php magic methods - oop
I will love to discuss into details about an interesting topic of PHP magic methods:
************************************************************************
---------------------- PHP MAGIC METHODS-----------------------------------------------------
***************************************************************************
-It is a special method in a class.
-It overrides the default action when the object performs the action.
-The names of magic method starts with a double underscore(__)
Some of examples are constructor __construct() and destructor __destruct() which are invoked when an object is created or deleted respectively.
Other examples :
__call() triggered when invoking an inaccessible instance method.
__callStatic triggered when invoking an inaccessible static method.
__get() Invoked when reading a value from a non existing or non accessible property
__set() Invoked when writing a value to a non accesible property
__isSet() Invoked when calling isSet() or empty() on non-existing or inaccesible property
__unset() Invoked when unSet() is called on non-existing or inaccesible method
__sleep() commits the pending data
__wakeUp() Invoked when the _unserialize() run to reconstruct any resource that an object may have
__serialize() calls _serialize() if its available,then construct to return an associative of key/values pairs that represent the serialized form of the object
__toString() Invoked when an object of a class is treated as a string
__invoke() Invoked when an object is invoked as a function
__set_state() Called for a class exported by var_export()
__clone() called when the cloning is complete
__debugInfo() called by var_dump() when dumping an object to get the properties that should be shown
-------->I WILL FOCUS ONLY ON __get() and __set() METHODS
PHP _SET METHOD
What happens when you write to a non-existing or inaccessible property in php??
->php calls the set method automatically
here is the syntax
public __set ( string $name , mixed $value ) : void
set method accepts the name and value you write to:
here is a detailed example:
<?php
class HtmlElement
{
private $attributes = [];
private $tag;
public function __construct($tag)
{
$this->tag = $tag;
}
public function __set($name, $value)
{
$this->attributes[$name] = $value;
}
public function html($innerHTML = '')
{
$html = "<{$this->tag}";
foreach ($this->attributes as $key => $value) {
$html .= ' ' . $key . '="' . $value . '"';
}
$html .= '>';
$html .= $innerHTML;
$html .= "</$this->tag>";
return $html;
}
}
EXPLAINING THE CODE:
- first define the HTMLElement class that has only one property $attributes.It will hold all the attribute of the html element.
- Initialize a constructor with a tag name.Tag name can be anything like div.
- Implement __set() method that add any property to the $attribute array
- Define HTMLElement to return the HTML representation of the element
Using the HTMLElement class above to create a new div element
<?php
require 'HTMLElement.php';
$div = new HtmlElement('div');
$div->id = 'page';
$div->class = 'light';
echo $div->html('Hello');
Output
<div id="page" class="light">Hello</div>
Attempting to write to not existing property
$div->id = 'page';
$div->class = 'light';
php calls the __set() method implicitly to add this methods to the $attribute property
PHP __GET() METHOD:
when you try to access the property that does not exist or inaccessible property like private or protected
php automatically calls the __get() method
-It only accepts one argument which is the name of property that you want to access.
public __get ( string $name ) : mixed
the following adds the __get method to HTMLElements class
<?php
class HtmlElement
{
private $attributes = [];
private $tag;
public function __construct($tag)
{
$this->tag = $tag;
}
public function __set($name, $value)
{
$this->attributes[$name] = $value;
}
public function __get($name)
{
if (array_key_exists($name, $this->attributes)) {
return $this->attributes[$name];
}
}
public function html($innerHTML = '')
{
$html = "<{$this->tag}";
foreach ($this->attributes as $key => $value) {
$html .= ' ' . $key . '="' . $value . '"';
}
$html .= '>';
$html .= $innerHTML;
$html .= "</$this->tag>";
return $html;
}
}
The __get() methods checks whether the property exists in the $attribute before returning the results
The following creates a new article element ,sets the id and class attributes then shows the value of this attributes
<?php
require 'HTMLElement.php';
$article = new HtmlElement('article');
$article->id = 'main';
$article->class = 'light';
// show the attributes
echo $article->class; // light
echo $article->id; // main
😝😝😝😝😝😝in conclusion
1) php calls the __get() method automatically when you access a non existing or innaccesible property
2)php calls the __set() method when you assign a value a value to a non existing or innaccesible property
with your love all💖💕💕💕💕kamau waweru---------->lets make the future and advance technology with php
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