lib/form/grading.php

   1 <?php
   2 // This file is part of Moodle - http://moodle.org/
   3 //
   4 // Moodle is free software: you can redistribute it and/or modify
   5 // it under the terms of the GNU General Public License as published by
   6 // the Free Software Foundation, either version 3 of the License, or
   7 // (at your option) any later version.
   8 //
   9 // Moodle is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13 //
  14 // You should have received a copy of the GNU General Public License
  15 // along with Moodle.  If not, see <http://www.gnu.org/licenses/>.
  16
  17
  18 /**
  19  * Advance grading form element
  20  *
  21  * Element-container for advanced grading custom input
  22  *
  23  * @package   core_form
  24  * @copyright 2011 Marina Glancy
  25  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26  */
  27
  28 global $CFG;
  29 require_once("HTML/QuickForm/element.php");
  30 require_once($CFG->dirroot.'/grade/grading/form/lib.php');
  31
  32 if (class_exists('HTML_QuickForm')) {
  33     HTML_QuickForm::registerRule('gradingvalidated', 'callback', '_validate', 'MoodleQuickForm_grading');
  34 }
  35
  36 /**
  37  * Advance grading form element
  38  *
  39  * HTML class for a grading element. This is a wrapper for advanced grading plugins.
  40  * When adding the 'grading' element to the form, developer must pass an object of
  41  * class gradingform_instance as $attributes['gradinginstance']. Otherwise an exception will be
  42  * thrown.
  43  * This object is responsible for implementing functions to render element html and validate it
  44  *
  45  * @package   core_form
  46  * @category  form
  47  * @copyright 2011 Marina Glancy
  48  * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  49  */
  50 class MoodleQuickForm_grading extends HTML_QuickForm_input{
  51     /** @var string html for help button, if empty then no help */
  52     var $_helpbutton='';
  53
  54     /** @var array Stores attributes passed to the element */
  55     private $gradingattributes;
  56
  57     /**
  58      * Class constructor
  59      *
  60      * @param string $elementName Input field name attribute
  61      * @param mixed $elementLabel Label(s) for the input field
  62      * @param mixed $attributes Either a typical HTML attribute string or an associative array
  63      */
  64     public function MoodleQuickForm_grading($elementName=null, $elementLabel=null, $attributes=null) {
  65         parent::HTML_QuickForm_input($elementName, $elementLabel, $attributes);
  66         $this->gradingattributes = $attributes;
  67     }
  68
  69     /**
  70      * Helper function to retrieve gradingform_instance passed in element attributes
  71      *
  72      * @return gradingform_instance
  73      */
  74     public function get_gradinginstance() {
  75         if (is_array($this->gradingattributes) && array_key_exists('gradinginstance', $this->gradingattributes)) {
  76             return $this->gradingattributes['gradinginstance'];
  77         } else {
  78             return null;
  79         }
  80     }
  81
  82     /**
  83      * Returns the input field in HTML
  84      *
  85      * @return string
  86      */
  87     public function toHtml(){
  88         global $PAGE;
  89         return $this->get_gradinginstance()->render_grading_element($PAGE, $this);
  90     }
  91
  92     /**
  93      * get html for help button
  94      *
  95      * @return string html for help button
  96      */
  97     public function getHelpButton(){
  98         return $this->_helpbutton;
  99     }
 100
 101     /**
 102      * The renderer of gradingform_instance will take care itself about different display
 103      * in normal and frozen states
 104      *
 105      * @return string
 106      */
 107     public function getElementTemplateType(){
 108         return 'default';
 109     }
 110
 111     /**
 112      * Called by HTML_QuickForm whenever form event is made on this element.
 113      * Adds necessary rules to the element and checks that coorenct instance of gradingform_instance
 114      * is passed in attributes
 115      *
 116      * @param string $event Name of event
 117      * @param mixed $arg event arguments
 118      * @param object $caller calling object
 119      * @return bool
 120      * @throws moodle_exception
 121      */
 122     public function onQuickFormEvent($event, $arg, &$caller) {
 123         if ($event == 'createElement') {
 124             $attributes = $arg[2];
 125             if (!is_array($attributes) || !array_key_exists('gradinginstance', $attributes) || !($attributes['gradinginstance'] instanceof gradingform_instance)) {
 126                 throw new moodle_exception('exc_gradingformelement', 'grading');
 127             }
 128         }
 129
 130         $name = $this->getName();
 131         if ($name && $caller->elementExists($name)) {
 132             $caller->addRule($name, $this->get_gradinginstance()->default_validation_error_message(), 'gradingvalidated', $this->gradingattributes);
 133         }
 134         return parent::onQuickFormEvent($event, $arg, $caller);
 135     }
 136
 137     /**
 138      * Function registered as rule for this element and is called when this element is being validated.
 139      * This is a wrapper to pass the validation to the method gradingform_instance::validate_grading_element
 140      *
 141      * @param mixed $elementValue value of element to be validated
 142      * @param array $attributes element attributes
 143      * @return MoodleQuickForm_grading
 144      */
 145     static function _validate($elementValue, $attributes = null) {
 146         return $attributes['gradinginstance']->validate_grading_element($elementValue);
 147     }
 148 }