Analysis

Compare patterns

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

Choose patterns

Select up to 3 patterns

Abstract FactoryAdapterBridgeBuilderChain of ResponsibilityCommandCompositeDecoratorFacadeFactory MethodFlyweightInterpreterIteratorMediatorMementoObserverPrototypeProxySingletonStateStrategyTemplate MethodVisitor

Current selection

3 of 3 selected

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

Clear all

Analysis

Pattern comparison

Reviewing 3 patterns.

Criteria
behavioralObserverView pattern
behavioralStateView pattern
behavioralVisitorView pattern
Basics
Categorybehavioralbehavioralbehavioral
Summary———
IntentDefine a subscription mechanism so multiple observers can react to subject events without the subject knowing concrete subscriber details.Allow an object to alter its behavior when its internal state changes by delegating state-specific behavior to separate state objects.Separate an algorithm from the object structure it operates on by moving behavior into visitor objects.
Decision factors
ProblemA system needs to notify multiple dependent objects when state changes occur, but hardcoding those dependencies makes the design rigid and tightly coupled.An object behaves differently depending on its internal state, and conditional logic is becoming hard to manage.You need to perform operations across a set of different object types without stuffing all the logic into the objects themselves.
Tradeoffs
  • 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
  • Can introduce many small classes if the state graph is large
  • State transitions may become harder to trace if spread across multiple classes
  • Requires updating the visitor interface when new element types are added
  • Can be awkward if the object structure changes often
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
  • Web
  • Backend
  • Event-driven systems
  • Web
  • Backend
  • Mobile
  • UI kits
  • Cross-platform systems
  • Web
  • Backend
  • Mobile
  • UI kits
  • Cross-platform systems
Integration notesObservers work well inside a single application boundary for UI events, domain events, and in-process notifications where subscribers change dynamically.State is useful for workflows, media players, order lifecycles, and any domain where behavior changes as the object moves through a lifecycle.Visitor is useful for AST processing, reporting, cart calculations, and exporting object structures to alternate formats.