com.lightbend.lagom.javadsl.persistence

Class AggregateEventTag$

Object

com.lightbend.lagom.javadsl.persistence.AggregateEventTag$

public class AggregateEventTag$
extends Object

Field Summary

Fields

Modifier and Type	Field and Description
static AggregateEventTag$	MODULE$ Static reference to the singleton instance of this Scala object.

Constructor Summary

Constructors

Constructor and Description
AggregateEventTag$()

Method Summary

Modifier and Type	Method and Description
<Event extends AggregateEvent<Event>> AggregateEventTag<Event>	of(Class<Event> eventType) Convenience factory method of AggregateEventTag that uses the class name of the event type as tag.
<Event extends AggregateEvent<Event>> AggregateEventTag<Event>	of(Class<Event> eventType, String tag) Factory method of AggregateEventTag.
int	selectShard(int numShards, String entityId) Select a shard given the number of shards and the ID of the entity.
<Event extends AggregateEvent<Event>> AggregateEventShards<Event>	sharded(Class<Event> eventType, int numShards) Create an aggregate event shards tagger.
<Event extends AggregateEvent<Event>> AggregateEventShards<Event>	sharded(Class<Event> eventType, String baseTagName, int numShards) Create a sharded aggregate event tag.
String	shardTag(String baseTagName, int shardNo) Generate a shard tag according to the base tag name and the shard number.

Methods inherited from class Object

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

Field Detail

MODULE$

public static final AggregateEventTag$ MODULE$

Static reference to the singleton instance of this Scala object.

Constructor Detail

AggregateEventTag$

public AggregateEventTag$()

Method Detail

of

public <Event extends AggregateEvent<Event>> AggregateEventTag<Event> of(Class<Event> eventType)

Convenience factory method of AggregateEventTag that uses the class name of the event type as tag. Note that it is needed to retain the original tag when the class name is changed because the tag is part of the store event data.

of

public <Event extends AggregateEvent<Event>> AggregateEventTag<Event> of(Class<Event> eventType,
                                                                         String tag)

Factory method of AggregateEventTag.

sharded

public <Event extends AggregateEvent<Event>> AggregateEventShards<Event> sharded(Class<Event> eventType,
                                                                                 int numShards)

Create an aggregate event shards tagger.

This is a convenience function that uses the name of the class as the tag name. Note that if the class name changes, the tag name must be retained, and so this method will no longer be suitable for use.

Events that return this will be tagged with a tag that is based on a hash of the events persistence ID, modulo the number of shards.

The numShards should be selected up front, and shouldn't change. If it does change, events for the same entity will be produced by different event streams and handled by different shards in the read side processor, leading to out of order event handling.

Parameters:

eventType - The type of the event.

numShards - The number of shards.

Returns:

The aggregate event shards tagger.

sharded

public <Event extends AggregateEvent<Event>> AggregateEventShards<Event> sharded(Class<Event> eventType,
                                                                                 String baseTagName,
                                                                                 int numShards)

Create a sharded aggregate event tag.

Events that return this will be tagged with a tag that is based on a hash of the events persistence ID, modulo the number of shards.

The numShards should be selected up front, and shouldn't change. If it does change, events for the same entity will be produced by different event streams and handled by different shards in the read side processor, leading to out of order event handling.

Parameters:

eventType - The type of the event.

baseTagName - The base name for the tag, this will be combined with the shard number to form the tag name.

numShards - The number of shards.

Returns:

The aggregate event shards tagger.

selectShard

public int selectShard(int numShards,
                       String entityId)

Select a shard given the number of shards and the ID of the entity.

Parameters:

numShards - The number of shards.

entityId - The ID of the entity.

Returns:

The selected shard number.

shardTag

public String shardTag(String baseTagName,
                       int shardNo)

Generate a shard tag according to the base tag name and the shard number.

Parameters:

baseTagName - The base tag name.

shardNo - The shard number.

Returns:

The name of the shard tag.