Constructor Parameters

All __construct() methods in Solar have exactly one parameter: an associative array. That array is then populated into the protected $_config property used in all classes descended from the Solar base class.

Most classes in the PHP world use a sequential set of parameters for constructors; e.g., if you wanted to specify three pieces of information for a constructor, you would do something like this:

<?php
class Normal_Example {
    public $a = null;
    public $b = null;
    public $c = null;
    public function __construct($a, $b, $c)
    {
        $this->a = $a;
        $this->b = $b;
        $this->c = $c;
    }
}

$example = new Normal_Example('one', 'two', 'three')
?>

In comparison, Solar classes can be instantiated like this:

<?php
class Solar_Example extends Solar_Base {
    // note that the config property is named for the class
    // with an underscore prefix.  this lets us collect the
    // parent config defaults as well.
    protected $_Solar_Example = array(
        'a' => null,
        'b' => null,
        'c' => null,
    );
}

$config = array(
    'a' => 'one',
    'b' => 'two',
    'c' => 'three'
);

$example = new Solar_Example($config);
?>

Note: Usually Solar objects are instantiated via Solar::factory(), not via direct instantiation as above, but you get the idea.

Why do things this way? The idea is to make it easy to read data from a config file and automatically configure object instances.

In the Solar_Example class, the constructor parameter could easily be read from a configuration file and passed to the Solar_Example constructor, which is not so easy with the Normal_Example.