spring_core_dart_generator 0.1.5

Code generator for spring_core_dart: turns @Component, @Bean, @Value, @Aspect and other annotations into bean definitions, metadata and AOP proxies.

example/README.md

spring_core_dart_generator: examples

What it does: reads the annotations of spring_core_dart (@Service, @Value, @Bean, @Aspect...) and writes plain Dart code that creates and connects your objects. Dart has no runtime reflection (and Flutter forbids it), so this step happens at build time. It is required: without it the annotations do nothing.

Setup

dependencies:
  spring_core_dart: ^0.1.0

dev_dependencies:
  build_runner: ^2.17.0
  spring_core_dart_generator: ^0.1.0

Mark the scan root — every class under lib/src/ is scanned:

// lib/src/app.dart
import 'package:spring_core_dart/spring_core_dart.dart';
import 'app.beans.dart'; // created by the generator

@ComponentScan()
final BeanModule appBeans = $appBeans;

With spring_boot_dart you skip this file: put @SpringBootApplication() on main instead.

Run it

dart run build_runner build   # once
dart run build_runner watch   # regenerate on every save

It writes app.beans.dart next to app.dart. Commit generated files: then the app builds without running the generator first (CI, other developers).

What it writes

You write:

@Service()
class Greeter {
  Greeter(@Value(r'${greeting.suffix:!}') this.suffix, this.clock);
  final String suffix;
  final Clock clock;
}

It generates (simplified):

final BeanModule $appBeans = BeanModule('appBeans', [
  BeanDefinition<Greeter>(
    name: 'greeter',
    dependencies: const [
      Dependency.value(r'${greeting.suffix:!}'),
      Dependency(Clock, name: r'clock'),
    ],
    create: (r) => Greeter(
      r.value<String>(r'${greeting.suffix:!}'),
      r.dependency<Clock>(name: r'clock'),
    ),
  ),
]);

Plain constructor calls and closures: fast, works in AOT, Flutter and on the web, and survives minification.

Mistakes are build errors, not crashes

The generator checks what it can before the app ever runs:

@Service()
class Report {
  @Autowired()
  final Clock clock;   // ✗ "Injected field clock must be settable: declare it late final or non-final."
}

@Service()
class Inbox {
  @Autowired()
  late final Mailer _mailer;   // ✗ "Injected field _mailer must be public."
}

@Service()
class Shop {
  Shop(@Lazy() this.repo);
  final Repository<Book>? repo;  // ✗ "a lazy dependency cannot be nullable; use ObjectProvider<...>"
}

Missing or ambiguous beans and dependency cycles are reported when the context starts — before any of your objects is created.

Options

# build.yaml of your package
targets:
  $default:
    builders:
      spring_core_dart_generator:spring_core_dart:
        options:
          aop_proxies: all   # all (default) | interfaces | none

aop_proxies controls the generated proxies used by @Aspect advice: interfaces proxies only interfaces (smaller code), none turns AOP off.

Resources

Files in lib/resources/ are embedded into the generated code, so classpath:application.properties and @Value('classpath:logo.png') work everywhere without declaring Flutter assets.

More

• What every annotation means: spring_core_dart example.
• A full app and its generated code: example/ in the repository (lib/src/app.beans.dart, bin/shop.beans.dart).