SimpleBinder

class SimpleBinder

Pure-Dart, map-based Binder implementation with no external dependencies.

SimpleBinder maintains two separate registration maps — private and public — to support the ExportableBinder contract. It also implements RegistrationAwareBinder for hot-reload support and DisposableBinder for resource cleanup.

Dependency resolution follows the order:

Local private scope
Local public scope
Imported binders (public exports only)
Parent binder

dart

final binder = SimpleBinder();
binder.registerLazySingleton<Logger>(() => ConsoleLogger());
binder.registerFactory<ApiClient>(() => ApiClient(binder.get<Logger>()));

final client = binder.get<ApiClient>(); // new instance each time

Constructors

SimpleBinder()

SimpleBinder({List<dynamic> imports = const [], dynamic parent})

Creates a SimpleBinder with optional imported binders and a parent scope for hierarchical resolution.

Implementation

dart

SimpleBinder({List<Binder> imports = const [], Binder? parent})
  : _imports = imports.toList(),
    _parent = parent;

Properties

hashCode no setter inherited

int get hashCode

The hash code for this object.

A hash code is a single integer which represents the state of the object that affects operator == comparisons.

All objects have hash codes. The default hash code implemented by Object represents only the identity of the object, the same way as the default operator == implementation only considers objects equal if they are identical (see identityHashCode).

If operator == is overridden to use the object state instead, the hash code must also be changed to represent that state, otherwise the object cannot be used in hash based data structures like the default Set and Map implementations.

Hash codes must be the same for objects that are equal to each other according to operator ==. The hash code of an object should only change if the object changes in a way that affects equality. There are no further requirements for the hash codes. They need not be consistent between executions of the same program and there are no distribution guarantees.

Objects that are not equal are allowed to have the same hash code. It is even technically allowed that all instances have the same hash code, but if clashes happen too often, it may reduce the efficiency of hash-based data structures like HashSet or HashMap.

If a subclass overrides hashCode, it should override the operator == operator as well to maintain consistency.

Inherited from Object.

Implementation

dart

external int get hashCode;

isExportModeEnabled no setter

bool get isExportModeEnabled

Return true when registrations are directed to the public scope.

Implementation

dart

@override
bool get isExportModeEnabled => _isExportMode;

isPublicScopeSealed no setter

bool get isPublicScopeSealed

Return true when the public scope is sealed and rejects new registrations.

Implementation

dart

@override
bool get isPublicScopeSealed => _publicSealed;

registrationStrategy no setter

dynamic get registrationStrategy

Return the currently active RegistrationStrategy.

Implementation

dart

@override
RegistrationStrategy get registrationStrategy => _strategyStack.last;

runtimeType no setter inherited

Type get runtimeType

A representation of the runtime type of the object.

Inherited from Object.

Implementation

dart

external Type get runtimeType;

Methods

addImports()

void addImports(List<dynamic> binders)

Append the given Binder list to the set of imported scopes.

Implementation

dart

@override
void addImports(List<Binder> binders) {
  _imports.addAll(binders);
}

contains()

bool contains(Type type)

Return true if type is registered in any reachable scope.

Checks local registrations, imported public exports, and the parent chain.

Implementation

dart

@override
bool contains(Type type) {
  &#47;&#47; 1. Local
  if (_privateRegistrations.containsKey(type) ||
      _publicRegistrations.containsKey(type)) {
    return true;
  }

  &#47;&#47; 2. Imports
  for (final importedBinder in _imports) {
    &#47;&#47; Correctly check only public exports for imports
    if (importedBinder is ExportableBinder) {
      if (importedBinder.containsPublic(type)) return true;
    } else {
      if (importedBinder.contains(type)) return true;
    }
  }

  &#47;&#47; 3. Parent
  if (_parent?.contains(type) == true) return true;

  return false;
}

containsPublic()

bool containsPublic(Type type)

Return true if type is registered in the public (exported) scope.

Implementation

dart

@override
bool containsPublic(Type type) {
  return _publicRegistrations.containsKey(type);
}

debugGraph()

String debugGraph({bool includeImports = false})

Returns a human-readable text dump of the current binder state, listing private and public registrations (and optionally imports).

