php-patterns

PHP Design Patterns

Before writing code

Fetch live docs: Web-search php design patterns examples for current community patterns and best practices. For Magento-specific patterns, web-search site:developer.adobe.com commerce php development components.

Creational Patterns

Factory

Creates objects without exposing instantiation logic. In Magento, auto-generated Factory classes (SomeModelFactory) create non-injectable objects via $factory->create().

When to use: When you need new instances (entities, models) rather than shared singletons. When the caller shouldn't know the concrete class.

Builder

Constructs complex objects step by step. Magento's SearchCriteriaBuilder, FilterBuilder, SortOrderBuilder follow this pattern.

When to use: When object construction requires many optional parameters or multi-step assembly.

Singleton (Shared Instance)

Single instance shared across the application. Magento's Object Manager shares instances by default. Explicit singleton is generally an anti-pattern — prefer DI container sharing.

When to use: Rarely — let the DI container manage instance sharing.

Structural Patterns

Proxy

Delays instantiation of resource-intensive dependencies. Magento auto-generates Proxy classes (SomeClass\Proxy) that create the real object only when a method is called.

When to use: When a class injects a heavy dependency it doesn't always use.

Decorator

Wraps an object to add behavior without modifying the original. Used in Magento composite components and cache decorators.

When to use: When you need to add behavior to an object dynamically without subclassing.

Composite

Treats individual objects and compositions uniformly. Magento's UI component tree and layout container system follow this pattern.

When to use: When you have tree-structured data or components.

Behavioral Patterns

Strategy

Defines a family of algorithms, encapsulates each one, makes them interchangeable. Magento shipping carriers and payment methods are strategy implementations.