| /** |
| * 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 com.datatorrent.contrib.kafka; |
| |
| import java.nio.ByteBuffer; |
| import java.nio.charset.Charset; |
| import java.nio.charset.CharsetDecoder; |
| import java.util.Iterator; |
| |
| import kafka.api.FetchRequest; |
| import kafka.api.FetchRequestBuilder; |
| import kafka.javaapi.consumer.SimpleConsumer; |
| import kafka.javaapi.message.ByteBufferMessageSet; |
| import kafka.message.MessageAndOffset; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| /** |
| * |
| */ |
| public class KafkaSimpleConsumer implements Runnable |
| { |
| private static final Logger logger = LoggerFactory.getLogger(KafkaSimpleConsumer.class); |
| private SimpleConsumer consumer; |
| private Charset charset = Charset.forName("UTF-8"); |
| private CharsetDecoder decoder = charset.newDecoder(); |
| private int receiveCount = 0; |
| private boolean isAlive = true; |
| |
| public KafkaSimpleConsumer() |
| { |
| // create a consumer to connect to the kafka kserver running on localhost, port 2182, socket timeout of 10 secs, socket receive buffer of ~1MB |
| consumer = new SimpleConsumer("localhost", 2182, 10000, 1024000, "default_client"); |
| } |
| |
| public int getReceiveCount() |
| { |
| return receiveCount; |
| } |
| |
| public void setReceiveCount(int receiveCount) |
| { |
| this.receiveCount = receiveCount; |
| } |
| |
| public void setIsAlive(boolean isAlive) |
| { |
| this.isAlive = isAlive; |
| } |
| |
| public String byteBufferToString(ByteBuffer buffer) |
| { |
| String data = ""; |
| try { |
| int old_position = buffer.position(); |
| data = decoder.decode(buffer).toString(); |
| // reset buffer's position to its original so it is not altered: |
| buffer.position(old_position); |
| } |
| catch (Exception e) { |
| return data; |
| } |
| return data; |
| } |
| |
| @Override |
| public void run() |
| { |
| long offset = 0; |
| while (isAlive) { |
| // create a fetch request for topic “topic1”, partition 0, current offset, and fetch size of 1MB |
| FetchRequest fetchRequest = new FetchRequestBuilder().clientId("default_client").addFetch("topic1", 1, offset, 1000000).build(); |
| |
| // FetchRequest fetchRequest = new FetchRequest("topic1", 0, offset, 1000000); |
| |
| // get the message set from the consumer and print them out |
| ByteBufferMessageSet messages = consumer.fetch(fetchRequest).messageSet("topic1", 1); |
| Iterator<MessageAndOffset> itr = messages.iterator(); |
| |
| while (itr.hasNext() && isAlive) { |
| MessageAndOffset msg = itr.next(); |
| // advance the offset after consuming each message |
| offset = msg.offset(); |
| logger.debug("consumed: {} offset: {}", byteBufferToString(msg.message().payload()).toString(), offset); |
| receiveCount++; |
| } |
| } |
| } |
| |
| public void close() |
| { |
| consumer.close(); |
| } |
| } |