Package org.apache.kafka.streams.processor.internals

Class ProcessorContextImpl

java.lang.Object

org.apache.kafka.streams.processor.internals.AbstractProcessorContext

org.apache.kafka.streams.processor.internals.ProcessorContextImpl

All Implemented Interfaces:

InternalProcessorContext, RecordCollector.Supplier, ProcessorContext

public class ProcessorContextImpl
extends AbstractProcessorContext
implements RecordCollector.Supplier

Field Summary

Fields inherited from class org.apache.kafka.streams.processor.internals.AbstractProcessorContext

cache, currentNode, NONEXIST_TOPIC, recordContext

Fields inherited from interface org.apache.kafka.streams.processor.internals.InternalProcessorContext

BYTEARRAY_VALUE_SERIALIZER, BYTES_KEY_SERIALIZER

Constructor Summary

Constructors

Constructor	Description
ProcessorContextImpl(TaskId id, StreamsConfig config, ProcessorStateManager stateMgr, StreamsMetricsImpl metrics, ThreadCache cache)

Method Summary

Modifier and Type	Method	Description
void	commit()	Requests a commit.
ProcessorNode<?,?>	currentNode()	Get the current ProcessorNode
<K,V> void	forward(K key, V value)	Forwards a key/value pair to all downstream processors.
<K,V> void	forward(K key, V value, int childIndex)	Deprecated.
<K,V> void	forward(K key, V value, java.lang.String childName)	Deprecated.
<K,V> void	forward(K key, V value, To to)	Forwards a key/value pair to the specified downstream processors.
StateStore	getStateStore(java.lang.String name)	Get the state store given the store name.
void	logChange(java.lang.String storeName, org.apache.kafka.common.utils.Bytes key, byte[] value, long timestamp)
long	offset()	Returns the offset of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call).
int	partition()	Returns the partition id of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call).
RecordCollector	recordCollector()	Get the record collector.
ProcessorRecordContext	recordContext()	Returns the current RecordContext
void	register(StateStore store, StateRestoreCallback stateRestoreCallback)	Registers and possibly restores the specified storage engine.
void	registerCacheFlushListener(java.lang.String namespace, ThreadCache.DirtyEntryFlushListener listener)	Register a dirty entry flush listener for a particular namespace
Cancellable	schedule(long intervalMs, PunctuationType type, Punctuator callback)	Deprecated.
Cancellable	schedule(java.time.Duration interval, PunctuationType type, Punctuator callback)	Schedules a periodic operation for processors.
void	setRecordContext(ProcessorRecordContext recordContext)
ProcessorStateManager	stateManager()
long	timestamp()	Returns the current timestamp.
java.lang.String	topic()	Returns the topic name of the current input record; could be null if it is not available (for example, if this method is invoked from the punctuate call).
void	transitionToActive(StreamTask streamTask, RecordCollector recordCollector, ThreadCache newCache)	Transition to active task and register a new task and cache to this processor context
void	transitionToStandby(ThreadCache newCache)	Transition to standby task and register a dummy cache to this processor context

Methods inherited from class org.apache.kafka.streams.processor.internals.AbstractProcessorContext

appConfigs, appConfigsWithPrefix, applicationId, applicationInternalStream, cache, currentSystemTimeMs, headers, initialize, keySerde, metrics, setCurrentNode, setSystemTimeMs, stateDir, taskId, taskType, uninitialize, valueSerde

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.kafka.streams.processor.internals.InternalProcessorContext

getStateStore

Constructor Detail

ProcessorContextImpl

public ProcessorContextImpl(TaskId id,
                            StreamsConfig config,
                            ProcessorStateManager stateMgr,
                            StreamsMetricsImpl metrics,
                            ThreadCache cache)

Method Detail

transitionToActive

public void transitionToActive(StreamTask streamTask,
                               RecordCollector recordCollector,
                               ThreadCache newCache)

Description copied from interface: InternalProcessorContext

Transition to active task and register a new task and cache to this processor context

Specified by:

transitionToActive in interface InternalProcessorContext

transitionToStandby

public void transitionToStandby(ThreadCache newCache)

Description copied from interface: InternalProcessorContext

Transition to standby task and register a dummy cache to this processor context

Specified by:

transitionToStandby in interface InternalProcessorContext

registerCacheFlushListener

public void registerCacheFlushListener(java.lang.String namespace,
                                       ThreadCache.DirtyEntryFlushListener listener)

Description copied from interface: InternalProcessorContext

Register a dirty entry flush listener for a particular namespace

Specified by:

registerCacheFlushListener in interface InternalProcessorContext

stateManager

public ProcessorStateManager stateManager()

register

public void register(StateStore store,
                     StateRestoreCallback stateRestoreCallback)

Description copied from interface: ProcessorContext

Registers and possibly restores the specified storage engine.

