org.springframework.cloud.stream.binder.kafka.streams

Class InteractiveQueryService

java.lang.Object

org.springframework.cloud.stream.binder.kafka.streams.InteractiveQueryService

public class InteractiveQueryService
extends Object

Services pertinent to the interactive query capabilities of Kafka Streams. This class provides services such as querying for a particular store, which instance is hosting a particular store etc. This is part of the public API of the kafka streams binder and the users can inject this service in their applications to make use of it.

Since:

2.1.0

Author:

Soby Chacko, Renwei Han

Constructor Summary

Constructors

Constructor and Description
InteractiveQueryService(org.springframework.cloud.stream.binder.kafka.streams.KafkaStreamsRegistry kafkaStreamsRegistry, KafkaStreamsBinderConfigurationProperties binderConfigurationProperties) Constructor for InteractiveQueryService.

Method Summary

Modifier and Type	Method and Description
org.apache.kafka.streams.state.HostInfo	getCurrentHostInfo() Gets the current HostInfo that the calling kafka streams application is running on.
<K> org.apache.kafka.streams.state.HostInfo	getHostInfo(String store, K key, org.apache.kafka.common.serialization.Serializer<K> serializer) Gets the HostInfo where the provided store and key are hosted on.
<T> T	getQueryableStore(String storeName, org.apache.kafka.streams.state.QueryableStoreType<T> storeType) Retrieve and return a queryable store by name created in the application.

Methods inherited from class java.lang.Object

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

Constructor Detail

InteractiveQueryService

public InteractiveQueryService(org.springframework.cloud.stream.binder.kafka.streams.KafkaStreamsRegistry kafkaStreamsRegistry,
                               KafkaStreamsBinderConfigurationProperties binderConfigurationProperties)

Constructor for InteractiveQueryService.

Parameters:

kafkaStreamsRegistry - holding KafkaStreamsRegistry

binderConfigurationProperties - kafka Streams binder configuration properties

Method Detail

getQueryableStore

public <T> T getQueryableStore(String storeName,
                               org.apache.kafka.streams.state.QueryableStoreType<T> storeType)

Retrieve and return a queryable store by name created in the application.

Type Parameters:

T - generic queryable store

Parameters:

storeName - name of the queryable store

storeType - type of the queryable store

Returns:

queryable store.

getCurrentHostInfo

public org.apache.kafka.streams.state.HostInfo getCurrentHostInfo()

Gets the current HostInfo that the calling kafka streams application is running on. Note that the end user applications must provide `applicaiton.server` as a configuration property when calling this method. If this is not available, then null is returned.

Returns:

the current HostInfo

getHostInfo

public <K> org.apache.kafka.streams.state.HostInfo getHostInfo(String store,
                                                               K key,
                                                               org.apache.kafka.common.serialization.Serializer<K> serializer)

Gets the HostInfo where the provided store and key are hosted on. This may not be the current host that is running the application. Kafka Streams will look through all the consumer instances under the same application id and retrieves the proper host. Note that the end user applications must provide `applicaiton.server` as a configuration property for all the application instances when calling this method. If this is not available, then null maybe returned.

Type Parameters:

K - generic type for key

Parameters:

store - store name

key - key to look for

serializer - Serializer for the key

Returns:

the HostInfo where the key for the provided store is hosted currently