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 - 2011 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                 // Register the first (and generic) idle-loop task
  68                 $taskInstance = ObjectFactory::createObjectByConfiguredName('idle_task_class');
  69                 $handlerInstance->registerTask('idle_loop', $taskInstance);
  70
  71                 // Return the prepared instance
  72                 return $handlerInstance;
  73         }
  74
  75         /**
  76          * Tries to execute the given task. If as task should not be started (yet)
  77          * or the interval time (see task_interval_delay) is not yet reached the
  78          * task is quietly skipped.
  79          *
  80          * @return      void
  81          * @throws      InvalidTaskException    If the current task is invalid
  82          */
  83         private function executeCurrentTask () {
  84                 // Update no task by default
  85                 $updateTask = false;
  86
  87                 // Is the current task valid?
  88                 if (!$this->getIteratorInstance()->valid()) {
  89                         // Not valid!
  90                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  91                 } // END - if
  92
  93                 // Get current task
  94                 $currentTask = $this->getIteratorInstance()->current();
  95
  96                 // Is the task not yet started?
  97                 if ($currentTask['task_started'] === false) {
  98                         // Determine difference between current time and registration
  99                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
 100
 101                         // Should we start now?
 102                         if ($diff < $currentTask['task_startup_delay']) {
 103                                 // Skip this silently
 104                                 return false;
 105                         } // END - if
 106
 107                         // Launch the task and mark it as updated
 108                         $currentTask['task_started'] = true;
 109                         $updateTask = true;
 110
 111                         // Debug message
 112                         $this->debugOutput('TASK-HANDLER: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 113                 } // END - if
 114
 115                 // Get time difference from interval delay
 116                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 117
 118                 // Is the interval delay reached?
 119                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_total_runs'] == $currentTask['task_max_runs']) && ($currentTask['task_max_runs'] > 0))) {
 120                         // Should we update the task from startup?
 121                         if ($updateTask === true) {
 122                                 // Update the task before leaving
 123                                 $this->updateTask($currentTask);
 124                         } // END - if
 125
 126                         // Skip this silently
 127                         return false;
 128                 } // END - if
 129
 130                 // Set last activity
 131                 $currentTask['task_last_activity'] = $this->getMilliTime();
 132
 133                 // Count this run
 134                 $currentTask['task_total_runs']++;
 135
 136                 // Update the task
 137                 $this->updateTask($currentTask);
 138
 139                 // And visit/run it
 140                 // @TODO Messurement can be added around this call
 141                 $currentTask['task_instance']->accept($this->visitorInstance);
 142         }
 143
 144         /**
 145          * Updates given task by updating the underlaying list
 146          *
 147          * @param       $taskEntry      An array with a task
 148          * @return      void
 149          */
 150         private function updateTask (array $taskEntry) {
 151                 // Get the key from current iteration
 152                 $key = $this->getIteratorInstance()->key();
 153
 154                 // Get the hash from key
 155                 $hash = $this->getListInstance()->getHash($key);
 156
 157                 // Update the entry
 158                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 159         }
 160
 161         /**
 162          * Unregisters the given task
 163          *
 164          * @param       $taskData       Data of the task
 165          * @return      void
 166          */
 167         private function unregisterTask (array $taskData) {
 168                 // Debug output
 169                 $this->debugOutput('TASK-HANDLER: Removing task ' . $taskData['id'] . ' from queue - START');
 170
 171                 // Remove the entry
 172                 $this->getListInstance()->removeEntry('tasks', $taskData);
 173
 174                 // Debug output
 175                 $this->debugOutput('TASK-HANDLER: Removing task ' . $taskData['id'] . ' from queue - FINISHED');
 176          }
 177
 178         /**
 179          * Registers a task with a task handler.
