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PHP OOP

Notes taken at a conference - incomplete

• method and properties

  • private is accessible only within class
  • public is accessible anywhere
  • protected is available only to descendent

• constants:

  • const PI = 3.14159;
• static methods
  • analogous to class method in swift/objc
    • classname::method
    • Math::circularArea(5)

Inheritance

class Person {
    public $first;
    public $last;
}

class Employee extends Person {
    public $title;
}

• accessing parent

  • parent::[methodnamenobrackets]
• stopping Inheritance
  • final keyword
    • works on both classes and methods

Abstract classes

abstract class DataStore {
    //These methods must be defined in the child class
    abstract public function save();
    abstract public function load($id);

}

• abstract contract

  • all abstract methods must be implemented
  • method signatures must match exactly
• interfaces
  • interface defines method signatures that an implementing class must provide
  • similar to abstract methods but sharable between classes
  • no code, no properties, just an interoperability framework

interface Rateable {
    public function rate( int $stars, $user);
    public function getRating();
}

• interface implementation

class StatusUpdate implements Rateable, Searchable {
    protected $ratings[];

    public function rate(int $stars, $user) {
        $this->ratings[$user] = $stars;
    }

    public function search($query) {
        // search stuff
    }
}

Traits

trait Counter {
    protected $counter;

    public function increment() {
        $counter ++;
    }

    public funciton getCounter() {
        return $counter;
    }
}

class MyCounter {
    use Counter;
}

$counter = new MyCounter();
$counter->increment();
echo $counter->getCount(); //1

Late Static Binding

• insert stuff here

Namespaces

<?php
namespace WorkLibrary;

class Database {
    //stuff
}

.....

<?php
namespace MyLibrary;

class Database {
    // stuff
}

• usage:

  • $db = MyLibrary\Database::connect();
  • use MyLibrary\Database;
    • $db = Database::connect();
  • use MyLibrary\Database as MyD;;
    • $model = new MyD();
  • using built in classes with toplevel
    • $images = new \DateTime();
• backslash \ allows for sub-namespaces as a separator

Magic Methods

• magic methods start with __
• allow for code that is not directly called to run
• often have counterparts:
  • __construct() and __destruct()
  • __set() and __get()

this document last modified: May 12 2018 17:45

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