coconstructors

Coconstructors are a programming concept used to describe the coordinated initialization of related objects or components via multiple constructors. They are not a formal language feature in most languages but a pattern that guides how constructors are designed to preserve invariants across parts of an object graph or resource set.

Common approaches rely on existing language features such as constructor chaining, delegating constructors, or factory methods. For related objects, a factory or wrapper is often employed to create and connect all parts atomically, ensuring that either all parts are initialized or none are.

Typical use cases include composite or aggregate objects that contain several resources, where the resources must share lifecycles or satisfy joint invariants; and cases where initialization steps must be performed in a specified order to guarantee correctness.

Advantages of coconstructors include stronger guarantees about object state and easier reasoning about initialization. Drawbacks include increased coupling between components and potential boilerplate or indirection, which can complicate testing and maintenance.

Related concepts include constructors, overloading, and factory methods; examples are provided in language-specific patterns for multi-part initialization.