Main components DI #

Library contain three main components:

• Scope
• Module
• Binding

Scope #

Scope is a container that stores the entire dependency tree (scope, modules, instances). Through the scope, you can access the custom instance, for this you need to call the resolve<T>() method and specify the type of the object, and you can also pass additional parameters.

Example:

    // open main scope
    final rootScope =  Cherrypick.openRootScope();

    // initializing scope with a custom module
    rootScope.installModules([AppModule()]);

    // takes custom instance
    final str = rootScope.resolve<String>();
    // or
    final str = rootScope.tryResolve<String>();

    // close main scope
    Cherrypick.closeRootScope();

Module #

Module is a container of user instances, and on the basis of which the user can create their modules. The user in his module must implement the void builder (Scope currentScope) method. Модули добавляются в Scope с помощью метода scope.installModules(…), после чего Scope может разрешать зависимости по правилам, определённым в его модулях.

Example:

class AppModule extends Module {
  @override
  void builder(Scope currentScope) {
    bind<ApiClient>().toInstance(ApiClientMock());
  }
}

Binding #

Binding is a custom instance configurator that contains methods for configuring a dependency.

There are two main methods for initializing a custom instance toInstance() and toProvide() and auxiliary withName() and singleton().

toInstance() - takes a initialized instance

toProvide() -  takes a provider function (instance constructor)

withName() - takes a string to name the instance. By this name, it will be possible to extract instance from the DI container

singleton() - sets a flag in the Binding that tells the DI container that there is only one dependency.

Example:

 // initializing a text string instance through a method toInstance()
 Binding<String>().toInstance("hello world");

 // or

 // initializing a text string instance
 Binding<String>().toProvide(() => "hello world");

 // initializing an instance of a string named
 Binding<String>().withName("my_string").toInstance("hello world");
 // or
 Binding<String>().withName("my_string").toProvide(() => "hello world");

 // instance initialization like singleton
 Binding<String>().toInstance("hello world");
 // or
 Binding<String>().toProvide(() => "hello world").singleton();