L’Adaptateur est un patron de conception structurel qui permet à des objets incompatibles de collaborer.
L’adaptateur fait office d’emballeur entre les deux objets. Il récupère les appels à un objet et les met dans un format et une interface reconnaissables par le second objet.
Exemples d’utilisation : L’adaptateur est très répandu en Python. On le retrouve souvent dans des systèmes basés sur du code hérité, dans lesquels l’adaptateur fait fonctionner du code hérité avec des classes modernes.
Identification : L’adaptateur peut être identifié grâce à son constructeur qui prend une instance d’un type abstrait différent ou d’une interface différente. Lorsque l’une des méthodes de l’adaptateur est appelée, il traduit les paramètres dans un format approprié et redirige l’appel vers une ou plusieurs méthodes de l’objet emballé.
Exemple conceptuel (héritage)
Dans cet exemple, nous allons voir la structure du patron de conception Adaptateur. Nous allons répondre aux questions suivantes :
Que contiennent les classes ?
Quel rôle jouent-elles ?
Comment les éléments du patron sont-ils reliés ?
main.py: Exemple conceptuel
class Target:
"""
The Target defines the domain-specific interface used by the client code.
"""
def request(self) -> str:
return "Target: The default target's behavior."
class Adaptee:
"""
The Adaptee contains some useful behavior, but its interface is incompatible
with the existing client code. The Adaptee needs some adaptation before the
client code can use it.
"""
def specific_request(self) -> str:
return ".eetpadA eht fo roivaheb laicepS"
class Adapter(Target, Adaptee):
"""
The Adapter makes the Adaptee's interface compatible with the Target's
interface via multiple inheritance.
"""
def request(self) -> str:
return f"Adapter: (TRANSLATED) {self.specific_request()[::-1]}"
def client_code(target: "Target") -> None:
"""
The client code supports all classes that follow the Target interface.
"""
print(target.request(), end="")
if __name__ == "__main__":
print("Client: I can work just fine with the Target objects:")
target = Target()
client_code(target)
print("\n")
adaptee = Adaptee()
print("Client: The Adaptee class has a weird interface. "
"See, I don't understand it:")
print(f"Adaptee: {adaptee.specific_request()}", end="\n\n")
print("Client: But I can work with it via the Adapter:")
adapter = Adapter()
client_code(adapter)
Output.txt: Résultat de l’exécution
Client: I can work just fine with the Target objects:
Target: The default target's behavior.
Client: The Adaptee class has a weird interface. See, I don't understand it:
Adaptee: .eetpadA eht fo roivaheb laicepS
Client: But I can work with it via the Adapter:
Adapter: (TRANSLATED) Special behavior of the Adaptee.
Exemple conceptuel (composition de l'objet)
This example illustrates the structure of the Adapter design pattern. It focuses on answering these questions:
What classes does it consist of?
What roles do these classes play?
In what way the elements of the pattern are related?
main.py: Exemple conceptuel
class Target:
"""
The Target defines the domain-specific interface used by the client code.
"""
def request(self) -> str:
return "Target: The default target's behavior."
class Adaptee:
"""
The Adaptee contains some useful behavior, but its interface is incompatible
with the existing client code. The Adaptee needs some adaptation before the
client code can use it.
"""
def specific_request(self) -> str:
return ".eetpadA eht fo roivaheb laicepS"
class Adapter(Target):
"""
The Adapter makes the Adaptee's interface compatible with the Target's
interface via composition.
"""
def __init__(self, adaptee: Adaptee) -> None:
self.adaptee = adaptee
def request(self) -> str:
return f"Adapter: (TRANSLATED) {self.adaptee.specific_request()[::-1]}"
def client_code(target: Target) -> None:
"""
The client code supports all classes that follow the Target interface.
"""
print(target.request(), end="")
if __name__ == "__main__":
print("Client: I can work just fine with the Target objects:")
target = Target()
client_code(target)
print("\n")
adaptee = Adaptee()
print("Client: The Adaptee class has a weird interface. "
"See, I don't understand it:")
print(f"Adaptee: {adaptee.specific_request()}", end="\n\n")
print("Client: But I can work with it via the Adapter:")
adapter = Adapter(adaptee)
client_code(adapter)
Output.txt: Résultat de l’exécution
Client: I can work just fine with the Target objects:
Target: The default target's behavior.
Client: The Adaptee class has a weird interface. See, I don't understand it:
Adaptee: .eetpadA eht fo roivaheb laicepS
Client: But I can work with it via the Adapter:
Adapter: (TRANSLATED) Special behavior of the Adaptee.
