The scenario is this
class a
{
public $val;
}
class b extends a
{
}
class c extends b
{
}
$one = new b();
$one->val = "a value";
$other = new c();
echo $other->val;
// wanted 'a value', got ''
So the result i need here is: "a value", but of course is blank.
What i need is that the 'a' class to always be used as an instance in 'b'. So whenever i use a class that extends the 'b', the parent 'a' class to be inhereted as an instance.
If you read the php manual on the static keyword it gives an example of exactly what you are trying to do. You can read about it here: http://www.php.net/manual/en/language.oop5.static.php
Here is the example code they use.
<?php
class Foo
{
public static $my_static = 'foo';
public function staticValue() {
return self::$my_static;
}
}
class Bar extends Foo
{
public function fooStatic() {
return parent::$my_static;
}
}
print Foo::$my_static . "\n";
$foo = new Foo();
print $foo->staticValue() . "\n";
print $foo->my_static . "\n"; // Undefined "Property" my_static
print $foo::$my_static . "\n";
$classname = 'Foo';
print $classname::$my_static . "\n"; // As of PHP 5.3.0
print Bar::$my_static . "\n";
$bar = new Bar();
print $bar->fooStatic() . "\n";
?>
Since $other = new c(); is actually creating a new instance, it is not possible.
but if you declare val as Static member, you will have the result that you want.
<?
class a
{
public static $val;
}
class b extends a
{
}
class c extends b
{
}
$one = new b();
a::$val = "a value";
echo c::$val;
Here is how to do it without Inheritance:
class A
{
public $foo;
}
class B {
public function __construct(A $a)
{
$this->a = $a;
}
}
class C {
public function __construct(A $a)
{
$this->a = $a;
}
}
$a = new A;
$b = new B($a);
$c = new C($a);
$b->a->val = 'one value';
echo $c->a->val;
If you dont like having to fetch $a first to get to val, you could assign by reference
class A
{
public $foo;
}
class B {
public function __construct(A $a)
{
$this->val = &$a->val;
}
}
class C {
public function __construct(A $a)
{
$this->val = &$a->val;
}
}
$a = new A;
$b = new B($a);
$c = new C($a);
$b->val = 'one value';
echo $c->val;
Though personally I find the first approach more maintainable and clear.
