pyqt_reactive.services.parameter_service_abc

Abstract base class for parameter services with auto-discovery dispatch.

This module provides a unified pattern for all services that operate on parameters based on their ParameterInfo type. It eliminates code duplication and enforces consistent architecture across all parameter services.

Key features: 1. Auto-discovery of handler methods based on naming convention 2. Type-safe dispatch using ParameterInfo discriminated unions 3. Zero boilerplate - just define handler methods 4. Consistent pattern across all services

Pattern:

Instead of:

class MyService:

def process(self, info):

if isinstance(info, OptionalDataclassInfo):

# handle optional dataclass

elif isinstance(info, DirectDataclassInfo):

# handle direct dataclass

else:

# handle generic

Use:

class MyService(ParameterServiceABC):

def _get_handler_prefix(self) -> str:

return ‘_process_’

def _process_OptionalDataclassInfo(self, info, …):

# Type checker knows info is OptionalDataclassInfo! …

def _process_DirectDataclassInfo(self, info, …):

# Type checker knows info is DirectDataclassInfo! …

def _process_GenericInfo(self, info, …):

# Type checker knows info is GenericInfo! …

Services using this pattern: - ParameterResetService: _reset_OptionalDataclassInfo, etc. - NestedValueCollectionService: _collect_OptionalDataclassInfo, etc. - Future services: just inherit and define handlers

Architecture benefits: - Single source of truth for dispatch logic - No if-elif-else chains - No manual registry maintenance - Type-safe (type checker narrows in each handler) - Adding new ParameterInfo type = add handler method to all services

Classes

ParameterServiceABC()

Abstract base for parameter services with auto-discovery dispatch.

class pyqt_reactive.services.parameter_service_abc.ParameterServiceABC

Abstract base for parameter services with auto-discovery dispatch.

Subclasses must: 1. Implement _get_handler_prefix() to return method prefix (e.g., ‘_reset_’) 2. Define handler methods following naming convention: {prefix}{ClassName}

The ABC automatically discovers all handler methods and provides type-safe dispatch via the dispatch() method.

Examples

class ResetService(ParameterServiceABC):

def _get_handler_prefix(self) -> str:

return ‘_reset_’

def reset_parameter(self, manager, param_name: str):

info = manager.form_structure.get_parameter_info(param_name) self.dispatch(info, manager)

def _reset_OptionalDataclassInfo(self, info: OptionalDataclassInfo, manager):

# Handler for Optional[Dataclass] parameters …

def _reset_DirectDataclassInfo(self, info: DirectDataclassInfo, manager):

# Handler for direct Dataclass parameters …

def _reset_GenericInfo(self, info: GenericInfo, manager):

# Handler for generic parameters …

__init__()

Initialize service and auto-discover handler methods.

Discovers all methods matching the pattern: {prefix}{ClassName} where prefix is returned by _get_handler_prefix().

dispatch(info: OptionalDataclassInfo | InlineDataclassWidgetInfo | DirectDataclassInfo | GenericInfo, *args, **kwargs) → Any

Auto-dispatch to handler based on ParameterInfo class name.

This method provides type-safe dispatch without if-elif-else chains. The type checker can narrow the type in each handler method.

Parameters:

• info – ParameterInfo instance (discriminated union)

• *args – Additional positional arguments passed to handler

• **kwargs – Additional keyword arguments passed to handler

Returns:

Result from handler method

Raises:

ValueError – If no handler found for ParameterInfo type

Examples

>>> service = ResetService()
>>> info = OptionalDataclassInfo(...)
>>> service.dispatch(info, manager)  # Calls _reset_OptionalDataclassInfo

has_handler(info: OptionalDataclassInfo | InlineDataclassWidgetInfo | DirectDataclassInfo | GenericInfo) → bool

Check if a handler exists for the given ParameterInfo type.

Useful for conditional logic or validation.

Parameters:

info – ParameterInfo instance to check

Returns:

True if handler exists, False otherwise

get_supported_types() → list[str]

Get list of supported ParameterInfo type names.

Useful for debugging and validation.

Returns:

List of class names that have handlers