What exactly is an interface? Is it something that you should worry about or even care about?
An interface is a way of connecting two programs together. In other words, it allows them to communicate with each other.
For example, you might want to connect an application to a database.
This would allow the application to access information stored in the database.
Interfaces are often created using object-oriented programming (OOP).
They are also called protocols because they define the rules between two programs.
Interfaces are usually written in C++, Java, PHP, Python, Ruby, etc.
What Is An Abstract Class, And What Does It Do?
Abstract classes are used when you need to create a base class for all your objects.
The base class will contain common properties like name, age, address, etc.
You can then inherit from this class to create more specific classes.
For example, if you have a class named Person, you could make another class called Student which inherits from Person.
A student has different attributes than a person such as a GPA, major, etc.
What Are Interfaces, And How Do They Work?
Interfaces are similar to abstract classes in that they define the rules between different types of objects.
However, instead of creating a base class, they are used to create a protocol between two objects. An interface is a contract between two objects.
It defines the methods that one object must implement and the data that the other object expects.
A good example of an interface is the IHttpRequest interface.
This interface defines the HTTP request method. It specifies that the client must send a GET request and expect a 200 response.
If the server receives anything else, it must return an error message.
PHP allows you to declare interfaces. An interface specifies what methods an object must provide.
Polymorphism allows you to use objects that do not necessarily share the exact same implementation.
What Exactly Is An Interface In PHP?
An interface is a contract that any class fulfilling the contract must follow.
This means that if you implement a certain interface, you must behave exactly as defined by this contract.
You should expect your class to respond to certain calls, return specific values, etc.
Vocalizing is a simple task. Given a message, vocalizing returns the sound as a string.
To create something of that type (implementing an interface), we need to have an existing implementation available.
Classes can do this by implementing interfaces. Let’s say we have such a function: This function can be called with anything that implements Vocalizer.
How Do We Use Interfaces?
Interfaces are used to create a communication channel between two objects. Imagine that you have a program that needs to talk to a database.
Instead of writing code that directly connects to the database, you could write a separate program that implements the IConnection interface.
The first program would be the connection manager. It would know how to connect to the database and how to read and write information.
The second program would be the actual application. It would call the methods on the ConnectionManager to perform its functions.
In this case, the Connection Manager doesn’t actually store any information. It simply acts as a bridge between the application and the database.
To implement an interface, a Class must use the implements’ keyword.
A Class that implements an interface must implement all the Interface’s Methods.
In a nutshell, interfaces give you a way to provide features by using methods instead of extending classes.
This can be really helpful for adapting existing classes to new situations.
As an example, let’s assume we had a Bird class that didn’t already implement Vocalizer, and we wanted to add similar behavior via a method tweet.
We could do one of these two things to make this Bird a Vocalizer at the moment, while still keeping all existing functionality.
We could either update the class to directly extend the Vocalizer interface, or we could change the method to use a call to the superclass’ implementation of the same method.
We should use an interface to make sure that our code works correctly regardless of what concrete class is used.
We should also be careful about using inheritance when there is a better alternative.
Why Do We Need Interfaces?
When programming, it’s important to remember that every piece of software has some sort of purpose.
When you design a program, you should consider the end goal.
You may not always think about why you’re designing a certain feature, but there is probably a reason behind it.
For example, imagine you’re designing a web-based shopping cart system.
You may not realize that you need to add a “checkout” button until you’ve designed everything else.
Once you have the checkout button, you’ll need to figure out how to process orders.
It’s much easier to design a program once you understand the overall goal.
Then you can start thinking about how each part fits into the larger picture.
The same concept applies to interfaces. There are many reasons why interfaces exist.
Some examples include:
- To prevent direct access to private members
- To provide a standard way to get or set member variables
- To allow multiple inheritances
- To specify what type of object is expected by a function
- To make sure that two objects meet a particular requirement
- To ensure that two objects communicate with each other without having to explicitly tell them how to communicate
- To force programmers to follow a specific coding style
- To enforce a common API (Application Programming Interface) across all programs
- To help developers reuse existing code
- To increase maintainability
- To reduce coupling among components
So, What Can Be Defined In A PHP Interface?
We can think about interfaces as being similar to Java’s abstract classes.
This means that you can create your own interfaces to help describe the behavior of a particular object or class.
You can also use them to help provide a common set of behaviors that other objects must adhere to in order to interact with each other.
For example, if you wanted to create a simple library of functions that could be used across a number of different applications, you might want to consider creating an interface that describes the expected behavior of those functions.
When you create an instance of this interface, you can then pass that instance into any function that expects an implementation of this interface.
Interfaces are a powerful tool for helping to define the structure of your code.
They can be especially useful when you’re trying to adapt a preexisting class to work with a new situation.
Interfaces can also help you avoid the problems associated with inheritance.
If you find yourself needing to inherit from a base class just because you don’t know how to solve a problem, you may benefit from looking at an interface first.