

float getProgress()

Get the progress of the task. Progress is represented as a number between 0 and 1 (inclusive).