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MINOR: update streams quickstart for KIP-182 

Author: Damian Guy <damian.guy@gmail.com>

Reviewers: Michael G. Noll <michael@confluent.io>, Bill Bejeck <bill@confluent.io>, Matthias J. Sax <matthias@confluent.io>, Guozhang Wang <wangguoz@gmail.com>

Closes #3984 from dguy/quickstart-update
This commit is contained in:
Damian Guy 2017-10-04 12:19:40 -07:00 committed by Guozhang Wang
parent ac7695c32a
commit 93b71e7dee
3 changed files with 28 additions and 17 deletions
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7
docs/streams/quickstart.html
View File

@ -44,7 +44,8 @@ final Serde&lt;Long&gt; longSerde = Serdes.Long();
// Construct a `KStream` from the input topic "streams-plaintext-input", where message values
// represent lines of text (for the sake of this example, we ignore whatever may be stored
// in the message keys).
KStream&lt;String, String&gt; textLines = builder.stream(stringSerde, stringSerde, "streams-plaintext-input");
KStream&lt;String, String&gt; textLines = builder.stream("streams-plaintext-input",
Consumed.with(stringSerde, stringSerde);
KTable&lt;String, Long&gt; wordCounts = textLines
// Split each text line, by whitespace, into words.
@ -54,10 +55,10 @@ KTable&lt;String, Long&gt; wordCounts = textLines
.groupBy((key, value) -> value)
// Count the occurrences of each word (message key).
.count("Counts")
.count()
// Store the running counts as a changelog stream to the output topic.
wordCounts.to(stringSerde, longSerde, "streams-wordcount-output");
wordCounts.toStream().to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long()));
</pre>
<p>

20
docs/streams/tutorial.html
View File

@ -485,12 +485,14 @@
return value;
}
})
.count("Counts");
// Materialize the result into a KeyValueStore named "counts-store".
// The Materialized store is always of type &lt;Bytes, byte[]&gt; as this is the format of the inner most store.
.count(Materialized.&lt;String, Long, KeyValueStore&lt;Bytes, byte[]&gt;&gt; as("counts-store"));
</pre>
<p>
Note that the <code>count</code> operator has a <code>String</code> typed parameter <code>Counts</code>,
which stores the running counts that keep being updated as more records are piped and processed from the source Kafka topic.
Note that the <code>count</code> operator has a <code>Materialized</code> parameter that specifies that the
running count should be stored in a state store named <code>counts-store</code>.
This <code>Counts</code> store can be queried in real-time, with details described in the <a href="/{{version}}/documentation/streams/developer-guide#streams_interactive_queries">Developer Manual</a>.
</p>
@ -502,7 +504,7 @@
</p>
<pre class="brush: java;">
counts.to(Serdes.String(), Serdes.Long(), "streams-wordcount-output");
counts.toStream().to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long());
</pre>
<p>
@ -516,8 +518,9 @@
KStream&lt;String, String&gt; source = builder.stream("streams-plaintext-input");
source.flatMapValues(value -> Arrays.asList(value.toLowerCase(Locale.getDefault()).split("\\W+")))
.groupBy((key, value) -> value)
.count("Counts")
.to(Serdes.String(), Serdes.Long(), "streams-wordcount-output");
.count(Materialized.&lt;String, Long, KeyValueStore&lt;Bytes, byte[]&gt;&gt;as("counts-store"))
.toStream()
.to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long());
</pre>
<p>
@ -589,8 +592,9 @@
KStream&lt;String, String&gt; source = builder.stream("streams-plaintext-input");
source.flatMapValues(value -> Arrays.asList(value.toLowerCase(Locale.getDefault()).split("\\W+")))
.groupBy((key, value) -> value)
.count("Counts")
.to(Serdes.String(), Serdes.Long(), "streams-wordcount-output");
.count(Materialized.&lt;String, Long, KeyValueStore&lt;Bytes, byte[]&gt;&gt;as("counts-store"))
.toStream()
.to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long());
final Topology topology = builder.build();
final KafkaStreams streams = new KafkaStreams(topology, props);

18
streams/quickstart/java/src/main/resources/archetype-resources/src/main/java/WordCount.java
View File

@ -17,12 +17,16 @@
package ${package};
import org.apache.kafka.common.serialization.Serdes;
import org.apache.kafka.common.utils.Bytes;
import org.apache.kafka.streams.KafkaStreams;
import org.apache.kafka.streams.StreamsBuilder;
import org.apache.kafka.streams.StreamsConfig;
import org.apache.kafka.streams.Topology;
import org.apache.kafka.streams.kstream.KeyValueMapper;
import org.apache.kafka.streams.kstream.Materialized;
import org.apache.kafka.streams.kstream.Produced;
import org.apache.kafka.streams.kstream.ValueMapper;
import org.apache.kafka.streams.state.KeyValueStore;
import java.util.Arrays;
import java.util.Locale;
@ -59,17 +63,19 @@ public class WordCount {
return value;
}
})
.count("Counts")
.to(Serdes.String(), Serdes.Long(), "streams-wordcount-output");
.count(Materialized.<String, Long, KeyValueStore<Bytes, byte[]>>as("counts-store"))
.toStream()
.to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long()));
/* ------- use the code below for Java 8 and uncomment the above ----
/* ------- use the code below for Java 8 and comment the above ----
builder.stream("streams-plaintext-input")
builder.<String, String>stream("streams-plaintext-input")
.flatMapValues(value -> Arrays.asList(value.toLowerCase(Locale.getDefault()).split("\\W+")))
.groupBy((key, value) -> value)
.count("Counts")
.to(Serdes.String(), Serdes.Long(), "streams-wordcount-output");
.count(Materialized.<String, Long, KeyValueStore<Bytes, byte[]>>as("counts-store"))
.toStream()
.to("streams-wordcount-output", Produced.with(Serdes.String(), Serdes.Long()));
----------------------------------------------------------------- */