Book Image

PHP 7 Programming Cookbook

By : Doug Bierer
Book Image

PHP 7 Programming Cookbook

By: Doug Bierer

Overview of this book

PHP 7 comes with a myriad of new features and great tools to optimize your code and make your code perform faster than in previous versions. Most importantly, it allows you to maintain high traffic on your websites with low-cost hardware and servers through a multithreading web server. This book demonstrates intermediate to advanced PHP techniques with a focus on PHP 7. Each recipe is designed to solve practical, real-world problems faced by PHP developers like yourself every day. We also cover new ways of writing PHP code made possible only in version 7. In addition, we discuss backward-compatibility breaks and give you plenty of guidance on when and where PHP 5 code needs to be changed to produce the correct results when running under PHP 7. This book also incorporates the latest PHP 7.x features. By the end of the book, you will be equipped with the tools and skills required to deliver efficient applications for your websites and enterprises.
Table of Contents (22 chapters)
PHP 7 Programming Cookbook
Credits
Foreword
About the Author
About the Reviewers
www.PacktPub.com
Preface
Index

Extending classes


One of the primary reasons developers use OOP is because of its ability to re-use existing code, yet, at the same time, add or override functionality. In PHP, the keyword extends is used to establish a parent/child relationship between classes.

How to do it...

  1. In the child class, use the keyword extends to set up inheritance. In the example that follows, the Customer class extends the Base class. Any instance of Customer will inherit visible methods and properties, in this case, $id, getId() and setId():

    class Base
    {
      protected $id;
      public function getId()
      {
        return $this->id;
      }
      public function setId($id)
      {
        $this->id = $id;
      }
    }
    
    class Customer extends Base
    {
      protected $name;
      public function getName()
      {
        return $this->name;
      }
      public function setName($name)
      {
        $this->name = $name;
      }
    }
  2. You can force any developer using your class to define a method by marking it abstract. In this example, the Base class defines as abstract the...