KafkaSample (Java Functional Samples)

java.lang.Object
- kafka.KafkaSample

```
public class KafkaSample
extends java.lang.Object
```
Demonstrate integrating with the Apache Kafka messaging system http://kafka.apache.org.
Connectors are used to create a bridge between topology streams and a Kafka cluster:
- KafkaConsumer - subscribe to Kafka topics and create streams of messages.
- KafkaProducer - publish streams of messages to Kafka topics.
The sample publishes some messages to a Kafka topic. It also subscribes to the topic and reports the messages received. The messages received may include messages from prior runs of the sample.
The sample requires a running Kafka cluster with the following characteristics:
- the kafka topic (@code kafkaSampleTopic} has been created. e.g.
  ${KAFKA_HOME}/bin/kafka-topics.sh --create --zookeeper localhost:2181 --replication-factor 1 --partitions 1 --topic kafkaSampleTopic
- the Kafka cluster's zookeeper connection is localhost:2181
- the Kafka cluster's brokers addresses is localhost:9092
Required IBM Streams environment variables:
- STREAMS_INSTALL - the Streams installation directory
- STREAMS_DOMAIN_ID - the Streams domain to use for context DISTRIBUTED
- STREAMS_INSTANCE_ID - the Streams instance to use for context DISTRIBUTED
See the Apache Kafka link above for information about setting up a Kafka cluster and creating a topic.
This may be executed from the samples/java/functional directory as:
- ant run.kafka.distributed - Using Apache Ant, this will run in distributed mode.
- ant run.kafka - Using Apache Ant, this will run in standalone mode.
- java -cp functionalsamples.jar:../../../com.ibm.streamsx.topology/lib/com.ibm.streamsx.topology.jar:$STREAMS_INSTALL/lib/com.ibm.streams.operator.samples.jar kafka.KafkaSample CONTEXT_TYPE - Run directly from the command line.
- An application execution within your IDE once you set the class path to include the correct jars.

Constructor Summary

Constructors
Constructor and Description

KafkaSample()

Constructors
Constructor and Description
`KafkaSample()`

Method Summary

All Methods Static Methods Instance Methods Concrete Methods
Modifier and Type	Method and Description
`static void`	`main(java.lang.String[] args)`
`void`	`publishSubscribe(java.lang.String contextType)` Publish some messages to a topic, scribe to the topic and report received messages.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Constructor Detail
  - KafkaSample
```
public KafkaSample()
```
- Method Detail
  - main
```
public static void main(java.lang.String[] args)
                 throws java.lang.Exception
```
    Throws:
    
    java.lang.Exception
  - publishSubscribe
```
public void publishSubscribe(java.lang.String contextType)
                      throws java.lang.Exception
```
    Publish some messages to a topic, scribe to the topic and report received messages.
    
    Parameters:
    
    contextType - string value of a StreamsContext.Type
    
    Throws:
    
    java.lang.Exception

Methods inherited from class java.lang.Object

KafkaSample

main

publishSubscribe