PHP数组，只包含特定类的对象

Question

I have a class called Rule and I'm about to create a RuleContainer class that's actually an array of Rule objects.

I wonder if there is an alternative of creating a new class. Is there any (modern) way to approach this problem? That is, something like using SPL to define an array that only allows adding objects of a specific class.

If not, which interface should I implement in my RuleContainer class?

Answer 1

The most suitable class for your task would be SplObjectStorage, but it doesn't allow for class typehint.

I think, you could do as follow:

class RuleContainer extends SplObjectStorage
{
    function attach(Rule $rule)
    {
         parent::attach($rule);
    }

    function detach(Rule $rule)
    {
         parent::detach($rule);
    }
}

and so on. You can read for SplObjectStorage interface on php.net and decide, what will you use and what needs overriding.