PHP Tutorials - Herong's Tutorial Examples - v5.17, by Herong Yang
What Is a Trait
This section describes what is a trait - A trait is a pseudo class that defines a set of properties and operations. A trait can not be instantiated to create new objects. It can only be 'used' by one or more classes for the purpose of code sharing.
What Is a Trait? A trait is a pseudo class that defines a set of properties and operations. A trait can not be instantiated to create new objects. It can only be "used" by one or more classes for the purpose of code sharing.
In PHP, a trait is declared with the "trait" statement block. classes can share the code defined in a trait with the "use" statement. For example, the following tutorial example provides two traits "MySize" and "MyType" and one class "MyImage" that uses both traits.
<?php /* MyImage.php #- Copyright 2015 (c) HerongYang.com. All Rights Reserved. */ trait MySize { protected $width; protected $height; public function showSize() { echo " Size: " . $this->width .", ". $this->height ."\n"; } } trait MyType { public $type; public function showType() { echo " Type: " . $this->type ."\n"; } } class MyImage { use MySize; use MyType; protected $image; public function __construct($w,$h,$t) { $this->width = $w; $this->height = $h; $this->type = $t; $this->image = imagecreatetruecolor($this->width,$this->height); } public function showImage() { ob_start(); imagepng($this->image); $buffer = ob_get_contents(); ob_end_clean(); echo " Image: " . base64_encode($buffer) ."\n"; } } $object = new MyImage(8,8,"JPEG"); echo "MyImage object: \n"; $object->showSize(); $object->showType(); $object->showImage(); ?>
If you run the above tutorial example, you will get something like this:
herong> \php\php MyImage.php MyImage object: Size: 8, 8 Type: JPEG Image: iVBORw0KGgoAAAANSUhEUgAAAAgAAAAICAIAAABLbSncAAAA DElEQVQImWNgGB4AAADIAAH4XVuUAAAAAElFTkSuQmCC
Note that this tutorial requires cairo graphics library from cairographics.org.
Table of Contents
Introduction and Installation of PHP
PHP Data Types and Data Literals
Variables, References, and Constants
Expressions, Operations and Type Conversions
Conditional Statements - "if" and "switch"
Loop Statements - "while", "for", and "do ... while"
Function Declaration, Arguments, and Return Values
Interface with Operating System
►Introduction of Class and Object
What Is a Superclass and a Subclass
What Is an Overloaded Property
What Is Object Property Iteration
Updating Variables Who Share an Object
Passing Objects as Function Arguments
Integrating PHP with Apache Web Server
Retrieving Information from HTTP Requests
Creating and Managing Sessions in PHP Scripts
Sending and Receiving Cookies in PHP Scripts
Controlling HTTP Response Header Lines in PHP Scripts
MySQL Server Connection and Access Functions
Functions to Manage Directories, Files and Images
SOAP Extension Function and Calling Web Services
SOAP Server Functions and Examples
Localization Overview of Web Applications
Using Non-ASCII Characters in HTML Documents
Using Non-ASCII Characters as PHP Script String Literals
Receiving Non-ASCII Characters from Input Forms
"mbstring" Extension and Non-ASCII Encoding Management
Managing Non-ASCII Character Strings with MySQL Servers
Parsing and Managing HTML Documents
Configuring and Sending Out Emails
Managing PHP Engine and Modules on macOS