org.apache.kafka.connect.source.SourceTask Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.connect.source;
import org.apache.kafka.connect.connector.Task;
import java.util.List;
import java.util.Map;
/**
* SourceTask is a Task that pulls records from another system for storage in Kafka.
*/
public abstract class SourceTask implements Task {
protected SourceTaskContext context;
/**
* Initialize this SourceTask with the specified context object.
*/
public void initialize(SourceTaskContext context) {
this.context = context;
}
/**
* Start the Task. This should handle any configuration parsing and one-time setup of the task.
* @param props initial configuration
*/
@Override
public abstract void start(Map props);
/**
* Poll this SourceTask for new records. This method should block if no data is currently
* available.
*
* @return a list of source records
*/
public abstract List poll() throws InterruptedException;
/**
*
* Commit the offsets, up to the offsets that have been returned by {@link #poll()}. This
* method should block until the commit is complete.
*
*
* SourceTasks are not required to implement this functionality; Kafka Connect will record offsets
* automatically. This hook is provided for systems that also need to store offsets internally
* in their own system.
*
*/
public void commit() throws InterruptedException {
// This space intentionally left blank.
}
/**
* Signal this SourceTask to stop. In SourceTasks, this method only needs to signal to the task that it should stop
* trying to poll for new data and interrupt any outstanding poll() requests. It is not required that the task has
* fully stopped. Note that this method necessarily may be invoked from a different thread than {@link #poll()} and
* {@link #commit()}.
*
* For example, if a task uses a {@link java.nio.channels.Selector} to receive data over the network, this method
* could set a flag that will force {@link #poll()} to exit immediately and invoke
* {@link java.nio.channels.Selector#wakeup() wakeup()} to interrupt any ongoing requests.
*/
public abstract void stop();
/**
*
* Commit an individual {@link SourceRecord} when the callback from the producer client is received, or if a record is filtered by a transformation.
*
*
* SourceTasks are not required to implement this functionality; Kafka Connect will record offsets
* automatically. This hook is provided for systems that also need to store offsets internally
* in their own system.
*
*
* @param record {@link SourceRecord} that was successfully sent via the producer.
* @throws InterruptedException
*/
public void commitRecord(SourceRecord record) throws InterruptedException {
// This space intentionally left blank.
}
}