Implementation

dart

String debugGraph({bool includeImports = false}) {
  final buffer = StringBuffer()
    ..writeln('SimpleBinder(${hashCode.toRadixString(16)})')
    ..writeln('  Private:')
    ..writeln(
      _privateRegistrations.keys
          .map((t) => '    - ${t.toString()}')
          .join('\n')
          .trimRight(),
    )
    ..writeln('  Public:')
    ..writeln(
      _publicRegistrations.keys
          .map((t) => '    - ${t.toString()}')
          .join('\n')
          .trimRight(),
    );

  if (includeImports && _imports.isNotEmpty) {
    buffer.writeln('  Imports:');
    for (final imported in _imports) {
      if (imported is SimpleBinder) {
        buffer.writeln(
          imported
              .debugGraph(includeImports: false)
              .split('\n')
              .map((line) => '    $line')
              .join('\n'),
        );
      } else {
        buffer.writeln('    - ${imported.runtimeType}');
      }
    }
  }

  return buffer.toString();
}

disableExportMode()

void disableExportMode()

Disable export mode (registrations go to the private scope).

Implementation

dart

@override
void disableExportMode() => _isExportMode = false;

dispose()

Future<void> dispose()

Release resources.

Implementation

dart

@override
Future<void> dispose() async {
  _privateRegistrations.clear();
  _publicRegistrations.clear();
  _publicSealed = false;
}

enableExportMode()

void enableExportMode()

Enable export mode (registrations go to the public scope).

Implementation

dart

@override
void enableExportMode() => _isExportMode = true;

get()

T get<T extends Object>()

Resolve a dependency of type T or throw DependencyNotFoundException.

Lookup order: local private scope, local public scope, imports, parent.

Implementation

dart

@override
T get<T extends Object>() {
  final object = tryGet<T>();
  if (object == null) {
    throw DependencyNotFoundException(
      'Dependency of type $T not found.\n'
      'Checked: Current Scope, Imports, Parent.',
      requestedType: T,
      availableTypes: [
        ..._privateRegistrations.keys,
        ..._publicRegistrations.keys,
      ],
    );
  }
  return object;
}

noSuchMethod() inherited

dynamic noSuchMethod(Invocation invocation)

Invoked when a nonexistent method or property is accessed.

A dynamic member invocation can attempt to call a member which doesn't exist on the receiving object. Example:

dart

dynamic object = 1;
object.add(42); // Statically allowed, run-time error

This invalid code will invoke the noSuchMethod method of the integer 1 with an Invocation representing the .add(42) call and arguments (which then throws).

Classes can override noSuchMethod to provide custom behavior for such invalid dynamic invocations.

A class with a non-default noSuchMethod invocation can also omit implementations for members of its interface. Example:

dart

class MockList<T> implements List<T> {
  noSuchMethod(Invocation invocation) {
    log(invocation);
    super.noSuchMethod(invocation); // Will throw.
  }
}
void main() {
  MockList().add(42);
}

This code has no compile-time warnings or errors even though the MockList class has no concrete implementation of any of the List interface methods. Calls to List methods are forwarded to noSuchMethod, so this code will log an invocation similar to Invocation.method(#add, [42]) and then throw.

If a value is returned from noSuchMethod, it becomes the result of the original invocation. If the value is not of a type that can be returned by the original invocation, a type error occurs at the invocation.

The default behavior is to throw a NoSuchMethodError.

Inherited from Object.

Implementation

dart

@pragma("vm:entry-point")
@pragma("wasm:entry-point")
external dynamic noSuchMethod(Invocation invocation);

parent()

T parent<T extends Object>()

Resolve a dependency of type T from the parent scope or throw.

Implementation

dart

@override
T parent<T extends Object>() {
  final object = tryParent<T>();
  if (object == null) {
    throw DependencyNotFoundException(
      'Dependency of type $T not found in parent scope.',
      requestedType: T,
      lookupContext: 'parent scope',
    );
  }
  return object;
}

registerFactory()

void registerFactory<T extends Object>(T Function() factory)

Implementation

dart

@override
void registerFactory<T extends Object>(T Function() factory) {
  _register<T>(
    _Registration(type: _DependencyType.factory, factory: factory),
  );
}

registerLazySingleton()

void registerLazySingleton<T extends Object>(T Function() factory)

Implementation

dart

@override
void registerLazySingleton<T extends Object>(T Function() factory) {
  _register<T>(
    _Registration(type: _DependencyType.singleton, factory: factory),
  );
}

registerSingleton()

void registerSingleton<T extends Object>(T instance)

Implementation

dart

@override
void registerSingleton<T extends Object>(T instance) {
  _register<T>(
    _Registration(
      type: _DependencyType.instance,
      factory: () => instance,
      instance: instance,
    ),
  );
}

resetPublicScope()

void resetPublicScope()

Unseal the public scope to allow re-registration (e.g. during hot reload).

Implementation

dart

@override
void resetPublicScope() {
  _publicSealed = false;
}

runWithStrategy()

T runWithStrategy<T>(dynamic strategy, T Function() body)

Execute body under the given RegistrationStrategy, restoring the previous strategy when body completes.

