Clojure Applied

Putting Things Together

In Component, a system is a special component that can start and stop other components. The components in a system are started in an order such that dependencies are always started before a component. This requires that no cycles are in the component dependency graph. Similarly, when a system is stopped, components are stopped in the reverse order of the start.

A system is defined with the component/system-map function. The map defines a mapping from component name to component instance. When a component has component dependencies, this is specified with component/using, which takes either a vector of injected components (if the names are the same in the system and inside the component) or a mapping from the component ...