Analysis

Compare patterns

Evaluate design patterns side by side across intent, tradeoffs, languages, and integration fit.

Choose patterns

Select up to 3 patterns

Current selection

3 of 3 selected

You can now review the differences across the comparison table below.

Analysis

Pattern comparison

Reviewing 3 patterns.

Criteria
creationalFactory MethodView pattern
behavioralIteratorView pattern
behavioralObserverView pattern
Basics
Categorycreationalbehavioralbehavioral
Summary———
IntentDefine a creation method behind a common interface so specialized creators can decide which concrete product to instantiate without changing the surrounding workflow.Provide a way to access elements of an aggregate sequentially while hiding the underlying representation.Define a subscription mechanism so multiple observers can react to subject events without the subject knowing concrete subscriber details.
Decision factors
ProblemA workflow needs to create one of several related concrete objects, but constructing them directly in client code spreads creation logic and tightly couples the caller to specific implementations.A collection needs to be traversed without exposing how it is stored internally.A system needs to notify multiple dependent objects when state changes occur, but hardcoding those dependencies makes the design rigid and tightly coupled.
Tradeoffs
  • Adds extra indirection and more types compared with direct construction
  • Can feel unnecessarily abstract when object creation is simple and unlikely to vary
  • Can add extra classes and abstraction for simple collections
  • May be unnecessary when built-in language iteration is already enough
  • Notification flows can become hard to trace when many observers react to the same event
  • Observers may receive updates they do not need unless subscriptions are carefully designed
Practical fit
Languages
  • typescript
  • java
  • python
  • angular
  • react
  • react-native
  • csharp
  • dotnet
  • typescript
  • java
  • python
  • angular
  • react
  • react-native
  • csharp
  • dotnet
  • typescript
  • java
  • python
  • angular
  • react
  • react-native
  • csharp
  • dotnet
Platforms
  • Applications
  • APIs
  • Frameworks
  • Service layers
  • Web
  • Backend
  • Mobile
  • UI kits
  • Cross-platform systems
  • Web
  • Backend
  • Event-driven systems
Integration notesFactory Method is useful when framework hooks, integrations, or environment-specific workflows need to create interchangeable implementations behind a stable contract.Iterator is useful for pagination, custom collections, ordered traversal, and any case where clients should not know the internal data structure.Observers work well inside a single application boundary for UI events, domain events, and in-process notifications where subscribers change dynamically.