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                 // Init the task list
  43                 $this->setListInstance(ObjectFactory::createObjectByConfiguredName('task_list_class'));
  44
  45                 // Get default instance
  46                 $this->setIteratorInstance($this->getListInstance()->getIterator());
  47
  48                 // Init visitor instance for faster loop
  49                 $this->visitorInstance = ObjectFactory::createObjectByConfiguredName('active_task_visitor_class');
  50         }
  51
  52         /**
  53          * Creates an instance of this class
  54          *
  55          * @return      $handlerInstance        An instance of a HandleableTask class
  56          */
  57         public final static function createTaskHandler () {
  58                 // Get new instance
  59                 $handlerInstance = new TaskHandler();
  60
  61                 // Output debug message
  62                 $handlerInstance->debugOutput('TASK-HANDLER: Task handler initialized.');
  63
  64                 // Return the prepared instance
  65                 return $handlerInstance;
  66         }
  67
  68         /**
  69          * Tries to execute the given task. If as task should not be started (yet)
  70          * or the interval time (see task_interval_delay) is not yet reached the
  71          * task is quietly skipped.
  72          *
  73          * @return      void
  74          * @throws      InvalidTaskException    If the current task is invalid
  75          */
  76         private function executeCurrentTask () {
  77                 // Update no task by default
  78                 $updateTask = false;
  79
  80                 // Is the current task valid?
  81                 if (!$this->getIteratorInstance()->valid()) {
  82                         // Not valid!
  83                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  84                 } // END - if
  85
  86                 // Get current task
  87                 $currentTask = $this->getIteratorInstance()->current();
  88
  89                 // Is the task not yet started?
  90                 if ($currentTask['task_started'] === false) {
  91                         // Determine difference between current time and registration
  92                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
  93
  94                         // Should we start now?
  95                         if ($diff < $currentTask['task_startup_delay']) {
  96                                 // Skip this silently
  97                                 return false;
  98                         } // END - if
  99
 100                         // Launch the task and mark it as updated
 101                         $currentTask['task_started'] = true;
 102                         $updateTask = true;
 103
 104                         // Debug message
 105                         $this->debugOutput('TASK-HANDLER: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 106                 } // END - if
 107
 108                 // Get time difference from interval delay
 109                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 110
 111                 // Is the interval delay reached?
 112                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_total_runs'] == $currentTask['task_max_runs']) && ($currentTask['task_max_runs'] > 0))) {
 113                         // Should we update the task from startup?
 114                         if ($updateTask === true) {
 115                                 // Update the task before leaving
 116                                 $this->updateTask($currentTask);
 117                         } // END - if
 118
 119                         // Skip this silently
 120                         return false;
 121                 } // END - if
 122
 123                 // Set last activity
 124                 $currentTask['task_last_activity'] = $this->getMilliTime();
 125
 126                 // Count this run
 127                 $currentTask['task_total_runs']++;
 128
 129                 // Update the task
 130                 $this->updateTask($currentTask);
 131
 132                 // And visit/run it
 133                 // @TODO Messurement can be added around this call
 134                 $currentTask['task_instance']->accept($this->visitorInstance);
 135         }
 136
 137         /**
 138          * Updates given task by updating the underlaying list
 139          *
 140          * @param       $taskEntry      An array with a task
 141          * @return      void
 142          */
 143         private function updateTask (array $taskEntry) {
 144                 // Get the key from current iteration
 145                 $key = $this->getIteratorInstance()->key();
 146
 147                 // Get the hash from key
 148                 $hash = $this->getListInstance()->getHash($key);
 149
 150                 // Update the entry
 151                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 152         }
 153
 154         /**
 155          * Unregisters the given task
 156          *
 157          * @param       $taskName       Name of the task
 158          * @return      void
 159          */
 160          private function unregisterTask ($taskName) {
 161                 // Remove the entry
 162                 $this->getListInstance()->removeEntry('tasks', $taskName);
 163          }
 164
 165         /**
 166          * Registers a task with a task handler.