Implementation

dart

@override
T runWithStrategy<T>(RegistrationStrategy strategy, T Function() body) {
  _strategyStack.add(strategy);
  try {
    return body();
  } finally {
    _strategyStack.removeLast();
  }
}

sealPublicScope()

void sealPublicScope()

Seal the public scope so that further export-mode registrations throw.

Implementation

dart

@override
void sealPublicScope() {
  _publicSealed = true;
}

toString() inherited

String toString()

A string representation of this object.

Some classes have a default textual representation, often paired with a static parse function (like int.parse). These classes will provide the textual representation as their string representation.

Other classes have no meaningful textual representation that a program will care about. Such classes will typically override toString to provide useful information when inspecting the object, mainly for debugging or logging.

Inherited from Object.

Implementation

dart

external String toString();

tryGet()

T? tryGet<T extends Object>()

Try to resolve a dependency of type T, returning null if not found.

Searches local scope, then imports (public exports only), then parent.

Implementation

dart

@override
T? tryGet<T extends Object>() {
  &#47;&#47; 1. Search locally (Private first, then Public)
  if (_privateRegistrations.containsKey(T)) {
    return _resolveRegistration<T>(_privateRegistrations[T]!);
  }
  if (_publicRegistrations.containsKey(T)) {
    return _resolveRegistration<T>(_publicRegistrations[T]!);
  }

  &#47;&#47; 2. Search in imports (ONLY Public exports of imported modules)
  for (final importedBinder in _imports) {
    if (importedBinder is ExportableBinder) {
      final found = importedBinder.tryGetPublic<T>();
      if (found != null) return found;
    } else {
      final found = importedBinder.tryGet<T>();
      if (found != null) return found;
    }
  }

  &#47;&#47; 3. Search in Parent (Implicit scope chaining)
  &#47;&#47; Search parent as a regular get (it decides its own access rights)
  final parentFound = _parent?.tryGet<T>();
  if (parentFound != null) return parentFound;

  return null;
}

tryGetPublic()

T? tryGetPublic<T extends Object>()

Searches ONLY in public dependencies (for use by other modules).

Implementation

dart

@override
T? tryGetPublic<T extends Object>() {
  if (_publicRegistrations.containsKey(T)) {
    return _resolveRegistration<T>(_publicRegistrations[T]!);
  }
  return null;
}

tryParent()

T? tryParent<T extends Object>()

Try to resolve a dependency of type T from the parent scope.

Implementation

dart

@override
T? tryParent<T extends Object>() {
  return _parent?.tryGet<T>();
}

Operators

operator ==() inherited

bool operator ==(Object other)

The equality operator.

The default behavior for all Objects is to return true if and only if this object and other are the same object.

Override this method to specify a different equality relation on a class. The overriding method must still be an equivalence relation. That is, it must be:

Total: It must return a boolean for all arguments. It should never throw.
Reflexive: For all objects o, o == o must be true.
Symmetric: For all objects o1 and o2, o1 == o2 and o2 == o1 must either both be true, or both be false.
Transitive: For all objects o1, o2, and o3, if o1 == o2 and o2 == o3 are true, then o1 == o3 must be true.

The method should also be consistent over time, so whether two objects are equal should only change if at least one of the objects was modified.

If a subclass overrides the equality operator, it should override the hashCode method as well to maintain consistency.

Inherited from Object.

Implementation

dart

external bool operator ==(Object other);

SimpleBinder ​

Constructors ​

SimpleBinder() ​

Properties ​

hashCode no setter inherited ​

isExportModeEnabled no setter ​

isPublicScopeSealed no setter ​

registrationStrategy no setter ​

runtimeType no setter inherited ​

Methods ​

addImports() ​

contains() ​

containsPublic() ​

debugGraph() ​

disableExportMode() ​

dispose() ​

enableExportMode() ​

get() ​

noSuchMethod() inherited ​

parent() ​

registerFactory() ​

registerLazySingleton() ​

registerSingleton() ​

resetPublicScope() ​

runWithStrategy() ​

sealPublicScope() ​

toString() inherited ​

tryGet() ​

tryGetPublic() ​

tryParent() ​

Operators ​

operator ==() inherited ​

SimpleBinder

Constructors

SimpleBinder()

Properties

hashCode no setter inherited

isExportModeEnabled no setter

isPublicScopeSealed no setter

registrationStrategy no setter

runtimeType no setter inherited

Methods

addImports()

contains()

containsPublic()

debugGraph()

disableExportMode()

dispose()

enableExportMode()

get()

noSuchMethod() inherited

parent()

registerFactory()

registerLazySingleton()

registerSingleton()

resetPublicScope()

runWithStrategy()

sealPublicScope()

toString() inherited

tryGet()

tryGetPublic()

tryParent()

Operators

operator ==() inherited