org.apache.storm.cassandra.trident.state

Class MapStateFactoryBuilder<T>

java.lang.Object

org.apache.storm.cassandra.trident.state.MapStateFactoryBuilder<T>

public class MapStateFactoryBuilder<T>
extends Object

A helper for building a MapState backed by Cassandra. It internalizes some common implementation choices to simplify usage.

In the simplest use case, a map state can be constructed with:

StateFactory mapState = MapStateFactoryBuilder.opaque() .withTable(“mykeyspace”, “year_month_state”) .withKeys(“year”, “month”) .withJSONBinaryState(“state”) .build();

for a cassandra table with: mykeyspace.year_month_state { year: int, month: int, state: blob }

This will use the storm JSON serializers to convert the state to and from binary format. Other binary serializers can be used with the withBinaryState(String, Serializer) method.

Storing state in explicit fields (e.g. in a field “sum” of type int) is possible by instead calling withStateMapper(StateMapper). For instance, you can use NonTransactionalTupleStateMapper, TransactionalTupleStateMapper or OpaqueTupleStateMapper if your state values are tuples.

Constructor Summary

Constructors

Constructor and Description
MapStateFactoryBuilder()

Method Summary

Modifier and Type	Method and Description
StateFactory	build()
static <U> MapStateFactoryBuilder<U>	nontransactional(Map<String,Object> cassandraConf)
static <U> MapStateFactoryBuilder<OpaqueValue<U>>	opaque(Map<String,Object> cassandraConf)
static <U> MapStateFactoryBuilder<TransactionalValue<U>>	transactional(Map<String,Object> cassandraConf)
MapStateFactoryBuilder<T>	withBinaryState(String stateField, Serializer<T> serializer)
MapStateFactoryBuilder<T>	withCache(int cacheSize)
protected MapStateFactoryBuilder<T>	withCassandraConfig(Map<String,Object> cassandraConf)
MapStateFactoryBuilder<T>	withJSONBinaryState(String stateField)
MapStateFactoryBuilder<T>	withKeys(String... keys)
MapStateFactoryBuilder<T>	withMaxParallelism(Integer maxParallelism)
MapStateFactoryBuilder<T>	withStateMapper(StateMapper<T> stateMapper)
protected MapStateFactoryBuilder<T>	withStateType(StateType stateType)
MapStateFactoryBuilder<T>	withTable(String keyspace, String table)

Methods inherited from class java.lang.Object

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

Constructor Detail

MapStateFactoryBuilder

public MapStateFactoryBuilder()

Method Detail

opaque

public static <U> MapStateFactoryBuilder<OpaqueValue<U>> opaque(Map<String,Object> cassandraConf)

transactional

public static <U> MapStateFactoryBuilder<TransactionalValue<U>> transactional(Map<String,Object> cassandraConf)

nontransactional

public static <U> MapStateFactoryBuilder<U> nontransactional(Map<String,Object> cassandraConf)

withTable

public MapStateFactoryBuilder<T> withTable(String keyspace,
                                           String table)

withKeys

public MapStateFactoryBuilder<T> withKeys(String... keys)

withMaxParallelism

public MapStateFactoryBuilder<T> withMaxParallelism(Integer maxParallelism)

withJSONBinaryState

public MapStateFactoryBuilder<T> withJSONBinaryState(String stateField)

withStateMapper

public MapStateFactoryBuilder<T> withStateMapper(StateMapper<T> stateMapper)

withBinaryState

public MapStateFactoryBuilder<T> withBinaryState(String stateField,
                                                 Serializer<T> serializer)

withStateType

protected MapStateFactoryBuilder<T> withStateType(StateType stateType)

withCassandraConfig

protected MapStateFactoryBuilder<T> withCassandraConfig(Map<String,Object> cassandraConf)

withCache

public MapStateFactoryBuilder<T> withCache(int cacheSize)

build

public StateFactory build()