Summary

Pattern Comparison

Pattern	When to Apply	Strengths	Caveats	Common Use Cases
Facade	When you want to consolidate complex steps	Provides a simple interface for external callers	Can overly hide internal structure	Service orchestration, domain workflows
Proxy	When you want to inject behavior into calls	Adds functionality without changing call semantics	May introduce unnecessary complexity	Authorization, caching, logging
Iterator	When iteration logic is repeated or exposed	Abstracts collection traversal, enforces consistency	Overhead may be unnecessary for small use cases	Task lists, paging, structure traversal

Choosing the Right Pattern

• Use Facade to wrap complex procedures behind a simplified interface.
• Use Proxy to intercept or augment behavior without changing the public API.
• Use Iterator when traversal logic is repeated or tightly coupled with clients.

Note: Iterator is often used alongside Facade or Proxy
to unify traversal logic within abstracted control flow.

Team Discussion Snippets

• “This process exposes everything—auth, logging, etc. Let’s wrap it in a Facade for clarity.”
• “We want to keep the call the same but insert logging and permissions—sounds like a Proxy use case.”
• “Let’s define a clear interface here so changes won’t ripple outward.”
• “These repeated for loops are cluttering things—let’s encapsulate them using an Iterator.”