Behavioral Patterns help Programmers (Problem Solving)

Question: How do behavioral patterns help programmers solve problems?
Behavioral patterns stand as foundational pillars in the world of software engineering, offering time-tested solutions for facilitating object interactions. Their design provides programmers with efficient and elegant ways to handle intricate communication scenarios. Here's a technical breakdown of how these patterns empower programmers to tackle challenges:

1. Decoupling Interaction: Behavioral patterns ensure that interacting objects are decoupled, meaning they have minimal dependencies on each other. By reducing direct connections between objects, the system becomes more modular, allowing changes to one component without significant ripple effects.
2. Flexible Algorithms: Patterns such as the Strategy pattern allow algorithms to exist separately from the objects that use them. By defining a family of algorithms and making them interchangeable, programmers can select the most appropriate operation for a particular situation without altering the object that uses it.
3. Clearer Responsibility Allocation: Patterns like the Chain of Responsibility delegate tasks across a chain of objects. By ensuring that only one object handles a request, these patterns eliminate ambiguity about who is responsible for a particular operation, leading to cleaner and more maintainable code.
4. State Management: The State pattern allows an object to change its behavior when its internal state changes. This ensures that state-specific behavior is localized, reducing the complexity of the object and making it easier to manage.
5. Centralized Communication: The Mediator pattern centralizes external communications, meaning that instead of many objects talking to each other directly, they communicate via a mediator. This centralized approach simplifies maintenance and modifications, as changes often only need to be made in one place.
6. Event Notification: The Observer pattern provides a mechanism where an object can notify other objects of state changes without knowing who or what those objects are. This fosters a dynamic relationship between subjects and observers, facilitating real-time updates and reactions.
7. Iterative Access: The Iterator pattern furnishes a standardized way to traverse collections without exposing their internal structures. This ensures that collection details can change without affecting how they're accessed or traversed.
8. Command Encapsulation: The Command pattern encapsulates a request as an object, decoupling the sender and receiver. This not only offers a clearer structure but also allows for parameterization, queuing, and logging of requests.
9. Memory and Restoration: The Memento pattern captures an object's internal state, enabling restoration to that state later. This proves invaluable in functionalities like undo mechanisms.
10. Dynamic Behavior Change: The Visitor pattern lets new operations be added to existing classes without modifying them, promoting flexibility.

In essence, behavioral patterns act as blueprints, refined over decades of software engineering practice. They encapsulate best practices for object interactions, ensuring that systems are robust, maintainable, and scalable. Armed with these patterns, programmers can confidently address a spectrum of challenges, knowing they're building on a solid foundation.

Each behavioral pattern solves a different problem, but many share certain characteristics. Most behavioral patterns allow programmers or users to change the behavior of objects, classes or sub-systems by changing the parts that make up the system. This makes the system easier to understand by separating the essential parts from the variable parts. Furthermore, the interface generally remains the same even when the variable parts are swapped out.
Other beneficial effects of using behavioral patterns include:

1. Decoupling objects from the objects that send requests to them and that they send requests to
   
2. Allowing algorithms to be parameterized and selected dynamically
3. Queuing messages and executing them in sequence (particularly useful in a multithreaded environment)

UML offers the following five behavior diagrams, which can be used to represent the dynamic behavioral aspects of an application.

1. Use Case Diagrams
2. Sequence diagrams
3. Activity diagrams
4. Collaboration diagrams
5. Statechart diagram

1. Deal with the details of assigning responsibilities between different objects
2. Describe the communication mechanism between objects
3. Define the mechanism for choosing different algorithms by different objects at runtime

In this exercise, you will run some tests on the Vehicle classes you have already created.
Testing Interface - Exercise