一个班级有多少静态方法太多？

Question

UPDATE: Rephrasing the question to ask, 'are there too many' static methods (I realize that right now there are only 4 but I originally started with 2) in this class structure? If so, any suggestions on how to refactor these classes to use some sort of Finder class so that I can remove the static functions from the Model classes?

I have the following abstract class:

abstract class LP_Model_Abstract
{
protected static $_collectionClass = 'LP_Model_Collection';

protected $_row = null;

protected $_data = array();

public function __construct($row = null)
{
    $this->_row = $row;
}

public function __get($key)
{
    if(method_exists($this, '_get' . ucfirst($key)))
    {
        $method = '_get' . ucfirst($key);
        return $this->$method();            
    }
    elseif(isset($this->_row->$key))
    {
        return $this->_row->$key;
    }
    else
    {
        foreach($this->_data as $gateway)
        {
            if(isset($gateway->$key))
            {
                return $gateway->$key;
            }
        }
    }   
}

public function __set($key, $val)
{
    if(method_exists($this, '_set' . ucfirst($key)))
    {
        $method = '_set' . ucfirst($key);
        return $this->$method($val);            
    }
    elseif(isset($this->_row->$key))
    {
        $this->_row->$key = $val;
        return $this->_row->$key;
    }
    else
    {
        foreach($this->_data as $gateway)
        {
            if(isset($this->_data[$gateway]->$key))
            {
                $this->_data[$gateway]->$key = $val;
                return $this->_data[$gateway]->$key;
            }
        }
    }
}

public function __isset($key)
{
    return isset($this->_row->$key);
}

public function save()
{
    $this->_row->save();
}

abstract public static function get($params);
abstract public static function getCollection($params = null);
abstract public static function create($params);

}

And then this class which provides additional functionality for class table inheritance schemes (where type is important in determining additional functionality in a factory fashion):

abstract class LP_Model_Factory_Abstract extends LP_Model_Abstract
{
    protected static $_collectionClass = 'LP_Model_Collection_Factory';

    abstract public static function factory($row);
}

These ultimately result in the following type of class declaration:

class Model_Artifact extends LP_Model_Factory_Abstract
{
    protected static $_artifactGateway = 'Model_Table_Artifact';

    public static function create($params)
    {

    }

    public static function get($params) 
    {
        $gateway = new self::$_artifactGateway();

        $row = $gateway->fetchArtifact($params);

        return self::factory($row);        
    }

    public static function getCollection($params = null) 
    {
        $gateway = new self::$_artifactGateway();

        $rowset = $gateway->fetchArtifacts($params);

        $data = array(
            'data' => $rowset,
            'modelClass' => __CLASS__
        );

        return new self::$_collectionClass($data);
    }

    public static function factory($row)
    {
        $class = 'Model_Artifact_' . $row->fileType;
    }
}

When do you know that you have too many static methods in a class? And how would you refactor the existing design so that the static methods are perhaps encapsulated in some sort of Finder class?

Answer 1

Personally I find that any number of static methods are a sign of trouble. If your class has instance methods and static methods, then most likely you could split the class into two separate entities and change the static methods to instance methods.

Think of a class as a special kind of object, with the distinctive property that it is global by nature. Since it's a global variable, it implies a very strong level of coupling, so you would want to reduce any references to it. Static members will need to be referred, meaning that your code will get a strong level of coupling to the class.