.. _classes-scalarorobjectproperty:

.. _scalar-or-object-property:

Scalar Or Object Property
+++++++++++++++++++++++++

  Property shouldn't use both object and scalar syntaxes. When a property may be an object, it is recommended to implement the Null Object pattern : instead of checking if the property is scalar, make it always object.

.. code-block:: php
   
   <?php
   
   class x {
       public $display = 'echo';
       
       function foo($string) {
           if (is_string($this->display)) {
               echo $this->string;
           } elseif ($this->display instanceof myDisplayInterface) {
               $display->display();
           } else {
               print "Error when displaying\n";
           }
       }
   }
   
   interface myDisplayInterface {
       public function display($string); // does the display in its own way
   }
   
   class nullDisplay implements myDisplayInterface {
       // implements myDisplayInterface but does nothing
       public function display($string) {}
   }
   
   class x2 {
       public $display = null;
       
       public function __construct() {
           $this->display = new nullDisplay();
       }
       
       function foo($string) {
           // Keep the check, as $display is public, and may get wrong values
           if ($this->display instanceof myDisplayInterface) {
               $display->display();
           } else {
               print "Error when displaying\n";
           }
       }
   }
   
   // Simple class for echo
   class echoDisplay implements myDisplayInterface {
       // implements myDisplayInterface but does nothing
       public function display($string) {
           echo $string;
       }
   }
   
   ?>

See also `Null Object Pattern <https://en.wikipedia.org/wiki/Null_Object_pattern#PHP>`_ and `The Null Object Pattern <https://www.sitepoint.com/the-null-object-pattern-polymorphism-in-domain-models/>`_.


Suggestions
___________

* Only use one type of syntax with your properties.




Specs
_____

+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Short name   | Classes/ScalarOrObjectProperty                                                                                          |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Rulesets     | :ref:`All <ruleset-All>`, :ref:`Analyze <ruleset-Analyze>`                                                              |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Exakat since | 0.12.3                                                                                                                  |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| PHP Version  | All                                                                                                                     |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Severity     | Minor                                                                                                                   |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Time To Fix  | Slow (1 hour)                                                                                                           |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Precision    | High                                                                                                                    |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Features     | object, scalar-typehint                                                                                                 |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Examples     | :ref:`case-sugarcrm-classes-scalarorobjectproperty`                                                                     |
+--------------+-------------------------------------------------------------------------------------------------------------------------+
| Available in | `Entreprise Edition <https://www.exakat.io/entreprise-edition>`_, `Exakat Cloud <https://www.exakat.io/exakat-cloud/>`_ |
+--------------+-------------------------------------------------------------------------------------------------------------------------+