K - The type of the key based on which we join elements.T1 - The type of the elements in the left stream.T2 - The type of the elements in the right stream.OUT - The output type created by the user-defined function.@Internal public class IntervalJoinOperator<K,T1,T2,OUT> extends AbstractUdfStreamOperator<OUT,ProcessJoinFunction<T1,T2,OUT>> implements TwoInputStreamOperator<T1,T2,OUT>, Triggerable<K,String>
operator to execute time-bounded stream inner joins.
By using a configurable lower and upper bound this operator will emit exactly those pairs (T1, T2) where t2.ts ∈ [T1.ts + lowerBound, T1.ts + upperBound]. Both the lower and the upper bound can be configured to be either inclusive or exclusive.
As soon as elements are joined they are passed to a user-defined ProcessJoinFunction.
The basic idea of this implementation is as follows: Whenever we receive an element at processElement1(StreamRecord) (a.k.a. the left side), we add it to the left buffer. We then
check the right buffer to see whether there are any elements that can be joined. If there are,
they are joined and passed to the aforementioned function. The same happens the other way around
when receiving an element on the right side.
Whenever a pair of elements is emitted it will be assigned the max timestamp of either of the elements.
In order to avoid the element buffers to grow indefinitely a cleanup timer is registered per element. This timer indicates when an element is not considered for joining anymore and can be removed from the state.
| Modifier and Type | Class and Description |
|---|---|
static class |
IntervalJoinOperator.BufferEntry<T>
A container for elements put in the left/write buffer.
|
static class |
IntervalJoinOperator.BufferEntrySerializer<T>
A
serializer for the IntervalJoinOperator.BufferEntry. |
static class |
IntervalJoinOperator.BufferEntrySerializerSnapshot<T>
|
userFunctionchainingStrategy, config, latencyStats, LOG, metrics, output, processingTimeService| Constructor and Description |
|---|
IntervalJoinOperator(long lowerBound,
long upperBound,
boolean lowerBoundInclusive,
boolean upperBoundInclusive,
OutputTag<T1> leftLateDataOutputTag,
OutputTag<T2> rightLateDataOutputTag,
TypeSerializer<T1> leftTypeSerializer,
TypeSerializer<T2> rightTypeSerializer,
ProcessJoinFunction<T1,T2,OUT> udf)
Creates a new IntervalJoinOperator.
|
| Modifier and Type | Method and Description |
|---|---|
void |
initializeState(StateInitializationContext context)
Stream operators with state which can be restored need to override this hook method.
|
void |
onEventTime(InternalTimer<K,String> timer)
Invoked when an event-time timer fires.
|
void |
onProcessingTime(InternalTimer<K,String> timer)
Invoked when a processing-time timer fires.
|
void |
open()
This method is called immediately before any elements are processed, it should contain the
operator's initialization logic, e.g.
|
void |
processElement1(StreamRecord<T1> record)
Process a
StreamRecord from the left stream. |
void |
processElement2(StreamRecord<T2> record)
Process a
StreamRecord from the right stream. |
protected <T> void |
sideOutput(T value,
long timestamp,
boolean isLeft)
Write skipped late arriving element to SideOutput.
|
close, finish, getUserFunction, getUserFunctionParameters, notifyCheckpointAborted, notifyCheckpointComplete, setOutputType, setup, snapshotStategetChainingStrategy, getContainingTask, getCurrentKey, getExecutionConfig, getInternalTimerService, getKeyedStateBackend, getKeyedStateStore, getMetricGroup, getOperatorConfig, getOperatorID, getOperatorName, getOperatorStateBackend, getOrCreateKeyedState, getPartitionedState, getPartitionedState, getProcessingTimeService, getRuntimeContext, getTimeServiceManager, getUserCodeClassloader, hasKeyContext1, hasKeyContext2, initializeState, isUsingCustomRawKeyedState, prepareSnapshotPreBarrier, processLatencyMarker, processLatencyMarker1, processLatencyMarker2, processWatermark, processWatermark1, processWatermark2, processWatermarkStatus, processWatermarkStatus1, processWatermarkStatus2, reportOrForwardLatencyMarker, setChainingStrategy, setCurrentKey, setKeyContextElement1, setKeyContextElement2, setProcessingTimeService, snapshotStateclone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitprocessLatencyMarker1, processLatencyMarker2, processWatermark1, processWatermark2, processWatermarkStatus1, processWatermarkStatus2close, finish, getMetricGroup, getOperatorID, initializeState, prepareSnapshotPreBarrier, setKeyContextElement1, setKeyContextElement2, snapshotStatenotifyCheckpointAborted, notifyCheckpointCompletegetCurrentKey, setCurrentKeyhasKeyContextpublic IntervalJoinOperator(long lowerBound,
long upperBound,
boolean lowerBoundInclusive,
boolean upperBoundInclusive,
OutputTag<T1> leftLateDataOutputTag,
OutputTag<T2> rightLateDataOutputTag,
TypeSerializer<T1> leftTypeSerializer,
TypeSerializer<T2> rightTypeSerializer,
ProcessJoinFunction<T1,T2,OUT> udf)
lowerBound - The lower bound for evaluating if elements should be joinedupperBound - The upper bound for evaluating if elements should be joinedlowerBoundInclusive - Whether or not to include elements where the timestamp matches the
lower boundupperBoundInclusive - Whether or not to include elements where the timestamp matches the
upper boundudf - A user-defined ProcessJoinFunction that gets called whenever two elements
of T1 and T2 are joinedpublic void open()
throws Exception
AbstractStreamOperatorThe default implementation does nothing.
open in interface StreamOperator<OUT>open in class AbstractUdfStreamOperator<OUT,ProcessJoinFunction<T1,T2,OUT>>Exception - An exception in this method causes the operator to fail.public void initializeState(StateInitializationContext context) throws Exception
AbstractStreamOperatorinitializeState in interface StreamOperatorStateHandler.CheckpointedStreamOperatorinitializeState in class AbstractUdfStreamOperator<OUT,ProcessJoinFunction<T1,T2,OUT>>context - context that allows to register different states.Exceptionpublic void processElement1(StreamRecord<T1> record) throws Exception
StreamRecord from the left stream. Whenever an StreamRecord arrives
at the left stream, it will get added to the left buffer. Possible join candidates for that
element will be looked up from the right buffer and if the pair lies within the user defined
boundaries, it gets passed to the ProcessJoinFunction.processElement1 in interface TwoInputStreamOperator<T1,T2,OUT>record - An incoming record to be joinedException - Can throw an Exception during state accesspublic void processElement2(StreamRecord<T2> record) throws Exception
StreamRecord from the right stream. Whenever a StreamRecord arrives
at the right stream, it will get added to the right buffer. Possible join candidates for that
element will be looked up from the left buffer and if the pair lies within the user defined
boundaries, it gets passed to the ProcessJoinFunction.processElement2 in interface TwoInputStreamOperator<T1,T2,OUT>record - An incoming record to be joinedException - Can throw an exception during state accessprotected <T> void sideOutput(T value,
long timestamp,
boolean isLeft)
public void onEventTime(InternalTimer<K,String> timer) throws Exception
TriggerableonEventTime in interface Triggerable<K,String>Exceptionpublic void onProcessingTime(InternalTimer<K,String> timer) throws Exception
TriggerableonProcessingTime in interface Triggerable<K,String>ExceptionCopyright © 2014–2024 The Apache Software Foundation. All rights reserved.