Specified by:

register in interface ProcessorContext

Overrides:

register in class AbstractProcessorContext

Parameters:

store - the storage engine

stateRestoreCallback - the restoration callback logic for log-backed state stores upon restart

recordCollector

public RecordCollector recordCollector()

Description copied from interface: RecordCollector.Supplier

Get the record collector.

Specified by:

recordCollector in interface RecordCollector.Supplier

Returns:

the record collector

logChange

public void logChange(java.lang.String storeName,
                      org.apache.kafka.common.utils.Bytes key,
                      byte[] value,
                      long timestamp)

Specified by:

logChange in interface InternalProcessorContext

getStateStore

public StateStore getStateStore(java.lang.String name)

Description copied from interface: ProcessorContext

Get the state store given the store name.

Specified by:

getStateStore in interface ProcessorContext

Parameters:

name - The store name

Returns:

The state store instance

Throws:

StreamsException - if an attempt is made to access this state store from an unknown node

java.lang.UnsupportedOperationException - if the current streamTask type is standby

forward

public <K,V> void forward(K key,
                                V value)

Description copied from interface: ProcessorContext

Forwards a key/value pair to all downstream processors. Used the input record's timestamp as timestamp for the output record.

Specified by:

forward in interface ProcessorContext

Parameters:

key - key

value - value

forward

@Deprecated
public <K,V> void forward(K key,
                                V value,
                                int childIndex)

Deprecated.

Description copied from interface: ProcessorContext

Forwards a key/value pair to one of the downstream processors designated by childIndex.

Specified by:

forward in interface ProcessorContext

Parameters:

key - key

value - value

childIndex - index in list of children of this node

forward

@Deprecated
public <K,V> void forward(K key,
                                V value,
                                java.lang.String childName)

Deprecated.

Description copied from interface: ProcessorContext

Forwards a key/value pair to one of the downstream processors designated by the downstream processor name.

Specified by:

forward in interface ProcessorContext

Parameters:

key - key

value - value

childName - name of downstream processor

forward

public <K,V> void forward(K key,
                                V value,
                                To to)

Description copied from interface: ProcessorContext

Forwards a key/value pair to the specified downstream processors. Can be used to set the timestamp of the output record.

Specified by:

forward in interface ProcessorContext

Parameters:

key - key

value - value

to - the options to use when forwarding

commit

public void commit()

Description copied from interface: ProcessorContext

Requests a commit.

Specified by:

commit in interface ProcessorContext

schedule

@Deprecated
public Cancellable schedule(long intervalMs,
                            PunctuationType type,
                            Punctuator callback)

Deprecated.

Description copied from interface: ProcessorContext

Schedules a periodic operation for processors. A processor may call this method during initialization or processing to schedule a periodic callback — called a punctuation — to Punctuator.punctuate(long). The type parameter controls what notion of time is used for punctuation:

• PunctuationType.STREAM_TIME — uses "stream time", which is advanced by the processing of messages in accordance with the timestamp as extracted by the TimestampExtractor in use. The first punctuation will be triggered by the first record that is processed. NOTE: Only advanced if messages arrive
• PunctuationType.WALL_CLOCK_TIME — uses system time (the wall-clock time), which is advanced independent of whether new messages arrive. The first punctuation will be triggered after interval has elapsed. NOTE: This is best effort only as its granularity is limited by how long an iteration of the processing loop takes to complete

Skipping punctuations: Punctuations will not be triggered more than once at any given timestamp. This means that "missed" punctuation will be skipped. It's possible to "miss" a punctuation if:

• with PunctuationType.STREAM_TIME, when stream time advances more than interval
• with PunctuationType.WALL_CLOCK_TIME, on GC pause, too short interval, ...

