Parameter Forest

_{Published: 28 April 2025}

Known Uses

Widely used, the Parameter Forest pattern consists of multiple Parameter Trees. A Parameter Tree has a single dedicated root node, while a Parameter Forest has multiple root nodes.

Examples:

• GET /customers/abc123 – returns a tree (a single root with structured data)
• GET /customers/ – returns a forest (multiple trees, each representing a customer)

Discussion Input

As noted in the book (p. 157), introducing an artificial root node can transform a forest into a tree. This raises the question: what is the added value of identifying the Parameter Tree as a distinct pattern?

Furthermore, one might argue that recursive Parameter Trees and atomic Parameters are sufficient to describe complex data structures — meaning only two patterns instead of four, would be needed.

However, explicitly identifying all four patterns as fundamental building blocks enhances design awareness, as these patterns are frequently used in practice (even unconsciously :-).