| /** |
| * 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.pulsar.io.kafka; |
| |
| import java.util.concurrent.LinkedBlockingQueue; |
| import org.apache.pulsar.functions.api.Record; |
| import org.apache.pulsar.io.core.Source; |
| |
| /** |
| * Kafka Push Source. |
| * To maintain compatibility, we can't pick the PIP-281: https://github.com/apache/pulsar/pull/20807 |
| * cherry-pick to the historical version, so the class is implemented in the kafka connector. |
| */ |
| public abstract class KafkaPushSource<T> implements Source<T> { |
| |
| private static class NullRecord implements Record { |
| @Override |
| public Object getValue() { |
| return null; |
| } |
| } |
| |
| private static class ErrorNotifierRecord implements Record { |
| private Exception e; |
| public ErrorNotifierRecord(Exception e) { |
| this.e = e; |
| } |
| @Override |
| public Object getValue() { |
| return null; |
| } |
| |
| public Exception getException() { |
| return e; |
| } |
| } |
| |
| private LinkedBlockingQueue<Record<T>> queue; |
| private static final int DEFAULT_QUEUE_LENGTH = 1000; |
| private final NullRecord nullRecord = new NullRecord(); |
| |
| public KafkaPushSource() { |
| this.queue = new LinkedBlockingQueue<>(this.getQueueLength()); |
| } |
| |
| @Override |
| public Record<T> read() throws Exception { |
| Record<T> record = queue.take(); |
| if (record instanceof ErrorNotifierRecord) { |
| throw ((ErrorNotifierRecord) record).getException(); |
| } |
| if (record instanceof NullRecord) { |
| return null; |
| } else { |
| return record; |
| } |
| } |
| |
| /** |
| * Send this message to be written to Pulsar. |
| * Pass null if you you are done with this task |
| * @param record next message from source which should be sent to a Pulsar topic |
| */ |
| public void consume(Record<T> record) { |
| try { |
| if (record != null) { |
| queue.put(record); |
| } else { |
| queue.put(nullRecord); |
| } |
| } catch (InterruptedException e) { |
| throw new RuntimeException(e); |
| } |
| } |
| |
| /** |
| * Get length of the queue that records are push onto. |
| * Users can override this method to customize the queue length |
| * @return queue length |
| */ |
| public int getQueueLength() { |
| return DEFAULT_QUEUE_LENGTH; |
| } |
| |
| /** |
| * Allows the source to notify errors asynchronously. |
| * @param ex |
| */ |
| public void notifyError(Exception ex) { |
| consume(new ErrorNotifierRecord(ex)); |
| } |
| } |