Specified by:

schedule in interface ProcessorContext

Parameters:

intervalMs - the time interval between punctuations in milliseconds

type - one of: PunctuationType.STREAM_TIME, PunctuationType.WALL_CLOCK_TIME

callback - a function consuming timestamps representing the current stream or system time

Returns:

a handle allowing cancellation of the punctuation schedule established by this method

schedule

public Cancellable schedule(java.time.Duration interval,
                            PunctuationType type,
                            Punctuator callback)
                     throws java.lang.IllegalArgumentException

Description copied from interface: ProcessorContext

Schedules a periodic operation for processors. A processor may call this method during initialization or processing to schedule a periodic callback — called a punctuation — to Punctuator.punctuate(long). The type parameter controls what notion of time is used for punctuation:

• PunctuationType.STREAM_TIME — uses "stream time", which is advanced by the processing of messages in accordance with the timestamp as extracted by the TimestampExtractor in use. The first punctuation will be triggered by the first record that is processed. NOTE: Only advanced if messages arrive
• PunctuationType.WALL_CLOCK_TIME — uses system time (the wall-clock time), which is advanced independent of whether new messages arrive. The first punctuation will be triggered after interval has elapsed. NOTE: This is best effort only as its granularity is limited by how long an iteration of the processing loop takes to complete

Skipping punctuations: Punctuations will not be triggered more than once at any given timestamp. This means that "missed" punctuation will be skipped. It's possible to "miss" a punctuation if:

• with PunctuationType.STREAM_TIME, when stream time advances more than interval
• with PunctuationType.WALL_CLOCK_TIME, on GC pause, too short interval, ...

Specified by:

schedule in interface ProcessorContext

Parameters:

interval - the time interval between punctuations (supported minimum is 1 millisecond)

type - one of: PunctuationType.STREAM_TIME, PunctuationType.WALL_CLOCK_TIME

callback - a function consuming timestamps representing the current stream or system time

Returns:

a handle allowing cancellation of the punctuation schedule established by this method

Throws:

java.lang.IllegalArgumentException

topic

public java.lang.String topic()

Description copied from interface: ProcessorContext

Returns the topic name of the current input record; could be null if it is not available (for example, if this method is invoked from the punctuate call).

Specified by:

topic in interface ProcessorContext

Overrides:

topic in class AbstractProcessorContext

Returns:

the topic name

partition

public int partition()

Description copied from interface: ProcessorContext

Returns the partition id of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call).

Specified by:

partition in interface ProcessorContext

Overrides:

partition in class AbstractProcessorContext

Returns:

the partition id

offset

public long offset()

Description copied from interface: ProcessorContext

Returns the offset of the current input record; could be -1 if it is not available (for example, if this method is invoked from the punctuate call).

Specified by:

offset in interface ProcessorContext

Overrides:

offset in class AbstractProcessorContext

Returns:

the offset

timestamp

public long timestamp()

Description copied from interface: ProcessorContext

Returns the current timestamp.

If it is triggered while processing a record streamed from the source processor, timestamp is defined as the timestamp of the current input record; the timestamp is extracted from ConsumerRecord by TimestampExtractor.

If it is triggered while processing a record generated not from the source processor (for example, if this method is invoked from the punctuate call), timestamp is defined as the current task's stream time, which is defined as the largest timestamp of any record processed by the task.

Specified by:

timestamp in interface ProcessorContext

Overrides:

timestamp in class AbstractProcessorContext

Returns:

the timestamp

currentNode

public ProcessorNode<?,?> currentNode()

Description copied from interface: InternalProcessorContext

Get the current ProcessorNode

Specified by:

currentNode in interface InternalProcessorContext

Overrides:

currentNode in class AbstractProcessorContext

setRecordContext

public void setRecordContext(ProcessorRecordContext recordContext)

Specified by:

setRecordContext in interface InternalProcessorContext

Overrides:

setRecordContext in class AbstractProcessorContext

Parameters:

recordContext - the ProcessorRecordContext for the record about to be processes

recordContext

public ProcessorRecordContext recordContext()

Description copied from interface: InternalProcessorContext

Returns the current RecordContext

Specified by:

recordContext in interface InternalProcessorContext

Overrides:

recordContext in class AbstractProcessorContext

Returns:

the current RecordContext