Base Class

The Solar_Base class is a lightweight base class from which all other Solar classes descend (not including exceptions, which descend from the Solar_Exception class). This base class provides:

• A standard __construct() method that reads from the config file, then combines the instantiation-time constructor parameters with the default config values for the class.

• A $_config property to collect configuration values for the class and its parents.

• An _exception() method for finding and returning exceptions with localized message text.

• A locale() method for finding and returning localized text strings.

• An apiVersion() method for finding the API version of the class.

Extending the Base Class

When you extend from the Solar_Base class, make sure the only constructor parameter is $config = null (this is how it receives instantiation-time configuration values) and that it calls the parent constructor at some point (with the $config parameter passed up the chain).

For example:

<?php
class Solar_Example extends Solar_Base {

    // default config values
    protected $_Solar_Example = array(
        'opt_1' => 'foo',
        'opt_2' => 'bar',
        'opt_3' => 'baz'
    );

    // constructor
    public function __construct($config = null)
    {
        // pre-parent setup code
        // ...

        // parent construction
        parent::__construct($config);

        // post-parent setup
        // ...
    }
}
?>

Config File Settings

Now, if your config file has an 'Solar_Example' group in it, those values will override any of the default values set by your class definition. Say your config file looks something like this:

<?php
$config = array();
// ...
$config['Solar_Example']['opt_3'] = 'dib';
// ...
return $config;
?>

When you instantiate the Solar_Example object, the config file values will override the default values, leaving all others in place:

<?php
$example = Solar::factory('Solar_Example');
/*
  The values of $example->_config are now:

  'opt_1' => 'foo'
  'opt_2' => 'bar'
  'opt_3' => 'dib' // from the config file
*/
?>

Instantiation Settings

Finally, if you specify a configuration array as the second parameter of Solar::factory(), those values override both the default values of the class definition and the Solar.config.php values.

<?php
$config = array('opt_2' => 'gir');
$example = Solar::factory('Solar_Example', $config);
/*
  The values of $example->_config are now:

  'opt_1' => 'foo' // as defined by the class
  'opt_2' => 'gir' // from the Solar::factory() instantiation config
  'opt_3' => 'dib' // from the config file
*/
?>

Order of Precedence

All of this is to say that the order of precedence for config values looks like this:

• The values start as defined by the class,

• And are overwritten by any config file values,

• And are again overwritten by values set at instantiation time

Note that values not changed remain the same, so if you leave one out, it's not overwritten to be null.