[Summary view]

   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  namespace core_question\local\bank;
  18  
  19  /**
  20   * Abstract class to define functionality shared by all pluggable components used in the question bank view.
  21   *
  22   * @package   core_question
  23   * @copyright 2023 onwards Catalyst IT EU {@link https://catalyst-eu.net}
  24   * @author    Mark Johnson <mark.johnson@catalyst-eu.net>
  25   * @license   http://www.gnu.org/copyleft/gpl.html GNU GPL v3 or later
  26   */
  27  abstract class view_component {
  28  
  29      /** @var view Question bank view. */
  30      protected $qbank;
  31  
  32      /**
  33       * Constructor.
  34       * @param view $qbank the question bank view we are helping to render.
  35       */
  36      public function __construct(view $qbank) {
  37          $this->qbank = $qbank;
  38          $this->init();
  39      }
  40  
  41      /**
  42       * A chance for subclasses to initialise themselves, for example to load lang strings,
  43       * without having to override the constructor.
  44       */
  45      protected function init(): void {
  46      }
  47  
  48      /**
  49       * Return an array 'table_alias' => 'JOIN clause' to bring in any data that
  50       * this feature requires.
  51       *
  52       * The return values for all the features will be checked. It is OK if two
  53       * features join in the same table with the same alias and identical JOIN clauses.
  54       * If two features try to use the same alias with different joins, you get an error.
  55       * Tables included by default are question (alias q) and those defined in {@see view::get_required_joins()}
  56       *
  57       * It is importnat that your join simply adds additional data (or NULLs) to the
  58       * existing rows of the query. It must not cause additional rows.
  59       *
  60       * @return string[] 'table_alias' => 'JOIN clause'
  61       */
  62      public function get_extra_joins(): array {
  63          return [];
  64      }
  65  
  66      /**
  67       * Use table alias 'q' for the question table, or one of the
  68       * ones from get_extra_joins. Every field requested must specify a table prefix.
  69       *
  70       * @return string[] fields required.
  71       */
  72      public function get_required_fields(): array {
  73          return [];
  74      }
  75  }