 167          *
 168          * @param       $taskName               A task name to register the task on
 169          * @param       $taskInstance   The instance we should register as a task
 170          * @return      void
 171          */
 172         public function registerTask ($taskName, Visitable $taskInstance) {
 173                 // Create the entry
 174                 $taskEntry = array(
 175                         // Identifier for the generateHash() method
 176                         'id'                  => $taskName,
 177                         // Wether the task is started
 178                         'task_started'        => false,
 179                         // Wether the task is paused (not yet implemented)
 180                         'task_paused'         => false,
 181                         // Wether the task can be paused (not yet implemented)
 182                         'task_pauseable'      => true,
 183                         // Timestamp of registration
 184                         'task_registered'     => $this->getMilliTime(),
 185                         // Last activity timestamp
 186                         'task_last_activity'  => 0,
 187                         // Total runs of this task
 188                         'task_total_runs'     => 0,
 189                         // Task instance itself
 190                         'task_instance'       => $taskInstance,
 191                         // Startup delay in milliseconds
 192                         'task_startup_delay'  => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay'),
 193                         // Interval time (delay) in milliseconds before this task is executed again
 194                         'task_interval_delay' => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay'),
 195                         // How often should this task run?
 196                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 197                 );
 198
 199                 // Add the entry
 200                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 201
 202                 // Debug message
 203                 $this->debugOutput('TASK-HANDLER: Task ' . $taskName .
 204                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 205                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 206                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 207                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' times registered.'
 208                 );
 209         }
 210
 211         /**
 212          * Checks wether tasks are left including idle task
 213          *
 214          * @return      $tasksLeft      Wether there are tasks left to handle
 215          */
 216         public function hasTasksLeft () {
 217                 // Do we have tasks there?
 218                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 219
 220                 // Return result
 221                 return $tasksLeft;
 222         }
 223
 224         /**
 225          * Handles all tasks by checking if they should startup or if it is their
 226          * turn to run. You should use this method in a while() loop in conjuntion
 227          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 228          * which will attempt to remove all tasks from the task handler.
 229          *
 230          * @return      void
 231          */
 232         public function handleTasks () {
 233                 // Should we rewind?
 234                 if (!$this->getIteratorInstance()->valid()) {
 235                         // Rewind to the beginning for next loop
 236                         $this->getIteratorInstance()->rewind();
 237                 } // END - if
 238
 239                 // Try to execute the task
 240                 $this->executeCurrentTask();
 241
 242                 // Go to next entry
 243                 $this->getIteratorInstance()->next();
 244         }
 245
 246         /**
 247          * Shuts down all tasks and the task handler itself. This method should be
 248          * called from a corresponding filter class.
 249          *
 250          * @return      void
 251          */
 252         public function doShutdown () {
 253                 // Should we rewind?
 254                 if (!$this->getIteratorInstance()->valid()) {
 255                         // Rewind to the beginning for next loop
 256                         $this->getIteratorInstance()->rewind();
 257                 } // END - if
 258
 259                 // Debug message
 260                 $this->debugOutput('TASK-HANDLER: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 261
 262                 // Remember all tasks that has been shutdown for removal
 263                 $tasks = array();
 264
 265                 // Shutdown all tasks in once go
 266                 while ($this->getIteratorInstance()->valid()) {
 267                         // Get current entry
 268                         $current = $this->getIteratorInstance()->current();
 269
 270                         // Output debug message
 271                         $this->debugOutput('TASK-HANDLER: Shutting down task ' . $current['id'] . ' (taskInstance=' . $current['task_instance']->__toString() . ') ...');
 272
 273                         // Shutdown the task
 274                         $current['task_instance']->doShutdown();
 275
 276                         // Remember this task
 277                         $tasks[] = $current;
 278
 279                         // Advance to next one
 280                         $this->getIteratorInstance()->next();
 281                 } // END - while
 282
 283
 284                 // Debug message
 285                 $this->debugOutput('TASK-HANDLER: Shutdown of all tasks completed.');
 286
 287                 // Remove all tasks
 288                 foreach ($tasks as $entry) {
 289                         $this->unregisterTask($entry);
 290                 } // END - foreach
 291         }
 292 }
 293
 294 // [EOF]
 295 ?>