Calling static function from instance
I'm trying to call a static magic function (__callStatic
) from a member of its child class. Problem being, it goes to the non-static __call
instead.
<?php
ini_set("display_errors", true);
class a
{
function __call($method, $para开发者_如何学Goms)
{
echo "instance";
}
static function __callStatic($method, $params)
{
echo "static";
}
}
class b extends a
{
function foo()
{
echo static::bar();
// === echo self::bar();
// === echo a::bar();
// === echo b::bar();
}
}
$b = new b();
echo phpversion()."<br />";
$b->foo();
?>
Output:
5.3.6
instance
How can I make it display "static"?
If you remove the magic method '__call', your code will return 'static'.
According to http://php.net/manual/en/language.oop5.overloading.php "__callStatic() is triggered when invoking inaccessible methods in a static context".
What I think is happening in your code is that,
- You are calling static method from a non-static context.
- The method call is in non-static context, so PHP searches for the magic method '__call'.
- PHP triggers the magic method '_call' if it's exists. Or, if it's not exists it will call '_callStatic'.
Here is a possible solution:
class a
{
static function __callStatic($method, $params)
{
$methodList = array('staticMethod1', 'staticMethod2');
// check if the method name should be called statically
if (!in_array($method, $methodList)) {
return false;
}
echo "static";
return true;
}
function __call($method, $params)
{
$status = self::__callStatic($method, $params);
if ($status) {
return;
}
echo "instance";
}
}
class b extends a
{
function foo()
{
echo static::staticMethod1();
}
function foo2()
{
echo static::bar();
}
}
$b = new b();
echo phpversion()."<br />";
$b->foo();
$b->foo2();
In PHP there are the reserved words self
and parent
for accessing static methods from within a class and/or instantiated object. parent
refers to inherited methods from the parent class.
class b extends a
{
function foo()
{
echo parent::bar();
}
}
EDIT: Uhm, that doesn't do the trick… (using PHP 5.3.5)
$b = new b();
$b->foo(); // displays: instance
a::bar(); // displays: static
2nd EDIT: Ha, it works only, if you omit the __call()
-method in class a
.
class a
{
static function __callStatic($method, $params)
{
echo "static";
}
// function __call($method, $params)
// {
// echo "instance";
// }
}
class b extends a
{
function foo()
{
echo parent::bar();
}
}
$b = new b();
$b->foo(); // displays: static
a::bar(); // displays: static
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