generateForAnnotatedElement method

@override FutureOr<String> generateForAnnotatedElement(Element element, ConstantReader annotation, BuildStep buildStep)

Implement to return source code to generate for element.

This method is invoked based on finding elements annotated with an instance of T. The annotation is provided as a ConstantReader.

Supported return values include a single String or multiple String instances within an Iterable or Stream. It is also valid to return a Future of String, Iterable, or Stream. When multiple values are returned through an iterable or stream they will be deduplicated. Typically each value will be an independent unit of code and the deduplication prevents re-defining the same member multiple times. For example if multiple annotated elements may need a specific utility method available it can be output for each one, and the single deduplicated definition can be shared.

Implementations should return null when no content is generated. Empty or whitespace-only String instances are also ignored.

Implementation

@override
FutureOr<String> generateForAnnotatedElement(
  Element element,
  ConstantReader annotation,
  BuildStep buildStep,
) async {
  // Helpful diagnostics
  log.info('SotiSchema: processing class ${element.displayName}');
  // Check if element is a ClassElement
  if (element is! ClassElement) {
    throw InvalidGenerationSourceError(
      'SotiSchema can only be applied to classes: ${element.displayName}',
    );
  }

  final buffer = StringBuffer();

  // Use Element API to get all getters
  for (final getter in element.getters) {
    if (!getter.isStatic) continue;

    // Check for JsonSchema annotation using the metadata API
    final hasJsonSchema = getter.metadata.annotations.any((anno) {
      final value = anno.computeConstantValue();
      if (value == null || value.type == null) return false;
      return _typeCheckers.jsonSchemaChecker.isExactlyType(value.type!);
    });

    if (hasJsonSchema) {
      log.fine(
        'SotiSchema: found @jsonSchema getter ${getter.displayName} in ${element.displayName}',
      );
      final schema = _schemaGenerator.generateSchema(element);
      final name = await _getRedirectedVariableName(getter, buildStep);
      if (name == null) {
        throw InvalidGenerationSourceError(
          'Failed to extract redirected variable name for ${getter.displayName}.',
        );
      }
      _writeSchemaToBuffer(buffer, name, getter.returnType, schema);
    }
  }

  return buffer.toString();
}