Object Oriented PHP
In object-oriented programming, a class is a blueprint for creating objects (a particular data structure), providing initial values for state (member variables or attributes), and implementations of behavior (member functions or methods). The class is a blueprint that defines a nature of a future object.
Object Oriented PHP
Over 80% of websites are now written in PHP, making it more important than ever for web developers to master this programming language. Although the PHP basics are easy to learn, it is the knowledge of Object-oriented PHP that separates the professionals from the hobbyists.
When using Object-oriented programming, we organize the code in an efficient way, so it is easier to work with, develop and upgrade. Due to its many benefits, developers who master the craft of Object-oriented PHP are a hot commodity in the job market among companies and enterprises that have a need for advanced online applications.
PHPenthusiast is tailor-made for developers who are serious about mastering Object-oriented PHP. We not only provide easy-to-understand and concise tutorials, but also coding exercises to practice the newly acquired skills. By doing so, we make the learning process as fast and smooth as it can be.
PHP follows the organizing principles of functional, procedural, imperative, and object-oriented programming. You can use any of them or even a mixture of these programming paradigms. In this article, you will look into the OOPs methodology introduced in PHP. OOPs concepts in PHP can help the developers develop real-world applications that support reusability and are dynamic and complex in nature.
Object-Oriented Programming or simply OOPs is a programming approach or paradigm that gives its prime consideration to the data and its associated functions. It uses the concept of wrapping up the data as an object-entity having its associated properties, to provide higher security and less exposure to the data. As nothing is more important than the data itself, this approach is highly in use and widely accepted by programmers worldwide. The programming languages that do not support OOPs methodologies and their concepts are slowly getting deprecated, and the languages that are now being developed, support OOPs and are the extended version of object-oriented programming.
To relate programming with the real world, this methodology considers everything in the world as an entity or an object, and every object has some of its attributes or properties. So, the concept of the classes and objects can be applied to model an entire application. The overall development of an application in an object-oriented perspective can be summarized as:
The PHP programming language is based on the paradigm of Object-Oriented Programming (OOPs). Object-Oriented Programming is an umbrella under which the features of Object-Based programming resides. Meaning, it consists of all the characteristics of object-based programming and gets the better of its limitations by executing inheritance so that through programming, you can solve the problems based on real-life situations. Object-oriented programming was created to get better at the drawbacks of usual programming techniques. The OOPs concepts in PHP have been developed on some concepts that make it achieve its aim of getting the better of the drawbacks or deficiency of usual programming techniques.
When you define a class, with all its data members and member functions, then every instance or object of that class will occupy the memory equal to the memory allocated to the data members of that class. For eg: if a class has been allocated 10 bytes of memory for its data members, and if there are three objects of this class, namely obj1, obj2, and obj3, 10 bytes of memory will be allocated to each of the objects.
A module is a separate unit in itself. Hence you can execute a separate module as it is connected to other modules in some manner. All the modules act together as a single unit to achieve the aim of the program. In OOPs, classes and objects form the basic foundation of a system.
Class is one of the most critical OOPs Concepts in PHP. A class can have any number of instances or objects. All the objects of a class will have access to all the data members and member functions of that class. To create an object of a class in PHP, the new keyword is used.
Consider the same example discussed earlier. There is a subject, which can have a specialized field as its property. The following program defines a class named subject which has a constructor and a member function that prints the name of the specialized field of that subject. You can create different objects for the class subject.
Constructor is a type of a member function of the class in PHP. Constructors are a critical part of classes as they act as a blueprint to create objects of the class. Unlike other member functions, a constructor does not need to be called. It gets automatically called once you create the object.
Destructor is also a special member function of a class in PHP. The purpose of the destructor is exactly the opposite of the purpose of the constructor. The destructor gets called when you delete an object of the class from the memory. The destructor does not accept any kind of argument and does not return anything.
The static keyword is used to directly access without creating the objects. Methods that are recognized as static methods can be accessed directly. Static functions are only used in relation to classes rather than objects. These functions are only allowed to access the methods that are considered static methods. To achieve this feat, you need to use the static keyword.
In this article, you learned about OOPs Concepts in PHP. You saw PHP and its object-oriented concepts in depth. Then, you dived deep into the constructors, destructors, and keywords used in PHP. Finally, you explored in detail what PHP is, and its various aspects.
The fundamental idea behind an object-oriented language is to enclosea bundle of variables and functions into a single unit and keep both variables and functions safe from outside interference and misuse.Such a unit is called object which acts on data.The mechanism that binds together data and functions are called encapsulation. This feature makes it easy to reuse code in various projects. The functions declared in an objectprovides the way to access the data. The functions of an object are called methods and all the methods of an object have access to variables called properties.The following picture shows thecomponents of an object.
In object-oriented programming, a class is a construct or prototype from which objects are created. A class defines constituent members which enable class instances to have state and behavior. Data field members enable a class object to maintain state and methods enable a class object's behavior. The following picture shows the components of a class.
After an object is instantiated, you can access the property of a class using the object and -> operator. Any member declared with keyword "private" or "protected" cannot be accessed outside the method of the class.
After an object is instantiated, you can access the method of a class using the object and -> operator. In the following example customize_print() method will print a string with a specific font size and color within a html paragraph element with the help of php echo statement.
Note: PHP uses inheritance in it's object model and when you extend a class, the subclass inherits all of the public and protected methods from the parent class. When we will discuss the inheritance, you will get more information about protected properties and methods.
Like properties, constructors can call class methods or other functions. In the following example there is no need to call the method separately (after creating the object and passing the parameters, see the previous example) as it is already declared within the constructor. See the following example :
Many developers writing object-oriented applications create one PHP source file per class definition. One of the biggest annoyances is having to write a long list of needed includes at the beginning of each script (one for each class). Traditionally __autoload() function was used to automatically load classes. As of PHP 5.1.2 a new function spl_autoload_register() is introduced which provides a more flexible alternative for autoloading classes. For this reason, using __autoload() is discouraged and may be deprecated or removed in the future.
In the above example we are trying to create two objects, where class names 'class1' (save in /php/classes-objects/resource/class1.php) and 'class2' (save in /php/classes-objects/resource/class2.php). PHP passes this name as a string to spl_autoload_register(), which allows you to pick up the variable and use it to "include" the appropriate class/file.
Although PHP is still not as strong in its OOP feature set as other languages, object-oriented programming in PHP has a lot going for it. And while it is possible to have a good career without learning and using OOP, you should familiarize yourself with the concept. At the very least, being able to use both OOP and procedural programming allows you to better choose the right approach for each individual project.
The two most important terms for OOP are class and object. A class is a generalized definition of a thing. Think of classes as blueprints. An object is a specific implementation of that thing. Think of objects as the house built using the blueprint as a guide. To program using OOP, you design your classes and then implement them as objects in your programs when needed.
As for the technical negatives of OOP, use of objects can be less efficient than a procedural approach. The performance difference between using an object or not may be imperceptible in some cases, but you should be aware of this potential side effect. 041b061a72