How to Create a class in PHP

Limited Time Offer!

For Less Than the Cost of a Starbucks Coffee, Access All DevOpsSchool Videos on YouTube Unlimitedly.
Master DevOps, SRE, DevSecOps Skills!

Enroll Now

Interface:

An interface is like a class with nothing but abstract methods. All methods of an interface must be public. It is also possible to declare a constructor in an interface. It’s possible for interface to have constants(can not be overridden by a class/interface that inherits them). interface keyword is used to create an interface in php.

  • Interface don’t have instance variables.
  • All methods of an interface is abstract.
  • All methods of an interface are automatically (by default) public.
  • We can not use the private and protected specifiers when declaring member of an interface.
  • We can not create object of interface.
  • More than one interface can be implemented in a single class.
  • A class implements an interface using implements keyword.
  • If a class is implementing an interface it has to define all the methods given in that interface.
  • If a class does not implement all the methods declared in the interface, the class must be declared abstract.
  • The method signature for the method in the class must match the method signature as it appears in the interface.
  • Any class can use an interface’s constants from the name of the interface like Test::roll.
  • Classes that implement an interface can treat the constants as they were inherited.
  • An interface can extend (inherit) an interface.
  • One interface can inherit another interface using extends keywords.
  • An Interface can not extends classes.

Defining Interface:

Syntax: - 
interface interface_name 
{
	const properties;
	Method;
} 

Ex: - 
interface Father  
{
	const a;
	public function disp( );
} 

Extending Interface:

  • An interface can extend (inherit) an interface.
  • One interface can inherit another interface using extends keywords.
  • An Interface can not extends classes.

One Interface extending one Interface:

interface interface_name1
{
	const properties;
	Methods;
}

interface interface_name extends interface_name1
{
	const properties;
	Method;
}

One interface can extend more than one interface:

interface Father
{

}

interface Mother
{

}

interface Son extends Father, Mother
{

}

Implementing Class:

  • More than one interface can be implemented in a single class.
  • A class implements an interface using implements keyword.
  • If a class is implementing an interface it has to define all the methods given in that interface.
  • If a class does not implement all the methods declared in the interface, the class must be declared abstract.
  • The method signature for the method in the class must match the method signature as it appears in the interface.
  • Any class can use an interface’s constants from the name of the interface like Test::roll.
  • Classes that implement an interface can treat the constants as they were inherited.

one interface can be implemented in a single class:

interface interface_name
{
	const properties;
	Methods;
}

class class_name implements interface_name
{
	Properties;
	Methods;
}

More than one interface can be implemented in a single class:

{

}

interface Mother
{

}

class Son implements Father, Mother
{

}

Abstract Class:

A class that is declared with abstract keyword, is known as abstract class in PHP. It can have abstract and non-abstract methods. It needs to be extended and its method implemented. objects of an abstract class cannot be created.

abstract class Test
{

}

Abstract Method:

A method that is declared as abstract and does not have implementation is known as abstract method

abstract function disp( ); //no body and abstract

abstract class Father 
{
	abstract function disp ( );
}

Class Son extends Father
{
	public function disp ( )
	{
		echo “Abstract defined”;
	}
}

Rules:

  • We cannot use abstract classes to instantiate objects directly.
  • objects of an abstract class cannot be created.
  • The abstract methods of an abstract class must be defined in its subclass.
  • If there is any abstract method in a class, that class must be abstract.
  • A class can be abstract without having abstract method.
  • It is not necessary to declare all methods abstract in a abstract class.
  • We cannot declare abstract constructors or abstract static methods.
  • If you are extending any abstract class that have abstract method, you must either provide the implementation of the method or make this class abstract.

Difference between interface and abstract class:

  • An abstract class can have only abstract methods or only non-abstract methods or both, but All methods of an interface are abstract by default.
  • An abstract class can declare properties/methods with access specifier, but interface can declare only constant properties and methods are by default abstract and public.
  • A class can inherit only one abstract class and multiple inheritance is not possible for abstract class but A class can implement more than one interface and can achieve multiple inheritance.
  • If a class contains even a single abstract method that class must be declared as abstract.
  • In an abstract class, you can defined as well as It’s body methods but in the interface you can only define your methods.
Subscribe
Notify of
guest

This site uses Akismet to reduce spam. Learn how your comment data is processed.

0 Comments
Oldest
Newest Most Voted
Inline Feedbacks
View all comments
0
Would love your thoughts, please comment.x
()
x