MINOR: Improve topic management instructions for Kafka Streams examples

Author: Michael G. Noll <[email protected]>

Reviewers: Matthias J. Sax <[email protected]>, Eno Thereska <[email protected]>, Ismael Juma <[email protected]>

Closes apache#2812 from miguno/trunk-streams-examples-docs

streams/examples/src/main/java/org/apache/kafka/streams/examples/pageview/PageViewTypedDemo.java

@@ -41,12 +41,13 @@
  * using specific data types (here: JSON POJO; but can also be Avro specific bindings, etc.) for serdes
  * in Kafka Streams.
  *
- * In this example, we join a stream of pageviews (aka clickstreams) that reads from  a topic named "streams-pageview-input"
+ * In this example, we join a stream of pageviews (aka clickstreams) that reads from a topic named "streams-pageview-input"
  * with a user profile table that reads from a topic named "streams-userprofile-input", where the data format
  * is JSON string representing a record in the stream or table, to compute the number of pageviews per user region.
  *
- * Before running this example you must create the source topic (e.g. via bin/kafka-topics.sh --create ...)
- * and write some data to it (e.g. via bin-kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
+ * Before running this example you must create the input topics and the output topic (e.g. via
+ * bin/kafka-topics.sh --create ...), and write some data to the input topics (e.g. via
+ * bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
  */
 public class PageViewTypedDemo {
 

streams/examples/src/main/java/org/apache/kafka/streams/examples/pageview/PageViewUntypedDemo.java

@@ -49,8 +49,9 @@
  * with a user profile table that reads from a topic named "streams-userprofile-input", where the data format
  * is JSON string representing a record in the stream or table, to compute the number of pageviews per user region.
  *
- * Before running this example you must create the source topic (e.g. via bin/kafka-topics.sh --create ...)
- * and write some data to it (e.g. via bin-kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
+ * Before running this example you must create the input topics and the output topic (e.g. via
+ * bin/kafka-topics.sh --create ...), and write some data to the input topics (e.g. via
+ * bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
  */
 public class PageViewUntypedDemo {
 

streams/examples/src/main/java/org/apache/kafka/streams/examples/pipe/PipeDemo.java

@@ -31,8 +31,9 @@
  * In this example, we implement a simple "pipe" program that reads from a source topic "streams-file-input"
  * and writes the data as-is (i.e. unmodified) into a sink topic "streams-pipe-output".
  *
- * Before running this example you must create the source topic (e.g. via bin/kafka-topics.sh --create ...)
- * and write some data to it (e.g. via bin-kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
+ * Before running this example you must create the input topic and the output topic (e.g. via
+ * bin/kafka-topics.sh --create ...), and write some data to the input topic (e.g. via
+ * bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
  */
 public class PipeDemo {
 

streams/examples/src/main/java/org/apache/kafka/streams/examples/wordcount/WordCountDemo.java

@@ -39,8 +39,9 @@
  * represent lines of text; and the histogram output is written to topic "streams-wordcount-output" where each record
  * is an updated count of a single word.
  *
- * Before running this example you must create the source topic (e.g. via bin/kafka-topics.sh --create ...)
- * and write some data to it (e.g. via bin-kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
+ * Before running this example you must create the input topic and the output topic (e.g. via
+ * bin/kafka-topics.sh --create ...), and write some data to the input topic (e.g. via
+ * bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
  */
 public class WordCountDemo {
 

streams/examples/src/main/java/org/apache/kafka/streams/examples/wordcount/WordCountProcessorDemo.java

@@ -40,8 +40,9 @@
  * represent lines of text; and the histogram output is written to topic "streams-wordcount-processor-output" where each record
  * is an updated count of a single word.
  *
- * Before running this example you must create the source topic (e.g. via bin/kafka-topics.sh --create ...)
- * and write some data to it (e.g. via bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
+ * Before running this example you must create the input topic and the output topic (e.g. via
+ * bin/kafka-topics.sh --create ...), and write some data to the input topic (e.g. via
+ * bin/kafka-console-producer.sh). Otherwise you won't see any data arriving in the output topic.
  */
 public class WordCountProcessorDemo {