org.apache.samza.task

Interface TaskContext

public interface TaskContext

A TaskContext provides resources about the StreamTask, particularly during initialization in an InitableTask.

Method Summary

Modifier and Type	Method and Description
<K> void	deleteTimer(K key) Delete the keyed timer in this task.
MetricsRegistry	getMetricsRegistry()
SamzaContainerContext	getSamzaContainerContext()
java.lang.Object	getStore(java.lang.String name)
java.util.Set<SystemStreamPartition>	getSystemStreamPartitions()
Table	getTable(java.lang.String tableId)
TaskName	getTaskName()
default java.lang.Object	getUserContext() Gets the user-defined context.
<K> void	registerTimer(K key, long timestamp, TimerCallback<K> callback) Register a keyed timer with a callback of TimerCallback in this task.
void	setStartingOffset(SystemStreamPartition ssp, java.lang.String offset) Set the starting offset for the given SystemStreamPartition.
default void	setUserContext(java.lang.Object context) Sets the user-defined context.

Method Detail

getMetricsRegistry

MetricsRegistry getMetricsRegistry()

getSystemStreamPartitions

java.util.Set<SystemStreamPartition> getSystemStreamPartitions()

getStore

java.lang.Object getStore(java.lang.String name)

getTable

Table getTable(java.lang.String tableId)

getTaskName

TaskName getTaskName()

getSamzaContainerContext

SamzaContainerContext getSamzaContainerContext()

setStartingOffset

void setStartingOffset(SystemStreamPartition ssp,
                       java.lang.String offset)

Set the starting offset for the given SystemStreamPartition. Offsets can only be set for a SystemStreamPartition assigned to this task (as returned by getSystemStreamPartitions()); trying to set the offset for any other partition will have no effect. NOTE: this feature is experimental, and the API may change in a future release.

Parameters:

ssp - SystemStreamPartition whose offset should be set

offset - to set for the given SystemStreamPartition

setUserContext

default void setUserContext(java.lang.Object context)

Sets the user-defined context.

Parameters:

context - the user-defined context to set

getUserContext

default java.lang.Object getUserContext()

Gets the user-defined context.

Returns:

the user-defined context if set, else null

registerTimer

<K> void registerTimer(K key,
                       long timestamp,
                       TimerCallback<K> callback)

Register a keyed timer with a callback of TimerCallback in this task. The callback will be invoked exclusively with any other operations for this task, e.g. processing, windowing and commit.

Type Parameters:

K - type of the key

Parameters:

key - timer key

timestamp - epoch time when the timer will be fired, in milliseconds

callback - callback when the timer is fired

deleteTimer

<K> void deleteTimer(K key)

Delete the keyed timer in this task. Deletion only happens if the timer hasn't been fired. Otherwise it will not interrupt.

Type Parameters:

K - type of the key

Parameters:

key - timer key