org.apache.kafka.streams.kstream

Class KStreamBuilder

java.lang.Object

org.apache.kafka.streams.processor.TopologyBuilder

org.apache.kafka.streams.kstream.KStreamBuilder

public class KStreamBuilder
extends TopologyBuilder

KStreamBuilder is a subclass of TopologyBuilder that provides the Kafka Streams DSL for users to specify computational logic and translates the given logic to a org.apache.kafka.streams.processor.internals.ProcessorTopology.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.kafka.streams.processor.TopologyBuilder

TopologyBuilder.TopicsInfo

Constructor Summary

Constructors

Constructor and Description
KStreamBuilder() Create a new KStreamBuilder instance.

Method Summary

Methods

Modifier and Type	Method and Description
<K,V> KStream<K,V>	merge(KStream<K,V>... streams) Create a new instance of KStream by merging the given streams.
String	newName(String prefix) Create a unique processor name used for translation into the processor topology.
<K,V> KStream<K,V>	stream(Pattern topicPattern) Create a KStream instance from the specified Pattern.
<K,V> KStream<K,V>	stream(Serde<K> keySerde, Serde<V> valSerde, Pattern topicPattern) Create a KStream instance from the specified Pattern.
<K,V> KStream<K,V>	stream(Serde<K> keySerde, Serde<V> valSerde, String... topics) Create a KStream instance from the specified topics.
<K,V> KStream<K,V>	stream(String... topics) Create a KStream instance from the specified topics.
<K,V> KTable<K,V>	table(Serde<K> keySerde, Serde<V> valSerde, String topic, String storeName) Create a KTable instance for the specified topic.
<K,V> KTable<K,V>	table(String topic, String storeName) Create a KTable instance for the specified topic.

Methods inherited from class org.apache.kafka.streams.processor.TopologyBuilder

addInternalTopic, addProcessor, addSink, addSink, addSink, addSink, addSource, addSource, addSource, addSource, addStateStore, build, connectProcessorAndStateStores, connectProcessors, connectSourceStoreAndTopic, copartitionGroups, copartitionSources, nodeGroups, setApplicationId, sourceTopicPattern, sourceTopics, stateStoreNameToSourceTopics, topicGroups, updateSubscriptions

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

KStreamBuilder

public KStreamBuilder()

Create a new KStreamBuilder instance.

Method Detail

stream

public <K,V> KStream<K,V> stream(String... topics)

Create a KStream instance from the specified topics. The default deserializers specified in the config are used.

If multiple topics are specified there are nor ordering guaranteed for records from different topics.

Parameters:

topics - the topic names; must contain at least one topic name

Returns:

a KStream for the specified topics

stream

public <K,V> KStream<K,V> stream(Pattern topicPattern)

Create a KStream instance from the specified Pattern. The default deserializers specified in the config are used.

If multiple topics are matched by the specified pattern, the created stream will read data from all of them, and there is no ordering guarantee between records from different topics

Parameters:

topicPattern - the Pattern to match for topic names

Returns:

a KStream for topics matching the regex pattern.

stream

public <K,V> KStream<K,V> stream(Serde<K> keySerde,
                        Serde<V> valSerde,
                        String... topics)

Create a KStream instance from the specified topics.

If multiple topics are specified there are nor ordering guaranteed for records from different topics.

Parameters:

keySerde - key serde used to read this source KStream, if not specified the default serde defined in the configs will be used

valSerde - value serde used to read this source KStream, if not specified the default serde defined in the configs will be used

topics - the topic names; must contain at least one topic name

Returns:

a KStream for the specified topics

stream

public <K,V> KStream<K,V> stream(Serde<K> keySerde,
                        Serde<V> valSerde,
                        Pattern topicPattern)

Create a KStream instance from the specified Pattern.

If multiple topics are matched by the specified pattern, the created stream will read data from all of them, and there is no ordering guarantee between records from different topics.

Parameters:

keySerde - key serde used to read this source KStream, if not specified the default serde defined in the configs will be used

valSerde - value serde used to read this source KStream, if not specified the default serde defined in the configs will be used

topicPattern - the Pattern to match for topic names

Returns:

a KStream for the specified topics

table

public <K,V> KTable<K,V> table(String topic,
                      String storeName)

Create a KTable instance for the specified topic. Record keys of the topic should never by null, otherwise an exception will be thrown at runtime. The default deserializers specified in the config are used. The resulting KTable will be materialized in a local state store with the given store name. However, no new changelog topic is created in this case since the underlying topic acts as one.

Parameters:

topic - the topic name; cannot be null

storeName - the state store name used if this KTable is materialized, can be null if materialization not expected

Returns:

a KTable for the specified topics

table

public <K,V> KTable<K,V> table(Serde<K> keySerde,
                      Serde<V> valSerde,
                      String topic,
                      String storeName)

Create a KTable instance for the specified topic. Record keys of the topic should never by null, otherwise an exception will be thrown at runtime. The resulting KTable will be materialized in a local state store with the given store name. However, no new changelog topic is created in this case since the underlying topic acts as one.

Parameters:

keySerde - key serde used to send key-value pairs, if not specified the default key serde defined in the configuration will be used

valSerde - value serde used to send key-value pairs, if not specified the default value serde defined in the configuration will be used

topic - the topic name; cannot be null

storeName - the state store name used for the materialized KTable

Returns:

a KTable for the specified topics

merge

public <K,V> KStream<K,V> merge(KStream<K,V>... streams)

Create a new instance of KStream by merging the given streams.

There are nor ordering guaranteed for records from different streams.

Parameters:

streams - the instances of KStream to be merged

Returns:

a KStream containing all records of the given streams

newName

public String newName(String prefix)

Create a unique processor name used for translation into the processor topology. This function is only for internal usage.

Parameters:

prefix - processor name prefix

Returns:

a new unique name