lib/grade/grade_object.php

   1 <?php // $Id$
   2
   3 ///////////////////////////////////////////////////////////////////////////
   4 //                                                                       //
   5 // NOTICE OF COPYRIGHT                                                   //
   6 //                                                                       //
   7 // Moodle - Modular Object-Oriented Dynamic Learning Environment         //
   8 //          http://moodle.com                                            //
   9 //                                                                       //
  10 // Copyright (C) 2001-2003  Martin Dougiamas  http://dougiamas.com       //
  11 //                                                                       //
  12 // This program is free software; you can redistribute it and/or modify  //
  13 // it under the terms of the GNU General Public License as published by  //
  14 // the Free Software Foundation; either version 2 of the License, or     //
  15 // (at your option) any later version.                                   //
  16 //                                                                       //
  17 // This program is distributed in the hope that it will be useful,       //
  18 // but WITHOUT ANY WARRANTY; without even the implied warranty of        //
  19 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
  20 // GNU General Public License for more details:                          //
  21 //                                                                       //
  22 //          http://www.gnu.org/copyleft/gpl.html                         //
  23 //                                                                       //
  24 ///////////////////////////////////////////////////////////////////////////
  25
  26 /**
  27  * An abstract object that holds methods and attributes common to all grade_* objects defined here.
  28  * @abstract
  29  */
  30 class grade_object {
  31     /**
  32      * Array of class variables that are not part of the DB table fields
  33      * @var array $nonfields
  34      */
  35     var $nonfields = array('nonfields', 'required_fields');
  36
  37     /**
  38      * Array of required fields (keys) and their default values (values).
  39      * @var array $required_fields
  40      */
  41     var $required_fields = array();
  42
  43     /**
  44      * The PK.
  45      * @var int $id
  46      */
  47     var $id;
  48
  49     /**
  50      * The first time this grade_calculation was created.
  51      * @var int $timecreated
  52      */
  53     var $timecreated;
  54
  55     /**
  56      * The last time this grade_calculation was modified.
  57      * @var int $timemodified
  58      */
  59     var $timemodified;
  60
  61     /**
  62      * Constructor. Optionally (and by default) attempts to fetch corresponding row from DB.
  63      * @param object $params an object with named parameters for this grade item.
  64      * @param boolean $fetch Whether to fetch corresponding row from DB or not.
  65      */
  66     function grade_object($params=NULL, $fetch = true) {
  67         if (!empty($params) && (is_array($params) || is_object($params))) {
  68             $this->assign_to_this($params);
  69
  70             if ($fetch) {
  71                 $records = $this->fetch_all_using_this();
  72                 if ($records && count($records) > 0) {
  73                     $this->assign_to_this(current($records));
  74                 }
  75             }
  76         }
  77     }
  78
  79     /**
  80      * Updates this object in the Database, based on its object variables. ID must be set.
  81      *
  82      * @return boolean
  83      */
  84     function update() {
  85         global $USER;
  86
  87         $this->timemodified = time();
  88
  89         if (empty($this->usermodified)) {
  90             $this->usermodified = $USER->id;
  91         }
  92
  93         return update_record($this->table, $this);
  94     }
  95
  96     /**
  97      * Deletes this object from the database.
  98      */
  99     function delete() {
 100         return delete_records($this->table, 'id', $this->id);
 101     }
 102
 103     /**
 104      * Records this object in the Database, sets its id to the returned value, and returns that value.
 105      * @return int PK ID if successful, false otherwise
 106      */
 107     function insert() {
 108         global $USER;
 109
 110         if (!empty($this->id)) {   // Object already exists, so let's do an update instead
 111             $this->update();
 112         }
 113
 114         $this->timecreated = $this->timemodified = time();
 115
 116         if (empty($this->usermodified)) {
 117             $this->usermodified = $USER->id;
 118         }
 119
 120         $clonethis = clone($this);
 121
 122         // Unset non-set fields
 123         foreach ($clonethis as $var => $val) {
 124             if (!isset($val)) {
 125                 unset($clonethis->$var);
 126             }
 127         }
 128
 129         return $this->id = insert_record($this->table, $clonethis, true);
 130     }
 131
 132     /**
 133      * Using this object's id field, fetches the matching record in the DB, and looks at
 134      * each variable in turn. If the DB has different data, the db's data is used to update
 135      * the object. This is different from the update() function, which acts on the DB record
 136      * based on the object.
 137      */
 138     function update_from_db() {
 139         if (empty($this->id)) {
 140             debugging("The object could not be used in its state to retrieve a matching record from the DB, because it's id field is not set.");
 141             return false;
 142         } else {
 143             $class = get_class($this);
 144             $object = new $class(array('id' => $this->id));
 145             foreach ($object as $var => $val) {
 146                 if ($this->$var != $val) {
 147                     $this->$var = $val;
 148                 }
 149             }
 150         }
 151         return true;
 152     }
 153
 154     /**
 155      * Uses the variables of this object to retrieve all matching objects from the DB.
 156      * @return array $objects
 157      */
 158     function fetch_all_using_this() {
 159         $variables = get_object_vars($this);
 160         $wheresql = '';
 161
 162         foreach ($variables as $var => $value) {
 163             if (!empty($value) && !in_array($var, $this->nonfields)) {
 164                 $wheresql .= " $var = '$value' AND ";
 165             }
 166         }
 167
 168         // Trim trailing AND
 169         $wheresql = substr($wheresql, 0, strrpos($wheresql, 'AND'));
 170
 171         $objects = get_records_select($this->table, $wheresql, 'id');
 172
 173         if (!empty($objects)) {
 174             $full_objects = array();
 175
 176             // Convert the stdClass objects returned by the get_records_select method into proper objects
 177             $classname = get_class($this);
 178             foreach ($objects as $id => $stdobject) {
 179                 $full_objects[$id] = new $classname($stdobject, false);
 180             }
 181             return $full_objects;
 182         } else {
 183             return $objects;
 184         }
 185     }
 186
 187
 188     /**
 189      * Given an associated array or object, cycles through each key/variable
 190      * and assigns the value to the corresponding variable in this object.
 191      */
 192     function assign_to_this($params) {
 193         foreach ($params as $param => $value) {
 194             if (in_object_vars($param, $this)) {
 195                 $this->$param = $value;
 196             }
 197         }
 198     }
 199
 200 }
 201 ?>