Apache Causeway Documentation

Summary of changes in version 2.0.0-M7:

Key Highlights

• Encapsulation: Support for non-public visibility of members via ENCAPSULATION_ENABLED policy.
• Value Types: Reworked treatment of value types and refactored implementation in the Wicket viewer.
• Localization: Support for UserLocale (language, number, and time formats) via UserMemento.
• Type Mapping: Improved handling of @LogicalTypeName for superclasses.
• Dependencies: Updated to DataNucleus 6.

Notable New Features

• Declarative Interaction Context Specification for testing.
• Per-user Locale support.
• Direct export of Collection Views in Wicket Viewer.
• Site-Map Export (AsciiDoc).
• Application Logo availability via REST.

Notable Improvements

• @DomainObject is no longer allowed on Interfaces.
• Removed LocaleProvider in favor of InteractionContext for i18n.
• @XmlJavaTypeAdapter on properties is now optional if the referenced type already has it.
• Support for generic Value-Type Conversion based on ValueSemantics in Wicket Viewer.

The 2.0.0-RC1 release introduces several key features and architectural changes:

• PageRenderSubscriber SPI: A new Service Provider Interface that provides callbacks to track the time taken to render a page.
• Enhanced Permissions: SAFE semantics actions can now be invoked with only VIEWING permission.
• HTML Documentation Service: A new service based on the domain model.
• BackgroundService: A new service for handling background tasks.
• ViewModel Injection: ViewModel implementations now support using Injection Points during construction.
• CommandPublisher Callbacks: Additional callbacks are available for when a command is created or started, and CommandLogEntry is now persisted at the beginning of the process.
• AsciiDoc PlantUML Support: Added support for PlantUML within AsciiDoc for Value Types.
• Customizable Layouts: DomainObjectLayout#tableDecoration has been refactored to allow for customization.

The MetaModelService provides a formal API to inspect the framework's metamodel. It allows you to look up domain types (via names or classes), retrieve aliases, inspect the domain model, and export the metamodel or object graphs for external tools like PlantUML.

interface MetaModelService {
  Optional<LogicalType> lookupLogicalTypeByName(String logicalTypeName);
  Can<LogicalType> logicalTypeAndAliasesFor(LogicalType logicalType);
  Can<LogicalType> logicalTypeAndAliasesFor(String logicalTypeName);
  Optional<LogicalType> lookupLogicalTypeByClass(Class<?> domainType);
  void rebuild(Class<?> domainType);
  DomainModel getDomainModel();
  BeanSort sortOf(Class<?> domainType, Mode mode);
  BeanSort sortOf(Bookmark bookmark, Mode mode);
  CommandDtoProcessor commandDtoProcessorFor(String logicalMemberIdentifier);
  MetamodelDto exportMetaModel(Config config);
  ObjectGraph exportObjectGraph(BiPredicate<BeanSort, LogicalType> filter);
}

Apache Causeway provides a wide range of Domain Services (applib-svc) that handle core application logic, infrastructure, and UI support. These services are categorized into several functional areas:

• Command & Execution: Services for executing commands and processing DTOs, including CommandExecutorService, CommandDtoProcessorService, and various subscribers like CommandSubscriber.
• Content & Mapping: Tools for managing content and data transformations, such as ContentMappingService and ContentMappingServiceForCommandDto.
• User & Security: Services for managing users, sessions, and permissions, including UserService, SessionSubscriber, SudoService, and ImpersonateMenu.
• UI & Navigation: Components for building user interfaces, such as MenuBarsService, LayoutService, SitemapService, and ApplicationFeatureMenu.
• Data & Persistence: Support for data handling, including RepositoryService, GridService, QueryResultsCache, and specialized QueryDsl support like QueryDslRepository.
• Infrastructure: Core utilities like EventBusService, TransactionService, HealthCheckService, MetricsService, and ErrorReportingService.
• Internationalization (i18n): Services for localization, including LanguageProvider, TranslationService, and LocaleChoiceProvider.

Refer to the specific service documentation for detailed API signatures and usage patterns.

A Wrapper is a runtime-generated proxy that wraps a domain object to enforce the Apache Causeway programming model.

When you interact with a wrapped object via its get methods, set methods, or actions, the wrapper automatically enforces:

• Imperative constraints: Logic defined in hideXxx(), disableXxx(), and validateXxx() methods.
• Declarative constraints: Constraints defined via annotations, such as @Parameter(maxLength=...) or @Property(mustSatisfy=...).

If an interaction violates these rules, the wrapper throws an InteractionException (or a subclass like HiddenException or InvalidException).

Key Capabilities:

• Synchronous Execution: Enforce business rules immediately during method calls.
• Asynchronous Execution: Execute actions in a separate thread using an ExecutorService via asyncWrap.
• Mixin Support: Wrap objects with additional functionality using wrapMixin or wrapMixinT (typesafe).