1: <?php
 2: 
 3: namespace Cron;
 4: 
 5: /**
 6:  * CRON field factory implementing a flyweight factory
 7:  * @link http://en.wikipedia.org/wiki/Cron
 8:  */
 9: class FieldFactory
10: {
11:     /**
12:      * @var array Cache of instantiated fields
13:      */
14:     private $fields = array();
15: 
16:     /**
17:      * Get an instance of a field object for a cron expression position
18:      *
19:      * @param int $position CRON expression position value to retrieve
20:      *
21:      * @return FieldInterface
22:      * @throws InvalidArgumentException if a position is not valid
23:      */
24:     public function getField($position)
25:     {
26:         if (!isset($this->fields[$position])) {
27:             switch ($position) {
28:                 case 0:
29:                     $this->fields[$position] = new MinutesField();
30:                     break;
31:                 case 1:
32:                     $this->fields[$position] = new HoursField();
33:                     break;
34:                 case 2:
35:                     $this->fields[$position] = new DayOfMonthField();
36:                     break;
37:                 case 3:
38:                     $this->fields[$position] = new MonthField();
39:                     break;
40:                 case 4:
41:                     $this->fields[$position] = new DayOfWeekField();
42:                     break;
43:                 case 5:
44:                     $this->fields[$position] = new YearField();
45:                     break;
46:                 default:
47:                     throw new \InvalidArgumentException(
48:                         $position . ' is not a valid position'
49:                     );
50:             }
51:         }
52: 
53:         return $this->fields[$position];
54:     }
55: }
56: