Lattice

The VLINGO XOOM platform toolset providing compute grid, actor caching, object spaces, cross-node cluster messaging, publish-subscribe, CQRS, and Event Sourcing support.

Feature Overview

The XOOM Lattice component provides tooling for reactive Domain-Driven Design projects that are highly concurrent. The tools of the component include compute grid, actor caching, spaces, cross-node cluster messaging, publish-subscribe, CQRS, and Event Sourcing support.

Feature	Description
CQRS	Understanding the Command-Query Responsibility Segregation pattern.
Object, Stateful, and Sourced Entities with CQRS	Supports three styles of persistence, including Object, Stateful, and Sourced. Command-Query Responsibility Segregation uses two models per Bounded Context (application or service), the Command Model and the Query Model, otherwise known as the Read Model and the Write Model, respectively.
Grid	Provides an API for distributed computations and data processing across multiple nodes in a cluster. Supports distributed parallel processing by sending computational execution requests to actors on any node in a cluster with the potential to receive results in return.
Exchange	Provides an abstraction over Publish-Subscribe messaging exchanges or topics. This is a means to publish messages to exchanges/topics inside or outside your current application/service, and to subscribe to such messages. Provides translators from internal to external message types, and from external to internal message types.
Processes	Long-running processes that manage complex, coarse-grained, business transactions, must be managed through every step until completion. These tools assist in managing such processes whether by means of object persistence, stateful command models, or sourced with commands.
Projections	How to project state, Domain Events, and other Source types into a CQRS Query Model.
Routers	Use message-driven command routing to handlers that are responsible for modifying the domain model, which may be segregated as a Command Model.

Types

The following types are defined in the XOOM Lattice component and commonly used with domain-driven designed services.

Type	Descriptio
DomainEvent	A abstract type used to model a record of fact about an important business occurrence in the domain model
IdentifiedDomainEvent	A abstract type used to model a record of fact about an important business occurrence in the domain model and that has an identity associated with it, which can be used for correlation
EventSourced	An abstract type used to create an Event Sourced entity that is backed by a persistent Journal
Command	An abstract type used to model a record of an imperative directive to carry out a business operation
CommandSourced	An abstract type used to create an Command Sourced entity
ObjectEntity	An abstract type used to model an entity that is backed by object-relational persistence
StatefulEntity	An abstract type used to model an entity that is backed by Key-Value persistence
Process	An interface implemented by a component that orchestrates the steps necessary to complete a composite task
Projection	An interface implemented by a component that serves to project Command Model state onto the Query Model
Projectable	An interface used to abstract the Command Model data projected onto the Query Model
Exchange	An abstraction over Publish-Subscribe messaging exchanges and topics
CommandRouter	A means of asynchronous message-driven command routing to handlers that are responsible for modifying the domain model

These types are discussed in detail throughout the subsections of this chapter.