1 <?php
 2 /**
 3  * This class represents "transformations" of a form - such as making it printable or making it readonly.
 4  * The idea is that sometimes you will want to make your own such transformations, and you shouldn't have
 5  * to edit the underlying code to support this.
 6  * 
 7  * The first step in creating a transformation is subclassing FormTransformation.  After that, you have two
 8  * ways of defining specific functionality:
 9  *   - Define performMyTransformation() methods on each applicable FormField() object.
10  *   - Define transformFieldType($field) methods on your subclass of FormTransformation.
11  * 
12  * To actually perform the transformation, call $form->transform(new MyTransformation());
13  * @package forms
14  * @subpackage transformations
15  */
16 class FormTransformation extends Object {
17     function transform(FormField $field) {
18         // Look for a performXXTransformation() method on the field itself.
19         // performReadonlyTransformation() is a pretty commonly applied method.
20         // Otherwise, look for a transformXXXField() method on this object.
21         // This is more commonly done in custom transformations
22         
23         // We iterate through each array simultaneously, looking at [0] of both, then [1] of both.
24         // This provides a more natural failover scheme.
25         
26         $transNames = array_reverse(array_values(ClassInfo::ancestry($this->class)));
27         $fieldClasses = array_reverse(array_values(ClassInfo::ancestry($field->class)));
28         
29         $len = max(sizeof($transNames), sizeof($fieldClasses));
30         for($i=0;$i<$len;$i++) {
31             // This is lets fieldClasses be longer than transNames
32             if($transName = $transNames[$i]) {
33                 if($field->hasMethod('perform' . $transName)) {
34                     $funcName = 'perform' . $transName;
35                     //echo "<li>$field->class used $funcName";
36                     return $field->$funcName($this);
37                 }
38             }
39             
40             // And this one does the reverse.           
41             if($fieldClass = $fieldClasses[$i]) {
42                 if($this->hasMethod('transform' . $fieldClass)) {
43                     $funcName = 'transform' . $fieldClass;
44                     //echo "<li>$field->class used $funcName";
45                     return $this->$funcName($field);
46                 }
47             }
48         }
49         
50         user_error("FormTransformation:: Can't perform '$this->class' on '$field->class'", E_USER_ERROR);
51     }
52 }
53 
54 ?>