application/hub/main/handler/tasks/class_TaskHandler.php

   1 <?php
   2 /**
   3  * A Task handler
   4  *
   5  * @author              Roland Haeder <webmaster@ship-simu.org>
   6  * @version             0.0.0
   7  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009, 2010 Hub Developer Team
   8  * @license             GNU GPL 3.0 or any newer version
   9  * @link                http://www.ship-simu.org
  10  *
  11  * This program is free software: you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation, either version 3 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License
  22  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  23  */
  24 class TaskHandler extends BaseHandler implements Registerable, HandleableTask {
  25         // Exception constants
  26         const EXCEPTION_TASK_IS_INVALID = 0xb00;
  27
  28         /**
  29          * Visitor instance for all tasks while they are active
  30          */
  31         private $visitorInstance = null;
  32
  33         /**
  34          * Protected constructor
  35          *
  36          * @return      void
  37          */
  38         protected function __construct () {
  39                 // Call parent constructor
  40                 parent::__construct(__CLASS__);
  41
  42                 // Set handler name
  43                 $this->setHandlerName('task');
  44
  45                 // Init the task list
  46                 $this->setListInstance(ObjectFactory::createObjectByConfiguredName('task_list_class'));
  47
  48                 // Get default instance
  49                 $this->setIteratorInstance($this->getListInstance()->getIterator());
  50
  51                 // Init visitor instance for faster loop
  52                 $this->visitorInstance = ObjectFactory::createObjectByConfiguredName('active_task_visitor_class');
  53         }
  54
  55         /**
  56          * Creates an instance of this class
  57          *
  58          * @return      $handlerInstance        An instance of a HandleableTask class
  59          */
  60         public static final function createTaskHandler () {
  61                 // Get new instance
  62                 $handlerInstance = new TaskHandler();
  63
  64                 // Output debug message
  65                 $handlerInstance->debugOutput('TASK-HANDLER: Task handler initialized.');
  66
  67                 // Return the prepared instance
  68                 return $handlerInstance;
  69         }
  70
  71         /**
  72          * Tries to execute the given task. If as task should not be started (yet)
  73          * or the interval time (see task_interval_delay) is not yet reached the
  74          * task is quietly skipped.
  75          *
  76          * @return      void
  77          * @throws      InvalidTaskException    If the current task is invalid
  78          */
  79         private function executeCurrentTask () {
  80                 // Update no task by default
  81                 $updateTask = false;
  82
  83                 // Is the current task valid?
  84                 if (!$this->getIteratorInstance()->valid()) {
  85                         // Not valid!
  86                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  87                 } // END - if
  88
  89                 // Get current task
  90                 $currentTask = $this->getIteratorInstance()->current();
  91
  92                 // Is the task not yet started?
  93                 if ($currentTask['task_started'] === false) {
  94                         // Determine difference between current time and registration
  95                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
  96
  97                         // Should we start now?
  98                         if ($diff < $currentTask['task_startup_delay']) {
  99                                 // Skip this silently
 100                                 return false;
 101                         } // END - if
 102
 103                         // Launch the task and mark it as updated
 104                         $currentTask['task_started'] = true;
 105                         $updateTask = true;
 106
 107                         // Debug message
 108                         $this->debugOutput('TASK-HANDLER: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 109                 } // END - if
 110
 111                 // Get time difference from interval delay
 112                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 113
 114                 // Is the interval delay reached?
 115                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_total_runs'] == $currentTask['task_max_runs']) && ($currentTask['task_max_runs'] > 0))) {
 116                         // Should we update the task from startup?
 117                         if ($updateTask === true) {
 118                                 // Update the task before leaving
 119                                 $this->updateTask($currentTask);
 120                         } // END - if
 121
 122                         // Skip this silently
 123                         return false;
 124                 } // END - if
 125
 126                 // Set last activity
 127                 $currentTask['task_last_activity'] = $this->getMilliTime();
 128
 129                 // Count this run
 130                 $currentTask['task_total_runs']++;
 131
 132                 // Update the task
 133                 $this->updateTask($currentTask);
 134
 135                 // And visit/run it
 136                 // @TODO Messurement can be added around this call
 137                 $currentTask['task_instance']->accept($this->visitorInstance);
 138         }
 139
 140         /**
 141          * Updates given task by updating the underlaying list
 142          *
 143          * @param       $taskEntry      An array with a task
 144          * @return      void
 145          */
 146         private function updateTask (array $taskEntry) {
 147                 // Get the key from current iteration
 148                 $key = $this->getIteratorInstance()->key();
 149
 150                 // Get the hash from key
 151                 $hash = $this->getListInstance()->getHash($key);
 152
 153                 // Update the entry
 154                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 155         }
 156
 157         /**
 158          * Unregisters the given task
 159          *
 160          * @param       $taskData       Data of the task
 161          * @return      void
 162          */
 163         private function unregisterTask (array $taskData) {
 164                 // Debug output
 165                 $this->debugOutput('TASK-HANDLER: Removing task ' . $taskData['id'] . ' from queue - START');
 166
 167                 // Remove the entry
 168                 $this->getListInstance()->removeEntry('tasks', $taskData);
 169
 170                 // Debug output
 171                 $this->debugOutput('TASK-HANDLER: Removing task ' . $taskData['id'] . ' from queue - FINISHED');
 172          }
 173
 174         /**
 175          * Registers a task with a task handler.
