The Mediator pattern is a design pattern in which an object, known as the mediator, centralizes the communication between other objects, called colleagues, without them having direct knowledge of one another.
The mediator pattern aims to reduce the complexity of the communication between the objects; the colleagues communicate indirectly, through the mediator object. As a result, the object is made easier to maintain and less coupled.
For example, consider a dialogue box displaying the temperature values of different cities. In this case, the object (the dialogue box) can act as a mediator between the colleagues (different temperature displays). Whenever a new city’s temperature is selected, the temperature display of that city needs to be updated in the dialogue box, the mediator thus handles this communication for the temperature displays, as they do not have to communicate independently about such updates.
In the mediator pattern, the mediator acts as an intermediary that manages the communication between the colleagues. It simplifies the communication between the objects by centralizing it, making it an efficient and effective form of communication.
Mediator pattern is a behavioral design pattern that is used to simplify the communication between a set of objects.
Multiple objects communicate with each other without having to know about each other by using a mediator object.
The mediator object acts as a coordinator between different objects in a system.
The mediator pattern improves the maintainability, scalability and testability of a system by reducing the dependencies between the different components.
The mediator pattern promotes loose coupling between objects and encourages good programming practices.
This pattern is appropriate when the objects in a system are complex and have many relationships with each other.
The mediator pattern can be implemented by creating a mediator class that encapsulates the interactions between objects, with methods for sending and receiving messages.
The mediator object can be implemented as a singleton, to ensure that there is only one instance of it in the system.
In a typical implementation, the mediator object passes messages between objects, and the objects can send and receive messages using the mediator as a conduit.
This pattern can be seen in many real-world scenarios, such as air traffic control systems or online marketplaces, where coordination between multiple components is necessary.
What is the Mediator Pattern and what problem does it solve?
Answer: The Mediator Pattern is a behavioral design pattern that allows for decoupling of objects by introducing a mediator to coordinate interactions between them. It solves the problem of complex communication between objects, reducing dependencies and making it easier to maintain and modify the system.
Can you explain the role of the Mediator in this pattern?
Answer: The Mediator acts as a central hub or communication channel between the objects that are participating in the interaction. It receives requests from objects and routes them to the appropriate receiver or chains them together to achieve the desired result.
How does Mediator differ from other design patterns like Observer or Command?
Answer: Mediator differs from Observer in that the former focuses on coordinating the communication between related objects while the latter focuses on minimizing coupling between sender and receiver by introducing an intermediary. Mediator differs from Command in that the former specifies the interactions between participating objects while the latter defines the request and its response in a single object.
What are the advantages and disadvantages of using Mediator Pattern?
Answer: The advantages of Mediator are that it provides a centralized control over the interactions, reducing coupling between objects and making the code easier to test, modify and maintain. The disadvantages are that it can lead to increased complexity and can result in less efficient code due to the additional overhead of coordination.
Can you provide an example of how Mediator Pattern can be applied in real-world scenarios?
Answer: Mediator can be applied in scenarios like airline traffic control systems, where a central mediator coordinates the communication between aircraft, airports and air traffic controllers. Similarly, in a complex e-commerce website, a mediator can be used to coordinate interactions between the shopping cart, payment gateway, shipping provider and customer support services.