hkj-optics

To update deeply nested immutable Java records without manual copy methods, you use generated optics to perform type-safe, path-based data manipulation. This approach eliminates error-prone copy-and-set logic by enabling fluent deep navigation through complex hierarchies.

Optics in Java are abstractions like Lenses, Prisms, and Traversals that handle immutable data navigation by composing paths through nested records and collections. They enable targeted updates on specific fields without mutating the original data structure.

You generate type-safe lenses for Java record hierarchies by applying simple annotations to your records and interfaces. This annotation-driven code generation automatically creates the necessary optics to satisfy compile-time safety and total immutability requirements.

Yes, you can use Traversals to update a specific element within a collection of Java records. The generated optics support collection-based data patterns, allowing you to chain focus paths through lists and perform targeted modifications type-safely.

Yes, annotation-driven code generation for optics works with Java sum types by generating Prisms. These optics allow you to safely navigate and manipulate variant-specific data within your hierarchical domain models during compilation.

The best way to navigate complex nested domain models immutably is using a fluent Focus DSL to chain paths through nested records, collections, and optional fields. This provides expressive, type-safe data manipulation without manual boilerplate.