Facade Design Pattern in Java
Provide one simple entry point to a complex subsystem.
What is Facade?
Facade hides the order and details of several service calls. Clients use a small API instead of learning every subsystem class.
Beginner-friendly Java example
The following example shows the central idea of this pattern in a small, practical scenario.
class Inventory { void reserve(String item) { } }
class Payment { void charge(double amount) { } }
class Shipping { void ship(String item) { } }
class OrderFacade {
private final Inventory inventory = new Inventory();
private final Payment payment = new Payment();
private final Shipping shipping = new Shipping();
void placeOrder(String item, double amount) {
inventory.reserve(item);
payment.charge(amount);
shipping.ship(item);
}
}Benefits and trade-offs
Benefits
- Separates responsibilities clearly.
- Improves flexibility as the application grows.
- Encapsulates structural complexity.
Trade-offs
- Can introduce extra wrapper classes.
- Choose the pattern only when the complexity is real.
When should you use it?
- Simplifying a checkout workflow
- Hiding a library subsystem
- Providing a stable application API
Key takeawayProvide one simple entry point to a complex subsystem. Start with the smallest structure that solves the coupling or composition problem.