ReadSideProcessor

A read side processor.

Read side processors consume events produced by com.lightbend.lagom.scaladsl.persistence.PersistentEntity instances, and update some read side data store that is optimized for queries.

The events they consume must be tagged, and a read side is able to consume events of one or more tags. Events are usually tagged according to some supertype of event, for example, events may be tagged as Order events. They may also be tagged according to a hash of the ID of the entity associated with the event - this allows read side event handling to be sharded across many nodes. Tagging is done using com.lightbend.lagom.scaladsl.persistence.AggregateEventTag.

Read side processors are responsible for tracking what events they have already seen. This is done using offsets, which are sequential values associated with each event. Note that end users typically will not need to handle offsets themselves, this will be provided by Lagom support specific to the read side datastore, and end users can just focus on handling the events themselves.

Source: ReadSideProcessor.scala

Linear Supertypes

AnyRef, Any

Instance Constructors

new ReadSideProcessor()

Abstract Value Members

abstract def aggregateTags: Set[AggregateEventTag[Event]]

The tags to aggregate.
The tags to aggregate.
This must return at least one tag to aggregate. Read side processors will be sharded over the cluster by these tags, so if events are tagged by a shard key, the read side processing load can be distributed across the cluster.
returns
The tags to aggregate.
abstract def buildHandler(): ReadSideHandler[Event]

Return a ReadSideProcessor#ReadSideHandler for the given offset type.
Return a ReadSideProcessor#ReadSideHandler for the given offset type.
returns
The offset processor.

Concrete Value Members

final def !=(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def ##(): Int

Definition Classes
AnyRef → Any
def +(other: String): String

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to any2stringadd[ReadSideProcessor[Event]] performed by method any2stringadd in scala.Predef.
Definition Classes
any2stringadd
def ->[B](y: B): (ReadSideProcessor[Event], B)

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to ArrowAssoc[ReadSideProcessor[Event]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc
Annotations
@inline()
final def ==(arg0: Any): Boolean

Definition Classes
AnyRef → Any
final def asInstanceOf[T0]: T0

Definition Classes
Any
def clone(): AnyRef

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( ... )
def ensuring(cond: (ReadSideProcessor[Event]) ⇒ Boolean, msg: ⇒ Any): ReadSideProcessor[Event]

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to Ensuring[ReadSideProcessor[Event]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: (ReadSideProcessor[Event]) ⇒ Boolean): ReadSideProcessor[Event]

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to Ensuring[ReadSideProcessor[Event]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean, msg: ⇒ Any): ReadSideProcessor[Event]

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to Ensuring[ReadSideProcessor[Event]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
def ensuring(cond: Boolean): ReadSideProcessor[Event]

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to Ensuring[ReadSideProcessor[Event]] performed by method Ensuring in scala.Predef.
Definition Classes
Ensuring
final def eq(arg0: AnyRef): Boolean

Definition Classes
AnyRef
def equals(arg0: Any): Boolean

Definition Classes
AnyRef → Any
def finalize(): Unit

Attributes
protected[java.lang]
Definition Classes
AnyRef
Annotations
@throws( classOf[java.lang.Throwable] )
def formatted(fmtstr: String): String

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to StringFormat[ReadSideProcessor[Event]] performed by method StringFormat in scala.Predef.
Definition Classes
StringFormat
Annotations
@inline()
final def getClass(): Class[_]

Definition Classes
AnyRef → Any
def hashCode(): Int

Definition Classes
AnyRef → Any
final def isInstanceOf[T0]: Boolean

Definition Classes
Any
final def ne(arg0: AnyRef): Boolean

Definition Classes
AnyRef
final def notify(): Unit

Definition Classes
AnyRef
final def notifyAll(): Unit

Definition Classes
AnyRef
def readSideName: String

The name of this read side.
The name of this read side.
This name should be unique among the read sides and entity types of the service. By default it is using the short class name of the concrete ReadSideProcessor class. Subclasses may override to define other type names. It is wise to override and retain the original name when the class name is changed because this name is used to identify read sides throughout the cluster.
final def synchronized[T0](arg0: ⇒ T0): T0

Definition Classes
AnyRef
def toString(): String

Definition Classes
AnyRef → Any
final def wait(): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long, arg1: Int): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
final def wait(arg0: Long): Unit

Definition Classes
AnyRef
Annotations
@throws( ... )
def →[B](y: B): (ReadSideProcessor[Event], B)

Implicit information
This member is added by an implicit conversion from ReadSideProcessor[Event] to ArrowAssoc[ReadSideProcessor[Event]] performed by method ArrowAssoc in scala.Predef.
Definition Classes
ArrowAssoc

Related Docs: object ReadSideProcessor | package persistence

abstract class ReadSideProcessor[Event <: AggregateEvent[Event]] extends AnyRef

Instance Constructors

new ReadSideProcessor()

Abstract Value Members

abstract def aggregateTags: Set[AggregateEventTag[Event]]

abstract def buildHandler(): ReadSideHandler[Event]

Concrete Value Members

final def !=(arg0: Any): Boolean

final def ##(): Int

def +(other: String): String

def ->[B](y: B): (ReadSideProcessor[Event], B)

final def ==(arg0: Any): Boolean

final def asInstanceOf[T0]: T0

def clone(): AnyRef

def ensuring(cond: (ReadSideProcessor[Event]) ⇒ Boolean, msg: ⇒ Any): ReadSideProcessor[Event]

def ensuring(cond: (ReadSideProcessor[Event]) ⇒ Boolean): ReadSideProcessor[Event]

def ensuring(cond: Boolean, msg: ⇒ Any): ReadSideProcessor[Event]

def ensuring(cond: Boolean): ReadSideProcessor[Event]

final def eq(arg0: AnyRef): Boolean

def equals(arg0: Any): Boolean

def finalize(): Unit

def formatted(fmtstr: String): String

final def getClass(): Class[_]

def hashCode(): Int

final def isInstanceOf[T0]: Boolean

final def ne(arg0: AnyRef): Boolean

final def notify(): Unit

final def notifyAll(): Unit

def readSideName: String

final def synchronized[T0](arg0: ⇒ T0): T0

def toString(): String

final def wait(): Unit

final def wait(arg0: Long, arg1: Int): Unit

final def wait(arg0: Long): Unit

def →[B](y: B): (ReadSideProcessor[Event], B)

Inherited from AnyRef

Inherited from Any

Inherited by implicit conversion any2stringadd from ReadSideProcessor[Event] to any2stringadd[ReadSideProcessor[Event]]

Inherited by implicit conversion StringFormat from ReadSideProcessor[Event] to StringFormat[ReadSideProcessor[Event]]

Inherited by implicit conversion Ensuring from ReadSideProcessor[Event] to Ensuring[ReadSideProcessor[Event]]

Inherited by implicit conversion ArrowAssoc from ReadSideProcessor[Event] to ArrowAssoc[ReadSideProcessor[Event]]

Ungrouped