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

Class CollectionSerde<E>

java.lang.Object

org.springframework.cloud.stream.binder.kafka.streams.serde.CollectionSerde<E>

Type Parameters:

E - type of the underlying object that the collection holds

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.kafka.common.serialization.Serde<Collection<E>>

public class CollectionSerde<E>
extends Object
implements org.apache.kafka.common.serialization.Serde<Collection<E>>

A convenient Serde for Collection implementations. Whenever a Kafka Stream application needs to collect data into a container object like Collection, then this Serde class can be used as a convenience for serialization needs. Some examples of where using this may handy is when the application needs to do aggregation or reduction operations where it needs to simply hold an Iterable type. By default, this Serde will use JsonSerde for serializing the inner objects. This can be changed by providing an explicit Serde during creation of this object. Here is an example of a possible use case:

                .aggregate(ArrayList::new,
                                        (k, v, aggregates) -> {
                                                        aggregates.add(v);
                                                        return aggregates;
                                                },
                                        Materialized.<String, Collection<Foo>, WindowStore<Bytes, byte[]>>as(
                                                "foo-store")
                                                .withKeySerde(Serdes.String())
                                                .withValueSerde(new CollectionSerde<>(Foo.class, ArrayList.class)))
  * 

Supported Collection types by this Serde are - ArrayList, LinkedList, PriorityQueue and HashSet. Deserializer will throw an exception if any other Collection types are used.

Since:

3.0.0

Author:

Soby Chacko

Constructor Summary

Constructors

Constructor and Description
CollectionSerde(Class<?> targetTypeForJsonSerde, Class<?> collectionsClass) Constructor to delegate serialization operations for the inner objects to JsonSerde.
CollectionSerde(org.apache.kafka.common.serialization.Serde<E> serde, Class<?> collectionsClass) Constructor to use when the application wants to specify the type of the Serde used for the inner object.

Method Summary

Modifier and Type	Method and Description
void	close()
void	configure(Map<String,?> configs, boolean isKey)
org.apache.kafka.common.serialization.Deserializer<Collection<E>>	deserializer()
org.apache.kafka.common.serialization.Serializer<Collection<E>>	serializer()

Methods inherited from class java.lang.Object

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

Constructor Detail

CollectionSerde

public CollectionSerde(org.apache.kafka.common.serialization.Serde<E> serde,
                       Class<?> collectionsClass)

Constructor to use when the application wants to specify the type of the Serde used for the inner object.

Parameters:

serde - specify an explicit Serde

collectionsClass - type of the Collection class

CollectionSerde

public CollectionSerde(Class<?> targetTypeForJsonSerde,
                       Class<?> collectionsClass)

Constructor to delegate serialization operations for the inner objects to JsonSerde.

Parameters:

targetTypeForJsonSerde - target type used by the JsonSerde

collectionsClass - type of the Collection class

Method Detail

serializer

public org.apache.kafka.common.serialization.Serializer<Collection<E>> serializer()

Specified by:

serializer in interface org.apache.kafka.common.serialization.Serde<Collection<E>>

deserializer

public org.apache.kafka.common.serialization.Deserializer<Collection<E>> deserializer()

Specified by:

deserializer in interface org.apache.kafka.common.serialization.Serde<Collection<E>>

configure

public void configure(Map<String,?> configs,
                      boolean isKey)

Specified by:

configure in interface org.apache.kafka.common.serialization.Serde<Collection<E>>

close

public void close()

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable

Specified by:

close in interface org.apache.kafka.common.serialization.Serde<Collection<E>>