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<?php
// This file is part of Moodle - http://moodle.org/
//
// Moodle 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 3 of the License, or
// (at your option) any later version.
//
// Moodle 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.
//
// You should have received a copy of the GNU General Public License
// along with Moodle. If not, see <http://www.gnu.org/licenses/>.
/**
* Base class for representing a column in a {@link question_bank_view}.
*
* @package core_question
* @copyright 1999 onwards Martin Dougiamas and others {@link http://moodle.com}
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
namespace core_question\bank;
defined('MOODLE_INTERNAL') || die();
/**
* Base class for representing a column in a {@link question_bank_view}.
*
* @copyright 2009 Tim Hunt
* @license http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
*/
abstract class column_base {
/**
* @var view $qbank the question bank view we are helping to render.
*/
protected $qbank;
/** @var bool determine whether the column is td or th. */
protected $isheading = false;
/**
* Constructor.
* @param view $qbank the question bank view we are helping to render.
*/
public function __construct(view $qbank) {
$this->qbank = $qbank;
$this->init();
}
/**
* A chance for subclasses to initialise themselves, for example to load lang strings,
* without having to override the constructor.
*/
protected function init() {
}
/**
* Set the column as heading
*/
public function set_as_heading() {
$this->isheading = true;
}
public function is_extra_row() {
return false;
}
/**
* Output the column header cell.
*/
public function display_header() {
echo '<th class="header ' . $this->get_classes() . '" scope="col">';
$sortable = $this->is_sortable();
$name = get_class($this);
$title = $this->get_title();
$tip = $this->get_title_tip();
if (is_array($sortable)) {
if ($title) {
echo '<div class="title">' . $title . '</div>';
}
$links = array();
foreach ($sortable as $subsort => $details) {
$links[] = $this->make_sort_link($name . '-' . $subsort,
$details['title'], isset($details['tip']) ? $details['tip'] : '', !empty($details['reverse']));
}
echo '<div class="sorters">' . implode(' / ', $links) . '</div>';
} else if ($sortable) {
echo $this->make_sort_link($name, $title, $tip);
} else {
if ($tip) {
echo '<span title="' . $tip . '">';
}
echo $title;
if ($tip) {
echo '</span>';
}
}
echo "</th>\n";
}
/**
* Title for this column. Not used if is_sortable returns an array.
*/
protected abstract function get_title();
/**
* @return string a fuller version of the name. Use this when get_title() returns
* something very short, and you want a longer version as a tool tip.
*/
protected function get_title_tip() {
return '';
}
/**
* Get a link that changes the sort order, and indicates the current sort state.
* @param string $sort the column to sort on.
* @param string $title the link text.
* @param string $tip the link tool-tip text. If empty, defaults to title.
* @param bool $defaultreverse whether the default sort order for this column is descending, rather than ascending.
* @return string HTML fragment.
*/
protected function make_sort_link($sort, $title, $tip, $defaultreverse = false) {
$currentsort = $this->qbank->get_primary_sort_order($sort);
$newsortreverse = $defaultreverse;
if ($currentsort) {
$newsortreverse = $currentsort > 0;
}
if (!$tip) {
$tip = $title;
}
if ($newsortreverse) {
$tip = get_string('sortbyxreverse', '', $tip);
} else {
$tip = get_string('sortbyx', '', $tip);
}
$link = '<a href="' . $this->qbank->new_sort_url($sort, $newsortreverse) . '" title="' . $tip . '">';
$link .= $title;
if ($currentsort) {
$link .= $this->get_sort_icon($currentsort < 0);
}
$link .= '</a>';
return $link;
}
/**
* Get an icon representing the corrent sort state.
* @param bool $reverse sort is descending, not ascending.
* @return string HTML image tag.
*/
protected function get_sort_icon($reverse) {
global $OUTPUT;
if ($reverse) {
return $OUTPUT->pix_icon('t/sort_desc', get_string('desc'), '', array('class' => 'iconsort'));
} else {
return $OUTPUT->pix_icon('t/sort_asc', get_string('asc'), '', array('class' => 'iconsort'));
}
}
/**
* Output this column.
* @param object $question the row from the $question table, augmented with extra information.
* @param string $rowclasses CSS class names that should be applied to this row of output.
