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PHP Interface

An interface is a way of defining a contract for classes that implement that interface. It specifies a list of methods that should be implemented in the implementing class, without specifying any implementation details.

Syntax

The syntax for declaring an interface in PHP is as follows:

interface InterfaceName
{
    public function method1();
    public function method2();
    // more methods...
}

Example

Let's take a look at an example of an interface in PHP:

interface Vehicle
{
    public function start();
    public function stop();
    public function accelerate();
}

In this example, we have defined an interface called Vehicle, which defines three methods: start(), stop(), and accelerate().

Explanation

An interface in PHP is simply a contract. It defines a list of methods that a class that implements the interface must provide an implementation for. The purpose of an interface is to provide a common API for a group of related classes, allowing their behavior to be interchangeable.

An interface is declared using the interface keyword, followed by the name of the interface. The list of methods that the interface defines is then specified inside curly braces.

When a class implements an interface, it must provide an implementation for all of the methods defined in the interface. If it does not, it will result in a fatal error.

Use

Interfaces are particularly useful when you want to define a common API for a group of related classes. This allows you to write code that can work with any class that implements the interface, without having to know anything specific about the implementation details of the class.

Interfaces also enable you to create mock objects for testing. You can create a mock object that implements an interface, which can be used to test the behavior of other objects that depend on the interface.

Important Points

  • Interfaces should only define method signatures, not any implementation details.
  • A class can implement multiple interfaces.
  • Interfaces can be extended, just like classes.
  • Interfaces cannot be instantiated.

Summary

In PHP, an interface is a contract that specifies a list of methods that a class implementing the interface should provide an implementation for. Interfaces are useful for defining a common API for a group of related classes, and for creating mock objects for testing. They cannot be instantiated, and a class can implement multiple interfaces.

InheritanceOverloading
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