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 AtomicReference<Throwable>	error
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)
Throwable	getError()	Returns error that occurred during event fetching
boolean	hasError()	Indicates whether an error occurred during event fetching
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

error

private final AtomicReference<Throwable> error

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

hasError

public boolean hasError()

Indicates whether an error occurred during event fetching

Returns:

true if error occurred, false otherwise

getError

public Throwable getError()

Returns error that occurred during event fetching

Returns:

error or null if no error occurred

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