*/
public function display($question, $rowclasses) {
$this->display_start($question, $rowclasses);
$this->display_content($question, $rowclasses);
$this->display_end($question, $rowclasses);
}
/**
* Output the opening column tag. If it is set as heading, it will use <th> tag instead of <td>
*
* @param \stdClass $question
* @param string $rowclasses
*/
protected function display_start($question, $rowclasses) {
$tag = 'td';
$attr = array('class' => $this->get_classes());
if ($this->isheading) {
$tag = 'th';
$attr['scope'] = 'row';
}
echo \html_writer::start_tag($tag, $attr);
}
/**
* @return string the CSS classes to apply to every cell in this column.
*/
protected function get_classes() {
$classes = $this->get_extra_classes();
$classes[] = $this->get_name();
return implode(' ', $classes);
}
/**
* Get the internal name for this column. Used as a CSS class name,
* and to store information about the current sort. Must match PARAM_ALPHA.
*
* @return string column name.
*/
public abstract function get_name();
/**
* @return array any extra class names you would like applied to every cell in this column.
*/
public function get_extra_classes() {
return array();
}
/**
* Output the contents of this column.
* @param object $question the row from the $question table, augmented with extra information.
* @param string $rowclasses CSS class names that should be applied to this row of output.
*/
protected abstract function display_content($question, $rowclasses);
/**
* Output the closing column tag
*
* @param object $question
* @param string $rowclasses
*/
protected function display_end($question, $rowclasses) {
$tag = 'td';
if ($this->isheading) {
$tag = 'th';
}
echo \html_writer::end_tag($tag);
}
/**
* Return an array 'table_alias' => 'JOIN clause' to bring in any data that
* this column required.
*
* The return values for all the columns will be checked. It is OK if two
* columns join in the same table with the same alias and identical JOIN clauses.
* If to columns try to use the same alias with different joins, you get an error.
* The only table included by default is the question table, which is aliased to 'q'.
*
* It is importnat that your join simply adds additional data (or NULLs) to the
* existing rows of the query. It must not cause additional rows.
*
* @return array 'table_alias' => 'JOIN clause'
*/
public function get_extra_joins() {
return array();
}
/**
* @return array fields required. use table alias 'q' for the question table, or one of the
* ones from get_extra_joins. Every field requested must specify a table prefix.
*/
public function get_required_fields() {
return array();
}
/**
* If this column needs extra data (e.g. tags) then load that here.
*
* The extra data should be added to the question object in the array.
* Probably a good idea to check that another column has not already
* loaded the data you want.
*
* @param \stdClass[] $questions the questions that will be displayed.
*/
public function load_additional_data(array $questions) {
}
/**
* Load the tags for each question.
*
* Helper that can be used from {@link load_additional_data()};
*
* @param array $questions
*/
public function load_question_tags(array $questions) {
$firstquestion = reset($questions);
if (isset($firstquestion->tags)) {
// Looks like tags are already loaded, so don't do it again.
return;
}
// Load the tags.
$tagdata = \core_tag_tag::get_items_tags('core_question', 'question',
array_keys($questions));
// Add them to the question objects.
foreach ($tagdata as $questionid => $tags) {
$questions[$questionid]->tags = $tags;
}
}
/**
* Can this column be sorted on? You can return either:
* + false for no (the default),
* + a field name, if sorting this column corresponds to sorting on that datbase field.
* + an array of subnames to sort on as follows
* return array(
* 'firstname' => array('field' => 'uc.firstname', 'title' => get_string('firstname')),
* 'lastname' => array('field' => 'uc.lastname', 'title' => get_string('lastname')),
* );
* As well as field, and field, you can also add 'revers' => 1 if you want the default sort
* order to be DESC.
* @return mixed as above.
*/
public function is_sortable() {
return false;
}
/**
* Helper method for building sort clauses.
* @param bool $reverse whether the normal direction should be reversed.
* @return string 'ASC' or 'DESC'
*/
protected function sortorder($reverse) {
if ($reverse) {
return ' DESC';
} else {
return ' ASC';
}
}
/**
* @param bool $reverse Whether to sort in the reverse of the default sort order.
* @param string $subsort if is_sortable returns an array of subnames, then this will be
* one of those. Otherwise will be empty.
* @return string some SQL to go in the order by clause.
*/
public function sort_expression($reverse, $subsort) {
$sortable = $this->is_sortable();
if (is_array($sortable)) {
if (array_key_exists($subsort, $sortable)) {
return $sortable[$subsort]['field'] . $this->sortorder($reverse);
} else {
throw new \coding_exception('Unexpected $subsort type: ' . $subsort);
}
} else if ($sortable) {
return $sortable . $this->sortorder($reverse);
} else {
throw new \coding_exception('sort_expression called on a non-sortable column.');
}
}
}