 180          *
 181          * @param       $taskName               A task name to register the task on
 182          * @param       $taskInstance   The instance we should register as a task
 183          * @return      void
 184          */
 185         public function registerTask ($taskName, Visitable $taskInstance) {
 186                 // Create the entry
 187                 $taskEntry = array(
 188                         // Identifier for the generateHash() method
 189                         'id'                  => $taskName,
 190                         // Wether the task is started
 191                         'task_started'        => false,
 192                         // Wether the task is paused (not yet implemented)
 193                         'task_paused'         => false,
 194                         // Wether the task can be paused (not yet implemented)
 195                         'task_pauseable'      => true,
 196                         // Timestamp of registration
 197                         'task_registered'     => $this->getMilliTime(),
 198                         // Last activity timestamp
 199                         'task_last_activity'  => 0,
 200                         // Total runs of this task
 201                         'task_total_runs'     => 0,
 202                         // Task instance itself
 203                         'task_instance'       => $taskInstance,
 204                         // Startup delay in milliseconds
 205                         'task_startup_delay'  => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay'),
 206                         // Interval time (delay) in milliseconds before this task is executed again
 207                         'task_interval_delay' => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay'),
 208                         // How often should this task run?
 209                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 210                 );
 211
 212                 // Add the entry
 213                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 214
 215                 // Debug message
 216                 $this->debugOutput('TASK-HANDLER: Task ' . $taskName .
 217                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 218                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 219                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 220                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' times registered.'
 221                 );
 222         }
 223
 224         /**
 225          * Checks wether tasks are left including idle task
 226          *
 227          * @return      $tasksLeft      Wether there are tasks left to handle
 228          */
 229         public function hasTasksLeft () {
 230                 // Do we have tasks there?
 231                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 232
 233                 // Return result
 234                 return $tasksLeft;
 235         }
 236
 237         /**
 238          * Handles all tasks by checking if they should startup or if it is their
 239          * turn to run. You should use this method in a while() loop in conjuntion
 240          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 241          * which will attempt to remove all tasks from the task handler.
 242          *
 243          * @return      void
 244          */
 245         public function handleTasks () {
 246                 // Should we rewind?
 247                 if (!$this->getIteratorInstance()->valid()) {
 248                         // Rewind to the beginning for next loop
 249                         $this->getIteratorInstance()->rewind();
 250                 } // END - if
 251
 252                 // Try to execute the task
 253                 $this->executeCurrentTask();
 254
 255                 // Go to next entry
 256                 $this->getIteratorInstance()->next();
 257         }
 258
 259         /**
 260          * Shuts down all tasks and the task handler itself. This method should be
 261          * called from a corresponding filter class.
 262          *
 263          * @return      void
 264          */
 265         public function doShutdown () {
 266                 // Should we rewind?
 267                 if (!$this->getIteratorInstance()->valid()) {
 268                         // Rewind to the beginning for next loop
 269                         $this->getIteratorInstance()->rewind();
 270                 } // END - if
 271
 272                 // Debug message
 273                 $this->debugOutput('TASK-HANDLER: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 274
 275                 // Remember all tasks that has been shutdown for removal
 276                 $tasks = array();
 277
 278                 // Instance a visitor
 279                 $this->visitorInstance = ObjectFactory::createObjectByConfiguredName('shutdown_task_visitor_class');
 280
 281                 // Shutdown all tasks in once go
 282                 while ($this->getIteratorInstance()->valid()) {
 283                         // Get current entry
 284                         $currentTask = $this->getIteratorInstance()->current();
 285
 286                         // Output debug message
 287                         $this->debugOutput('TASK-HANDLER: Shutting down task ' . $currentTask['id'] . ' (taskInstance=' . $currentTask['task_instance']->__toString() . ') ...');
 288
 289                         // Shutdown the task
 290                         $currentTask['task_instance']->accept($this->visitorInstance);
 291
 292                         // Remember this task
 293                         $tasks[] = $currentTask;
 294
 295                         // Advance to next one
 296                         $this->getIteratorInstance()->next();
 297                 } // END - while
 298
 299
 300                 // Debug message
 301                 $this->debugOutput('TASK-HANDLER: Shutdown of all tasks completed.');
 302
 303                 // Remove all tasks
 304                 foreach ($tasks as $entry) {
 305                         $this->unregisterTask($entry);
 306                 } // END - foreach
 307         }
 308 }
 309
 310 // [EOF]
 311 ?>