setproviding

Setproviding is a term used in dependency-injection (DI) systems to describe the pattern of supplying a collection of bindings as a single injectable value. It is commonly implemented through multibindings that contribute to a Set<T>, allowing multiple providers to supply individual elements that are gathered into one set injected into a consumer.

Contributors register bindings for elements of type T; the DI container aggregates these into a Set<T> during resolution, and the consumer receives the complete set. Depending on the framework, the produced Set may be immutable, and the element order may be defined or unspecified.

Examples and implementations vary by framework. In Dagger, multibindings can form a Set<T> by using a provider method annotated with @Provides and @IntoSet, contributing elements to the set. Guice offers a similar mechanism through Multibinder, which creates a Set binding and allows multiple bindings to be added to that set.

Benefits of setproviding include modularity and extensibility, as modules can contribute implementations without direct dependencies on each other. It supports plug-in architectures and dynamic composition where a consumer can evolve to accept new elements without code changes.

Drawbacks include added complexity in the DI configuration, potential nondeterminism in the order of set elements, and possible performance overhead during set construction if many contributors are involved.

See also: dependency injection, multibindings, set binding, Dagger, Guice.