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
behavioralObserverView pattern
structuralProxyView pattern
Basics
Categorycreationalbehavioralstructural
Summary———
IntentDefine a creation method behind a common interface so specialized creators can decide which concrete product to instantiate without changing the surrounding workflow.Define a subscription mechanism so multiple observers can react to subject events without the subject knowing concrete subscriber details.Provide a surrogate or placeholder for another object to control access to it.
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 system needs to notify multiple dependent objects when state changes occur, but hardcoding those dependencies makes the design rigid and tightly coupled.A client needs to interact with an object indirectly because the real object may be expensive, sensitive, or remote.
Tradeoffs
  • Adds extra indirection and more types compared with direct construction
  • Can feel unnecessarily abstract when object creation is simple and unlikely to vary
  • 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
  • Adds another layer of indirection
  • Can make the design more complex when the extra control is unnecessary
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
  • Event-driven systems
  • Web
  • Backend
  • Mobile
  • UI kits
  • Cross-platform systems
Integration notesFactory Method is useful when framework hooks, integrations, or environment-specific workflows need to create interchangeable implementations behind a stable contract.Observers work well inside a single application boundary for UI events, domain events, and in-process notifications where subscribers change dynamically.Proxy is useful for lazy loading, access control, caching, logging, and remote service wrappers.