CommandChain.class.php

Go to the documentation of this file.
00001 <?php
00002 /***************************************************************************
00003  *   Copyright (C) 2006-2007 by Konstantin V. Arkhipov                     *
00004  *                                                                         *
00005  *   This program is free software; you can redistribute it and/or modify  *
00006  *   it under the terms of the GNU Lesser General Public License as        *
00007  *   published by the Free Software Foundation; either version 3 of the    *
00008  *   License, or (at your option) any later version.                       *
00009  *                                                                         *
00010  ***************************************************************************/
00011 
00015     final class CommandChain implements EditorCommand
00016     {
00017         private $chain = array();
00018         
00022         public static function create()
00023         {
00024             return new self;
00025         }
00026         
00030         public function add(EditorCommand $command)
00031         {
00032             $this->chain[] = $command;
00033             
00034             return $this;
00035         }
00036         
00041         public function run(Prototyped $subject, Form $form, HttpRequest $request)
00042         {
00043             Assert::isTrue(
00044                 ($size = count($this->chain)) > 0,
00045                 
00046                 'command chain is empty'
00047             );
00048             
00049             for ($i = 0; $i < $size; ++$i) {
00050                 $command = &$this->chain[$i];
00051                 
00052                 try {
00053                     $mav = $command->run($subject, $form, $request);
00054                     
00055                     if ($mav->getView() == EditorController::COMMAND_FAILED) {
00056                         $this->rollback($i);
00057                         return $mav;
00058                     }
00059                 } catch (BaseException $e) {
00060                     $this->rollback($i);
00061                     throw $e;
00062                 }
00063             }
00064             
00065             return $mav;
00066         }
00067         
00071         private function rollback($position)
00072         {
00073             for ($i = $position; $i > -1; --$i) {
00074                 if ($this->chain[$i] instanceof CarefulCommand) {
00075                     try {
00076                         $this->chain[$i]->rollback();
00077                     } catch (BaseException $e) {
00078                         // silently ignore, since no one
00079                         // allowed to interrupt this proccess
00080                     }
00081                 }
00082             }
00083             
00084             return $this;
00085         }
00086         
00090         private function commit()
00091         {
00092             for ($size = count($this->chain), $i = 0; $i < $size; --$i) {
00093                 if ($this->chain[$i] instanceof CarefulCommand)
00094                     $this->chain[$i]->commit();
00095             }
00096             
00097             return $this;
00098         }
00099     }
00100 ?>