io.debezium.connector.mysql

Class AbstractReader

java.lang.Object

io.debezium.connector.mysql.AbstractReader

Direct Known Subclasses:

BinlogReader, SnapshotReader

public abstract class AbstractReader
extends Object

A component that performs a snapshot of a MySQL server, and records the schema changes in MySqlSchema.

Author:

Randall Hauch

Field Summary

Fields

Modifier and Type	Field and Description
protected MySqlTaskContext	context
private AtomicReference<org.apache.kafka.connect.errors.ConnectException>	failure
private org.apache.kafka.connect.errors.ConnectException	failureException
protected org.slf4j.Logger	logger
private int	maxBatchSize
private Metronome	metronome
private BlockingQueue<org.apache.kafka.connect.source.SourceRecord>	records
private AtomicBoolean	running
private AtomicBoolean	success

Constructor Summary

Constructors

Constructor and Description
AbstractReader(MySqlTaskContext context) Create a snapshot reader.

Method Summary

Modifier and Type	Method and Description
protected void	completeSuccessfully() Call this method only when the reader has successfully completed all of its work, signaling that subsequent calls to poll() should forever return null.
protected abstract void	doCleanup() The reader has completed sending all enqueued records, so clean up any resources that remain.
protected abstract void	doStart() The reader has been requested to start, so initialize any resources required by the reader.
protected abstract void	doStop() The reader has been requested to stop, so perform any work required to stop the reader's resources that were previously started..
protected void	enqueueRecord(org.apache.kafka.connect.source.SourceRecord record) Enqueue a record so that it can be obtained when this reader is polled.
protected void	failed(Throwable error) Call this method only when the reader has failed, and that a subsequent call to poll() should throw this error.
protected void	failed(Throwable error, String msg) Call this method only when the reader has failed, and that a subsequent call to poll() should throw this error.
boolean	isRunning() Get whether the snapshot is still running and records are available.
List<org.apache.kafka.connect.source.SourceRecord>	poll() Poll for the next batch of source records.
void	start() Start the reader and return immediately.
void	stop() Stop the snapshot from running.
protected org.apache.kafka.connect.errors.ConnectException	wrap(Throwable error) Wraps the specified exception in a ConnectException, ensuring that all useful state is captured inside the new exception's message.

Methods inherited from class java.lang.Object

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

Field Detail

logger

protected final org.slf4j.Logger logger

context

protected final MySqlTaskContext context

records

private final BlockingQueue<org.apache.kafka.connect.source.SourceRecord> records

running

private final AtomicBoolean running

success

private final AtomicBoolean success

failure

private final AtomicReference<org.apache.kafka.connect.errors.ConnectException> failure

failureException

private org.apache.kafka.connect.errors.ConnectException failureException

maxBatchSize

private final int maxBatchSize

metronome

private final Metronome metronome

Constructor Detail

AbstractReader

public AbstractReader(MySqlTaskContext context)

Create a snapshot reader.

Parameters:

context - the task context in which this reader is running; may not be null

Method Detail

start

public void start()

Start the reader and return immediately. Once started, the SourceRecord can be obtained by periodically calling poll() until that method returns null.

This method does nothing if it is already running.

stop

public void stop()

Stop the snapshot from running.

This method does nothing if the snapshot is not running.

doStart

protected abstract void doStart()

The reader has been requested to start, so initialize any resources required by the reader.

doStop

protected abstract void doStop()

The reader has been requested to stop, so perform any work required to stop the reader's resources that were previously started..

doCleanup

protected abstract void doCleanup()

The reader has completed sending all enqueued records, so clean up any resources that remain.

completeSuccessfully

protected void completeSuccessfully()

Call this method only when the reader has successfully completed all of its work, signaling that subsequent calls to poll() should forever return null.

failed

protected void failed(Throwable error)

Call this method only when the reader has failed, and that a subsequent call to poll() should throw this error.

Parameters:

error - the error that resulted in the failure; should not be null

failed

protected void failed(Throwable error,
                      String msg)

Call this method only when the reader has failed, and that a subsequent call to poll() should throw this error.

Parameters:

error - the error that resulted in the failure; should not be null

msg - the error message; may not be null

wrap

protected org.apache.kafka.connect.errors.ConnectException wrap(Throwable error)

Wraps the specified exception in a ConnectException, ensuring that all useful state is captured inside the new exception's message.

Parameters:

error - the exception; may not be null

Returns:

the wrapped Kafka Connect exception

isRunning

public boolean isRunning()

Get whether the snapshot is still running and records are available.

Returns:

true if still running, or false if no longer running and/or all records have been processed

poll

public List<org.apache.kafka.connect.source.SourceRecord> poll()
                                                        throws InterruptedException

Poll for the next batch of source records. This method blocks if the snapshot is still but no records are available.

Returns:

the list of source records; or null when the snapshot is complete, all records have previously been returned, and the completion function (supplied in the constructor) has been called

Throws:

InterruptedException - if this thread is interrupted while waiting for more records

org.apache.kafka.connect.errors.ConnectException - if there is an error while this reader is running

enqueueRecord

protected void enqueueRecord(org.apache.kafka.connect.source.SourceRecord record)
                      throws InterruptedException

Enqueue a record so that it can be obtained when this reader is polled. This method will block if the queue is full.

Parameters:

record - the record to be enqueued

Throws:

InterruptedException - if interrupted while waiting for the queue to have room for this record