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docs: update facade

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Ilkka Seppälä
2024-05-26 06:14:59 +03:00
parent d6bb988e42
commit 325b580ccc
1 changed files with 38 additions and 29 deletions
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facade/README.md
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@@ -3,9 +3,13 @@ title: Facade
category: Structural
language: en
tag:
- Abstraction
- API design
- Code simplification
- Decoupling
- Encapsulation
- Gang Of Four
- Interface
- Object composition
---
@@ -17,7 +21,7 @@ Provide a unified interface to a set of interfaces in a subsystem. Facade define
Real-world example
> How does a goldmine work? "Well, the miners go down there and dig gold!" you say. That is what you believe because you are using a simple interface that goldmine provides on the outside, internally it has to do a lot of stuff to make it happen. This simple interface to the complex subsystem is a facade.
> Imagine a home theater system with multiple components: a DVD player, projector, surround sound system, and lights. Each component has a complex interface with numerous functions and settings. To simplify the use of the home theater system, a remote control (the Facade) is provided. The remote control offers a unified interface with simple buttons like "Play Movie," "Stop," "Pause," and "Volume Up/Down," which internally communicate with the various components, managing their interactions. This makes the system easier to use without needing to understand the detailed operations of each component.
In plain words
@@ -29,7 +33,9 @@ Wikipedia says
**Programmatic Example**
Let's take our goldmine example from above. Here we have the dwarven mine worker hierarchy. First, there's a base class `DwarvenMineWorker`:
How does a goldmine work? "Well, the miners go down there and dig gold!" you say. That is what you believe because you are using a simple interface that goldmine provides on the outside, internally it has to do a lot of stuff to make it happen. This simple interface to the complex subsystem is a facade.
Here we have the dwarven mine worker hierarchy. First, there's a base class `DwarvenMineWorker`:
```java
@@ -161,35 +167,37 @@ public class DwarvenGoldmineFacade {
Now let's use the facade:
```java
var facade = new DwarvenGoldmineFacade();
facade.startNewDay();
facade.digOutGold();
facade.endDay();
public static void main(String[] args) {
var facade = new DwarvenGoldmineFacade();
facade.startNewDay();
facade.digOutGold();
facade.endDay();
}
```
Program output:
```java
// Dwarf gold digger wakes up.
// Dwarf gold digger goes to the mine.
// Dwarf cart operator wakes up.
// Dwarf cart operator goes to the mine.
// Dwarven tunnel digger wakes up.
// Dwarven tunnel digger goes to the mine.
// Dwarf gold digger digs for gold.
// Dwarf cart operator moves gold chunks out of the mine.
// Dwarven tunnel digger creates another promising tunnel.
// Dwarf gold digger goes home.
// Dwarf gold digger goes to sleep.
// Dwarf cart operator goes home.
// Dwarf cart operator goes to sleep.
// Dwarven tunnel digger goes home.
// Dwarven tunnel digger goes to sleep.
```
06:07:20.676 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf gold digger wakes up.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf gold digger goes to the mine.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf cart operator wakes up.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf cart operator goes to the mine.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarven tunnel digger wakes up.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarven tunnel digger goes to the mine.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenGoldDigger -- Dwarf gold digger digs for gold.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenCartOperator -- Dwarf cart operator moves gold chunks out of the mine.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenTunnelDigger -- Dwarven tunnel digger creates another promising tunnel.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf gold digger goes home.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf gold digger goes to sleep.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf cart operator goes home.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarf cart operator goes to sleep.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarven tunnel digger goes home.
06:07:20.678 [main] INFO com.iluwatar.facade.DwarvenMineWorker -- Dwarven tunnel digger goes to sleep.
```
## Class diagram
![alt text](./etc/facade.urm.png "Facade pattern class diagram")
![Facade](./etc/facade.urm.png "Facade pattern class diagram")
## Applicability
@@ -201,10 +209,10 @@ Use the Facade pattern when
## Tutorials
* [DigitalOcean](https://www.digitalocean.com/community/tutorials/facade-design-pattern-in-java)
* [Refactoring Guru](https://refactoring.guru/design-patterns/facade)
* [GeekforGeeks](https://www.geeksforgeeks.org/facade-design-pattern-introduction/)
* [Tutorialspoint](https://www.tutorialspoint.com/design_pattern/facade_pattern.htm)
* [Facade Design Pattern in Java (DigitalOcean)](https://www.digitalocean.com/community/tutorials/facade-design-pattern-in-java)
* [Facade (Refactoring Guru)](https://refactoring.guru/design-patterns/facade)
* [Facade Method Design Pattern (GeekforGeeks)](https://www.geeksforgeeks.org/facade-design-pattern-introduction/)
* [Design Patterns - Facade Pattern (TutorialsPoint)](https://www.tutorialspoint.com/design_pattern/facade_pattern.htm)
## Known Uses
@@ -225,10 +233,11 @@ Trade-offs:
## Related Patterns
* Often used with other design patterns like Singleton and Abstract Factory.
* Command pattern can use Facade to define an interface that simplifies methods invocation.
* [Adapter](https://java-design-patterns.com/patterns/adapter/): Facade provides a unified interface while Adapter makes two existing interfaces work together.
* [Mediator](https://java-design-patterns.com/patterns/mediator/): Facade defines a simpler interface to a subsystem while Mediator centralizes complex communications and control between objects.
## Credits
* [Design Patterns: Elements of Reusable Object-Oriented Software](https://amzn.to/3QbO7qN)
* [Effective Java](https://amzn.to/4cGk2Jz)
* [Head First Design Patterns: Building Extensible and Maintainable Object-Oriented Software](https://amzn.to/3UpTLrG)