I've some code that creates ad instance with a dynamic class (i.e. from a variable):
$instance = new $myClass();
Since the constructor has different argument count depending on $myClass value, How do I pass a variable list of arguments to the new statement? Is it possible?
class Horse {
public function __construct( $a, $b, $c ) {
echo $a;
echo $b;
echo $c;
}
}
$myClass = "Horse";
$refl = new ReflectionClass($myClass);
$instance = $refl->newInstanceArgs( array(
"first", "second", "third"
));
//"firstsecondthird" is echoed
You can also inspect the constructor in the above code:
$constructorRefl = $refl->getMethod( "__construct");
print_r( $constructorRefl->getParameters() );
/*
Array
(
[0] => ReflectionParameter Object
(
[name] => a
)
[1] => ReflectionParameter Object
(
[name] => b
)
[2] => ReflectionParameter Object
(
[name] => c
)
)
*/
I don't know why but i don't like using the new operator in my code.
Here is a static function to create an instance of a class called statically.
class ClassName {
public static function init(){
return (new ReflectionClass(get_called_class()))->newInstanceArgs(func_get_args());
}
public static function initArray($array=[]){
return (new ReflectionClass(get_called_class()))->newInstanceArgs($array);
}
public function __construct($arg1, $arg2, $arg3){
///construction code
}
}
If you are using it inside a namespace you need to escape ReflectionClass like so: new \ReflectionClass...
Now you can call the init() method with a variable number of arguments and it will pass it on to the constructor and return an object for you.
Normal way using new
$obj = new ClassName('arg1', 'arg2', 'arg3');
echo $obj->method1()->method2();
Inline way using new
echo (new ClassName('arg1', 'arg2', 'arg3'))->method1()->method2();
Static call using init instead of new
echo ClassName::init('arg1', 'arg2', 'arg3')->method1()->method2();
Static call using initArray instead of new
echo ClassName::initArray(['arg1', 'arg2', 'arg3'])->method1()->method2();
The nice thing about the static methods is that you can run some pre construction operations in the init methods such as constructor argument validation.
The easiest route would be to use an array.
public function __construct($args = array())
{
foreach($array as $k => $v)
{
if(property_exists('myClass', $k)) // where myClass is your class name.
{
$this->{$k} = $v;
}
}
}
