Consistent implementation of PHP class constants (arrays not allowed)

Question

I'm currently writing a class:

final class MyTestClass {
  const URL = 'http://www.example.org';
  private static $MY_ARRAY = array('...');

  // since this is not allowed
  // const MY_ARRAY = array('...');
}

So my question is whether I should make URL a private static variable, too? These values are constant and are only used in the class itself.

Answer 1

See PHP Constants Containing Arrays? . I think both are valid and also your current approach is fine. It's only important that you stick with one solution in your whole project.

Personally I think I would stay with your current solution.

Answer 2

I'm not quite sure that this question is on topic, however:

You have to understand what each variable definition is and what it means for the accesibility of that variable.

Say your class definition is as follows:

class MyTestClass {
  const URL = 'http://www.example.org';
  private static $MY_ARRAY = array('...');
}

And in the future you write another class that extends that class and it wants to update URL as below:

class SomeOtherClass extends MyTestClass {
  public __construct(){
    $this->URL = "http://www.someothersite.com";
  }
}

Now, if you never want URL to change, then that's fine. A better way to write MyTestClass however, would be:

class MyTestClass {
  private $URL = 'http://www.example.org';
  private $myArray = array();
}

Again however, if some class extends it, they won't be able to access the $URL var. Also, stay away from static.