Apex Interfaces

What is an Apex Interface?

In Apex, an interface is a collection of method signatures with no implementation. It defines a contract that classes must adhere to if they choose to implement the interface. This allows for a more flexible and reusable code structure, as different classes can implement the same interface in various ways.

Defining an Apex Interface

To define an interface in Apex, you use the interface keyword followed by the interface name. The methods are defined within the interface without any body.

Here's an example of a simple Apex interface:

Implementing an Apex Interface

When a class implements an interface, it must provide concrete implementations for all the methods declared in the interface. A class uses the implements keyword to indicate that it is implementing an interface.

Below is an example of how a class implements the Vehicle interface:

Benefits of Using Interfaces

Using interfaces in Apex provides several advantages:

• Abstraction: Interfaces allow you to define methods that must be implemented, promoting a clear separation of concerns.
• Reusability: Multiple classes can implement the same interface, allowing code reuse and consistency.
• Flexibility: Interfaces enable the implementation of different behaviors using the same method signature across various classes.

Interfaces vs. Abstract Classes

While both interfaces and abstract classes can be used to define abstract methods, they serve different purposes:

• Interfaces: Can only contain method signatures and final variables (constants). They provide a way to achieve polymorphism in Apex.
• Abstract Classes: Can have both abstract methods (without body) and concrete methods (with body). They are used when you want to share code among several closely related classes.