com.continuent.tungsten.replicator.extractor
Interface RawExtractor

All Superinterfaces:

ReplicatorPlugin

All Known Implementing Classes:

CSVLoader, DummyExtractor, JdbcLoader, Loader, MySQLExtractor, MySQLLoader, OracleCDCExtractor, OracleCDCReaderExtractor, OracleExtractor, PostgreSQLSlonyExtractor

public interface RawExtractor
extends ReplicatorPlugin

Denotes an extractor that is responsible for extracting raw events from a database or other replication source. Extractors must be prepared to be interrupted, which mechanism is used to cancel processing.

Version:

1.0

Author:

Teemu Ollakka

Method Summary

DBMSEvent	extract() Extract the next available DBMSEvent from the database log.
DBMSEvent	extract(java.lang.String eventId) Extract starting after the event ID provided as an argument.
java.lang.String	getCurrentResourceEventId() Returns the last event ID committed in the database from which we are extracting.
void	setLastEventId(java.lang.String eventId) Set the value of the last event ID we have processed.

Methods inherited from interface com.continuent.tungsten.replicator.plugin.ReplicatorPlugin

configure, prepare, release

Method Detail

setLastEventId

void setLastEventId(java.lang.String eventId)
                    throws ReplicatorException

Set the value of the last event ID we have processed. The extractor is responsible for returning the next event ID in sequence after this one the next time extract() is called.

Parameters:

eventId - Event ID at which to begin extracting

Throws:

ReplicatorException

extract

DBMSEvent extract()
                  throws ReplicatorException,
                         java.lang.InterruptedException

Extract the next available DBMSEvent from the database log.

Returns:

next DBMSEvent found in the logs

Throws:

ReplicatorException

java.lang.InterruptedException

extract

DBMSEvent extract(java.lang.String eventId)
                  throws ReplicatorException,
                         java.lang.InterruptedException

Extract starting after the event ID provided as an argument. This is equivalent to invoking setLastEventId() followed by extract().

Parameters:

eventId - Event ID at which to begin extracting

Returns:

DBMSEvent corresponding to the id

Throws:

ReplicatorException - Thrown if extractor processing fails

java.lang.InterruptedException - Thrown if the applier is interrupted

getCurrentResourceEventId

java.lang.String getCurrentResourceEventId()
                                           throws ReplicatorException,
                                                  java.lang.InterruptedException

Returns the last event ID committed in the database from which we are extracting. It is used to help synchronize state between the database and the transaction history log. Values returned from this call must correspond with the last extracted DBMSEvent.eventId as follows:

1. If the returned value is greater than DBMSEvent.eventId, the database has more recent updates
2. If the returned value is equal to DBMSEvent.eventId, all events have been extracted

It should not be possible to receive a value that is less than the last extracted DBMSEvent.eventId as this implies that the extractor is somehow ahead of the state of the database, which would be inconsistent.

Returns:

A current event ID that can be compared with event IDs in DBMSEvent

Throws:

ReplicatorException

java.lang.InterruptedException