Abstract Classes & Methods
For Abstract Classes to exist there must be a parent class and a child class relationship. That means they can only exist in a situation a class inherits from another.
Abstract methods, in the child class have access to the both the public, protected and _construct properties.
Points to note:
- you have to declare an abstract method or class using the
abstractkeyword -For abstract methods they must have the same name in the child class as in the parent class. They must have the same number of arguments, however a child method can have additional arguments. - The child class method must be defined with the same or a less restricted access modifier.
Privatewont work.
Let us look at the following example:
<?php
abstract class Person{
public $name;
public function __construct($name){
$this->name= $name;
}
abstract function greet();
}
class Greeting extends Person{
public function greet() {
echo "Hello, {$this->name}";
}
}
$person1 = new Greeting("Samuel");
$person1->greet();
Let us look at this other example where abstract method has argument:
<?php
abstract class Person{
public $name;
public function __construct($name){
$this->name= $name;
}
abstract protected function greet($honor);
}
class Greeting extends Person{
public function greet($honor) {
echo "Hello, {$honor} {$this->name} ";
}
}
$person1 = new Greeting("Samuel");
$person1->greet("Hon");
Let us look at this other example where the child abstract method has optional argument:
<?php
abstract class Person{
public $name;
public function __construct($name){
$this->name= $name;
}
abstract protected function greet($honor);
}
class Greeting extends Person{
public function greet($honor,$salutation ="Welcome",$location ="Jamrock ") {
echo "Hello, {$honor} {$this->name} {$salutation} to {$location} ";
}
}
$person1 = new Greeting("Samuel");
$person1->greet("Professor");
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