Question

I have the following:

class A
{
    public function getDependencies()
    {
        //returns A.default.css, A.default.js, A.tablet.css, A.tablet.js, etc,
        //depending on what files exist and what the user's device is.
    }
}

In class B, which extends A, if I call getDependencies I will get things like: B.default.css, B.default.js and so on.

What I want to do now is include the results of A as well, without having to override getDependencies() in B. In fact, I’m not even sure if overriding would work, at all. Is this possible?

This is for dynamic CSS/JS loading for templates, and eventually compilation for production as well.

EDIT= I should point out that what getDependencies returns is dynamically generated, and not a set of stored values.

EDIT2= The idea I have is that just inheriting from A will provide the behavior. I probably need some kind of recursion that goes through the hierarchy tree, starting from B, to B’s parent, and all the way up to A, without any method overriding happening along the way.

Answer 1

Use parent::getDependencies(), e.g.:

class B
{
  public function getDependencies()
  {
    $deps = array('B.style.js' 'B.default.js', 'B.tables.js' /*, ... */);
    // merge the dependencies of A and B
    return array_merge($deps, parent::getDependencies());
  }
}

You can also try this code which uses ReflectionClass in order to iterate over all parents:

<?php

class A
{
  protected static $deps = array('A.default.js', 'A.tablet.js');
  public function getDependencies($class)
  {
    $deps = array();

    $parent = new ReflectionClass($this);

    do 
    {
      // ReflectionClass::getStaticPropertyValue() always throws ReflectionException with
      // message "Class [class] does not have a property named deps"
      // So I'm using ReflectionClass::getStaticProperties()

      $staticProps = $parent->getStaticProperties();
      $deps = array_merge($deps, $staticProps['deps']);
    }
    while ($parent=$parent->getParentClass());

    return $deps;
  }
}
class B extends A
{
  protected static $deps = array('B.default.js');
}

class C extends B
{
  protected static $deps = array('C.default.js');
}

$obj = new C();
var_dump( $obj->getDependencies($obj) );

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