 176          *
 177          * @param       $taskName               A task name to register the task on
 178          * @param       $taskInstance   The instance we should register as a task
 179          * @return      void
 180          */
 181         public function registerTask ($taskName, Visitable $taskInstance) {
 182                 // Create the entry
 183                 $taskEntry = array(
 184                         // Identifier for the generateHash() method
 185                         'id'                  => $taskName,
 186                         // Wether the task is started
 187                         'task_started'        => false,
 188                         // Wether the task is paused (not yet implemented)
 189                         'task_paused'         => false,
 190                         // Wether the task can be paused (not yet implemented)
 191                         'task_pauseable'      => true,
 192                         // Timestamp of registration
 193                         'task_registered'     => $this->getMilliTime(),
 194                         // Last activity timestamp
 195                         'task_last_activity'  => 0,
 196                         // Total runs of this task
 197                         'task_total_runs'     => 0,
 198                         // Task instance itself
 199                         'task_instance'       => $taskInstance,
 200                         // Startup delay in milliseconds
 201                         'task_startup_delay'  => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay'),
 202                         // Interval time (delay) in milliseconds before this task is executed again
 203                         'task_interval_delay' => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay'),
 204                         // How often should this task run?
 205                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 206                 );
 207
 208                 // Add the entry
 209                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 210
 211                 // Debug message
 212                 $this->debugOutput('TASK-HANDLER: Task ' . $taskName .
 213                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 214                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 215                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 216                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' times registered.'
 217                 );
 218         }
 219
 220         /**
 221          * Checks wether tasks are left including idle task
 222          *
 223          * @return      $tasksLeft      Wether there are tasks left to handle
 224          */
 225         public function hasTasksLeft () {
 226                 // Do we have tasks there?
 227                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 228
 229                 // Return result
 230                 return $tasksLeft;
 231         }
 232
 233         /**
 234          * Handles all tasks by checking if they should startup or if it is their
 235          * turn to run. You should use this method in a while() loop in conjuntion
 236          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 237          * which will attempt to remove all tasks from the task handler.
 238          *
 239          * @return      void
 240          */
 241         public function handleTasks () {
 242                 // Should we rewind?
 243                 if (!$this->getIteratorInstance()->valid()) {
 244                         // Rewind to the beginning for next loop
 245                         $this->getIteratorInstance()->rewind();
 246                 } // END - if
 247
 248                 // Try to execute the task
 249                 $this->executeCurrentTask();
 250
 251                 // Go to next entry
 252                 $this->getIteratorInstance()->next();
 253         }
 254
 255         /**
 256          * Shuts down all tasks and the task handler itself. This method should be
 257          * called from a corresponding filter class.
 258          *
 259          * @return      void
 260          */
 261         public function doShutdown () {
 262                 // Should we rewind?
 263                 if (!$this->getIteratorInstance()->valid()) {
 264                         // Rewind to the beginning for next loop
 265                         $this->getIteratorInstance()->rewind();
 266                 } // END - if
 267
 268                 // Debug message
 269                 $this->debugOutput('TASK-HANDLER: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 270
 271                 // Remember all tasks that has been shutdown for removal
 272                 $tasks = array();
 273
 274                 // Instance a visitor
 275                 $this->visitorInstance = ObjectFactory::createObjectByConfiguredName('shutdown_task_visitor_class');
 276
 277                 // Shutdown all tasks in once go
 278                 while ($this->getIteratorInstance()->valid()) {
 279                         // Get current entry
 280                         $currentTask = $this->getIteratorInstance()->current();
 281
 282                         // Output debug message
 283                         $this->debugOutput('TASK-HANDLER: Shutting down task ' . $currentTask['id'] . ' (taskInstance=' . $currentTask['task_instance']->__toString() . ') ...');
 284
 285                         // Shutdown the task
 286                         $currentTask['task_instance']->accept($this->visitorInstance);
 287
 288                         // Remember this task
 289                         $tasks[] = $currentTask;
 290
 291                         // Advance to next one
 292                         $this->getIteratorInstance()->next();
 293                 } // END - while
 294
 295
 296                 // Debug message
 297                 $this->debugOutput('TASK-HANDLER: Shutdown of all tasks completed.');
 298
 299                 // Remove all tasks
 300                 foreach ($tasks as $entry) {
 301                         $this->unregisterTask($entry);
 302                 } // END - foreach
 303         }
 304 }
 305
 306 // [EOF]
 307 ?>