Package io.debezium.connector.mongodb.events

Class BufferingChangeStreamCursor.EventFetcher<TResult>

java.lang.Object

io.debezium.connector.mongodb.events.BufferingChangeStreamCursor.EventFetcher<TResult>

Type Parameters:

TResult -

All Implemented Interfaces:

Closeable, AutoCloseable, Runnable

Enclosing class:

BufferingChangeStreamCursor<TResult>

public static final class BufferingChangeStreamCursor.EventFetcher<TResult>
extends Object
implements Runnable, Closeable

Runnable responsible for fetching events from ChangeStreamIterable and buffering them in provided queue;

This utilises standard cursors returned by ChangeStreamIterable.cursor()

Field Summary

Fields

Modifier and Type	Field	Description
private final Semaphore	capacity
private final Clock	clock
private final AtomicReference<com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>>>	cursorRef
private final MongoDbStreamingChangeEventSourceMetrics	metrics
private int	noMessageIterations
private final Queue<BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult>>	queue
static final long	QUEUE_OFFER_TIMEOUT_MS
private final AtomicBoolean	running
private final com.mongodb.client.ChangeStreamIterable<TResult>	stream
private final DelayStrategy	throttler

Constructor Summary

Constructors

Constructor	Description
EventFetcher(com.mongodb.client.ChangeStreamIterable<TResult> stream, int capacity, MongoDbStreamingChangeEventSourceMetrics metrics, Clock clock, DelayStrategy throttler)
EventFetcher(com.mongodb.client.ChangeStreamIterable<TResult> stream, int capacity, MongoDbStreamingChangeEventSourceMetrics metrics, Clock clock, Duration throttleMaxSleep)

Method Summary

Modifier and Type	Method	Description
void	close()
private boolean	enqueue(BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult> event)
private Optional<BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult>>	fetchEvent(com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>> cursor)
private void	fetchEvents(com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>> cursor)
boolean	isEmpty()
boolean	isRunning()	Indicates whether event fetching is running and the internal cursor is open
BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult>	poll()
void	run()
int	size()	Depending on queue implementation this method may not be reliable By default see ConcurrentLinkedQueue.size()
private void	throttleIfNeeded(com.mongodb.client.model.changestream.ChangeStreamDocument<TResult> document)

Methods inherited from class java.lang.Object

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

Field Details

QUEUE_OFFER_TIMEOUT_MS

public static final long QUEUE_OFFER_TIMEOUT_MS

See Also:

• Constant Field Values

stream

private final com.mongodb.client.ChangeStreamIterable<TResult> stream

capacity

private final Semaphore capacity

queue

private final Queue<BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult>> queue

throttler

private final DelayStrategy throttler

running

private final AtomicBoolean running

cursorRef

private final AtomicReference<com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>>> cursorRef

metrics

private final MongoDbStreamingChangeEventSourceMetrics metrics

clock

private final Clock clock

noMessageIterations

private int noMessageIterations

Constructor Details

EventFetcher

public EventFetcher(com.mongodb.client.ChangeStreamIterable<TResult> stream,
 int capacity,
 MongoDbStreamingChangeEventSourceMetrics metrics,
 Clock clock,
 DelayStrategy throttler)

EventFetcher

public EventFetcher(com.mongodb.client.ChangeStreamIterable<TResult> stream,
 int capacity,
 MongoDbStreamingChangeEventSourceMetrics metrics,
 Clock clock,
 Duration throttleMaxSleep)

Method Details

isRunning

public boolean isRunning()

Indicates whether event fetching is running and the internal cursor is open

Returns:

true if running, false otherwise

close

public void close()

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

poll

public BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult> poll()

isEmpty

public boolean isEmpty()

size

public int size()

Depending on queue implementation this method may not be reliable By default see ConcurrentLinkedQueue.size()

Returns:

approximate number of elements in queue

run

public void run()

Specified by:

run in interface Runnable

fetchEvents

private void fetchEvents(com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>> cursor)
                  throws InterruptedException

Throws:

InterruptedException

fetchEvent

private Optional<BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult>> fetchEvent(com.mongodb.client.MongoChangeStreamCursor<com.mongodb.client.model.changestream.ChangeStreamDocument<TResult>> cursor)

throttleIfNeeded

private void throttleIfNeeded(com.mongodb.client.model.changestream.ChangeStreamDocument<TResult> document)

enqueue

private boolean enqueue(BufferingChangeStreamCursor.ResumableChangeStreamEvent<TResult> event)
                 throws InterruptedException

Throws:

InterruptedException