moodle/lib/grade/grade_scale.php

<?php // $Id$

///////////////////////////////////////////////////////////////////////////
//                                                                       //
// NOTICE OF COPYRIGHT                                                   //
//                                                                       //
// Moodle - Modular Object-Oriented Dynamic Learning Environment         //
//          http://moodle.com                                            //
//                                                                       //
// Copyright (C) 2001-2003  Martin Dougiamas  http://dougiamas.com       //
//                                                                       //
// This program is free software; you can redistribute it and/or modify  //
// it under the terms of the GNU General Public License as published by  //
// the Free Software Foundation; either version 2 of the License, or     //
// (at your option) any later version.                                   //
//                                                                       //
// This program is distributed in the hope that it will be useful,       //
// but WITHOUT ANY WARRANTY; without even the implied warranty of        //
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         //
// GNU General Public License for more details:                          //
//                                                                       //
//          http://www.gnu.org/copyleft/gpl.html                         //
//                                                                       //
///////////////////////////////////////////////////////////////////////////

require_once('grade_object.php');

/**
 * Class representing a grade scale. It is responsible for handling its DB representation,
 * modifying and returning its metadata.
 */
class grade_scale extends grade_object {
    /**
     * DB Table (used by grade_object).
     * @var string $table
     */
    var $table = 'scale';

    /**
     * Array of class variables that are not part of the DB table fields
     * @var array $nonfields
     */
    var $nonfields = array('table', 'nonfields', 'scale_items');

    /**
     * The course this scale belongs to.
     * @var int $courseid
     */
    var $courseid;

    /**
     * The name of the scale.
     * @var string $name
     */
    var $name;

    /**
     * The items in this scale.
     * @var array $scale_items
     */
    var $scale_items = array();

    /**
     * A string representatin of the scale items (a comma-separated list).
     * @var string $scale
     */
    var $scale;

    /**
     * A description for this scale.
     * @var string $description
     */
    var $description;

    /**
     * Finds and returns a grade_scale object based on 1-3 field values.
     * @static
     *
     * @param string $field1
     * @param string $value1
     * @param string $field2
     * @param string $value2
     * @param string $field3
     * @param string $value3
     * @param string $fields
     * @return object grade_scale object or false if none found.
     */
    function fetch($field1, $value1, $field2='', $value2='', $field3='', $value3='', $fields="*") {
        if ($grade_scale = get_record('scale', $field1, $value1, $field2, $value2, $field3, $value3, $fields)) {
            $grade_scale = new grade_scale($grade_scale);
            return $grade_scale;

        } else {
            return false;
        }
    }

    /**
     * Loads the scale's items into the $scale_items array.
     * There are three ways to achieve this:
     * 1. No argument given: The $scale string is already loaded and exploded to an array of items.
     * 2. A string is given: A comma-separated list of items is exploded into an array of items.
     * 3. An array of items is given and saved directly as the array of items for this scale.
     *
     * @param mixed $items Could be null, a string or an array. The method behaves differently for each case.
     * @return array The resulting array of scale items or null if the method failed to produce one.
     */
    function load_items($items=NULL) {
        if (empty($items)) {
            $this->scale_items = explode(',', $this->scale);
        } elseif (is_array($items)) {
            $this->scale_items = $items;
        } else {
            $this->scale_items = explode(',', $items);
        }

        // Trim whitespace around each value
        foreach ($this->scale_items as $key => $val) {
            $this->scale_items[$key] = trim($val);
        }

        return $this->scale_items;
    }

    /**
     * Compacts (implodes) the array of items in $scale_items into a comma-separated string, $scale.
     * There are three ways to achieve this:
     * 1. No argument given: The $scale_items array is already loaded and imploded to a string of items.
     * 2. An array is given and is imploded into a string of items.
     * 3. A string of items is given and saved directly as the $scale variable.
     * NOTE: This method is the exact reverse of load_items, and their input/output should be interchangeable. However,
     * because load_items() trims the whitespace around the items, when the string is reconstructed these whitespaces will
     * be missing. This is not an issue, but should be kept in mind when comparing the two strings.
     *
     * @param mixed $items Could be null, a string or an array. The method behaves differently for each case.
     * @return array The resulting string of scale items or null if the method failed to produce one.
     */
    function compact_items($items=NULL) {
        if (empty($items)) {
            $this->scale = implode(',', $this->scale_items);
        } elseif (is_array($items)) {
            $this->scale = implode(',', $items);
        } else {
            $this->scale = $items;
        }

        return $this->scale;
    }
}
?>