trunk/examples/src/main/java/kafka/examples/SimpleConsumerDemo.java

/**
 * 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 kafka.examples;


import java.util.ArrayList;
import java.util.List;
import kafka.api.FetchRequest;
import kafka.javaapi.MultiFetchResponse;
import kafka.javaapi.consumer.SimpleConsumer;
import kafka.javaapi.message.ByteBufferMessageSet;
import kafka.message.MessageAndOffset;


public class SimpleConsumerDemo
{
  private static void printMessages(ByteBufferMessageSet messageSet)
  {
    for (MessageAndOffset messageAndOffset : messageSet) {
      System.out.println(ExampleUtils.getMessage(messageAndOffset.message()));
    }
  }

  private static void generateData()
  {
    Producer producer2 = new Producer(KafkaProperties.topic2);
    producer2.start();
    Producer producer3 = new Producer(KafkaProperties.topic3);
    producer3.start();
    try
    {
      Thread.sleep(1000);
    }
    catch (InterruptedException e)
    {
      e.printStackTrace();
    }
  }
  
  public static void main(String[] args)
  {
    
    generateData();
    SimpleConsumer simpleConsumer = new SimpleConsumer(KafkaProperties.kafkaServerURL,
                                                       KafkaProperties.kafkaServerPort,
                                                       KafkaProperties.connectionTimeOut,
                                                       KafkaProperties.kafkaProducerBufferSize);

    System.out.println("Testing single fetch");
    FetchRequest req = new FetchRequest(KafkaProperties.topic2, 0, 0L, 100);
    ByteBufferMessageSet messageSet = simpleConsumer.fetch(req);
    printMessages(messageSet);

    System.out.println("Testing single multi-fetch");
    req = new FetchRequest(KafkaProperties.topic2, 0, 0L, 100);
    List<FetchRequest> list = new ArrayList<FetchRequest>();
    list.add(req);
    req = new FetchRequest(KafkaProperties.topic3, 0, 0L, 100);
    list.add(req);
    MultiFetchResponse response = simpleConsumer.multifetch(list);
    int fetchReq = 0;
    for (ByteBufferMessageSet resMessageSet : response )
    {
      System.out.println("Response from fetch request no: " + ++fetchReq);
      printMessages(resMessageSet);
    }
  }

}