High Level Architecture

High-level architecture

QQQ 4.0 release. Final 4.0.0 is available. See QQQ 4.0 for release scope and migration guidance.

QQQ applications combine Java metadata and application code. QInstance contains tables, backends, processes, apps, and other metadata. Actions operate through typed input/output contracts; Java BackendStep classes implement process behavior.

flowchart LR
  Metadata[QInstance metadata] --> Middleware[Configured application entry points]
  Middleware --> Actions[QQQ actions and process steps]
  Actions --> Backends[Backend-specific implementations]
  Backends --> Data[Application data sources]
  Metadata --> Dashboard[Material Dashboard 0.41.0]

Loading

QContext holds thread-local execution state. Application entry points establish context; code that initializes its own context must also clear it. Backends implement QBackendModuleInterface and operation-specific interfaces. Supported operations vary by backend.

Metadata producers assemble application definitions; they are Java interfaces with contracts in the selected source. Table metadata does not automatically create the SQL schema. Configure authentication, permissions, validation, and operational controls for the application and test them through every relevant entry point.

See Core Modules, Public API Overview, and the source reference.