Object interfaces in PHP

In PHP, an object interface defines a set of method signatures that a class must implement. It specifies what methods a class should have and what arguments and return types they should accept and return, but does not provide any implementation details.

When a class implements an interface, it agrees to implement all the methods defined in the interface. This allows for polymorphism, where objects of different classes can be treated as if they were the same type, as long as they implement the same interface.

Interfaces are useful for defining contracts between objects, ensuring that they can communicate and work together in a consistent manner. They also promote code reusability and make it easier to write testable and modular code.

To implement an interface, a class uses the implements keyword followed by the name of the interface. For example:

interface MyInterface { public function myMethod(); } class MyClass implements MyInterface { public function myMethod() { // implementation code here } }

This declares that MyClass implements the MyInterface interface, and must provide an implementation for the myMethod() method defined in the interface.