class ara::diag::Event

In AUTOSAR Adaptive, the class ara::diag::Event provides operations for monitoring diagnostic events and their debouncing and error status. Applications instantiate the object via an InstanceSpecifier, register optional change notifications, and retrieve diagnostic and DTC information asynchronously [SWS_DM_00647]. As a central constraint, the instance is neither copyable nor movable, and due to a lack of thread safety, most query methods require application-side synchronization during concurrent access [SWS_DM_00649].

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Context

The class ara::diag::Event serves as the primary interface for interacting with diagnostic events in the AUTOSAR Adaptive Platform. It acts as a link between application-specific software and central diagnostic management. Applications use this interface to monitor the current diagnostic and debouncing status of an event or to be notified of status changes.

In the system context, essentially three parties are involved in the interaction:

• Application software: Instantiates the class, initiates status queries, and receives asynchronous status updates.
• ara::diag::Event: Encapsulates the typed diagnostic port (PortPrototype of a DiagnosticEventInterface) and provides cross-thread and cross-process query methods.
• Diagnostic Management (DM): Executes error detection, DTC mappings, and debouncing behavior on the server side.

Context diagram: Placement of the Event class between application software and Diagnostic Management. Sources: [SWS_DM_00647], [SWS_DM_00653]

Lifecycle

Instantiation is performed explicitly by passing an ara::core::InstanceSpecifier [SWS_DM_00647]. The identifier must refer to a PortPrototype typed via an DiagnosticEventInterface. The constructor is exception-safe and thread-safe [SWS_DM_00647].

With regard to ownership, ara::diag::Event is defined as a non-copyable and non-movable single instance: both the copy constructor [SWS_DM_01681] and the move constructor [SWS_DM_01682] as well as the associated assignment operators ([SWS_DM_01679], [SWS_DM_01680]) are explicitly deleted (=delete). An InstanceSpecifier must not be instantiated multiple times per process [SWS_DM_00647].

Destruction takes place via the destructor ~Event() [SWS_DM_00648]. Unlike the constructor, the destructor is not thread-safe. The remaining member functions (with the exception of GetDTCNumber) are also specified as not thread-safe, which is why concurrent calls on the same instance must be synchronized on the application side. In Release R25-11, the terminology in this regard was harmonized from reentrancy to concurrency AUTOSAR_AP_SWS_Diagnostics §1 “Change History”.

Usage Path

A typical use case is divided into the following calls:

1. Initialization: The application creates the instance via its InstanceSpecifier [SWS_DM_00647]. The binding is expected to establish the connection to the diagnostic daemon at initialization time. Question Q-78e4462a0d147cfb (open)
2. Registering notifier: For monitoring purposes, a callback is optionally registered via SetEventStatusChangedNotifier [SWS_DM_00650]. A subsequent call overwrites the previously set notifier.
3. State queries: During operation, the application queries diagnostic data asynchronously via ara::core::Future:
   • GetEventStatus() determines the current status byte [SWS_DM_00649].
   • GetDebouncingStatus() returns the current debouncing state [SWS_DM_00654].
   • GetFaultDetectionCounter() retrieves the fault detection counter (FDC) [SWS_DM_00656].
   • GetTestComplete() checks whether the test has completed (FDC reaches -128 or 127) [SWS_DM_00655].
   • GetDTCNumber(dtcFormat) provides the associated DTC number in the selected format and is designed to be thread-safe [SWS_DM_00653].

Sequence diagram: Typical interaction sequence between application, event instance, and Diagnostic Management. Sources: [SWS_DM_00647], [SWS_DM_00650], [SWS_DM_00649], [SWS_DM_00653]

Error Scenarios

Error conditions occur in the form of modeling violations upon instantiation or as error codes at runtime:

• Violations during constructor invocation [SWS_DM_00647]:
  • InstanceSpecifierMappingIntegrityViolation: The identifier cannot be resolved in the model or does not reference a PortPrototype.
  • PortInterfaceMappingViolation: The referenced PortPrototype is not typed as DiagnosticEventInterface.
  • ProcessMappingViolation: No modeled context matching the process was found.
  • InstanceSpecifierAlreadyInUseViolation: The identifier is already used by an active instance in the same process.
• Runtime error codes via ara::core::Result or ara::core::Future:
  • DiagErrc::kServiceNotAvailable: Occurs for all status queries ([SWS_DM_00649], [SWS_DM_00653], [SWS_DM_00654], [SWS_DM_00655], [SWS_DM_00656]) if essential background functions of Diagnostic Management are unavailable. Communication is likely handled asynchronously via IPC. Question (open)
  • DiagErrc::kNoSuchDTC: Reported by GetDTCNumber if no DTC is configured for the event [SWS_DM_00653].
  • DiagErrc::kInvalidArgument: Returned by SetEventStatusChangedNotifier, for example in the case of invalid input values [SWS_DM_00650].