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 - 2012 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          * Protected constructor
  30          *
  31          * @return      void
  32          */
  33         protected function __construct () {
  34                 // Call parent constructor
  35                 parent::__construct(__CLASS__);
  36
  37                 // Set handler name
  38                 $this->setHandlerName('task');
  39         }
  40
  41         /**
  42          * Creates an instance of this class
  43          *
  44          * @return      $handlerInstance        An instance of a HandleableTask class
  45          */
  46         public static final function createTaskHandler () {
  47                 // Get new instance
  48                 $handlerInstance = new TaskHandler();
  49
  50                 // Output debug message
  51                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Initializing task handler.');
  52
  53                 // Init the task list
  54                 $handlerInstance->setListInstance(ObjectFactory::createObjectByConfiguredName('task_list_class'));
  55
  56                 // Get default instance
  57                 $handlerInstance->setIteratorInstance($handlerInstance->getListInstance()->getIterator());
  58
  59                 // Init visitor instance for faster loop
  60                 $handlerInstance->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('active_task_visitor_class'));
  61
  62                 // Register the first (and generic) idle-loop task
  63                 $taskInstance = ObjectFactory::createObjectByConfiguredName('idle_task_class');
  64                 $handlerInstance->registerTask('idle_loop', $taskInstance);
  65
  66                 // Output debug message
  67                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Task handler initialized.');
  68
  69                 // Return the prepared instance
  70                 return $handlerInstance;
  71         }
  72
  73         /**
  74          * Tries to execute the given task. If as task should not be started (yet)
  75          * or the interval time (see task_interval_delay) is not yet reached the
  76          * task is quietly skipped.
  77          *
  78          * @return      void
  79          * @throws      InvalidTaskException    If the current task is invalid
  80          */
  81         private function executeCurrentTask () {
  82                 // Update no task by default
  83                 $updateTask = false;
  84
  85                 // Is the current task valid?
  86                 if (!$this->getListInstance()->getIterator()->valid()) {
  87                         // Not valid!
  88                         throw new InvalidTaskException($this, self::EXCEPTION_TASK_IS_INVALID);
  89                 } // END - if
  90
  91                 // Get current task
  92                 $currentTask = $this->getListInstance()->getIterator()->current();
  93
  94                 // Is the task not yet started?
  95                 if ($currentTask['task_started'] === false) {
  96                         // Determine difference between current time and registration
  97                         $diff = ($this->getMilliTime() - $currentTask['task_registered']) * 1000;
  98
  99                         // Should we start now?
 100                         if ($diff < $currentTask['task_startup_delay']) {
 101                                 // Skip this silently
 102                                 return false;
 103                         } // END - if
 104
 105                         // Launch the task and mark it as updated
 106                         $currentTask['task_started'] = true;
 107                         $updateTask = true;
 108
 109                         // Debug message
 110                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Task ' . $currentTask['id'] . ' started with startup_delay=' . $currentTask['task_startup_delay'] . 'ms');
 111                 } // END - if
 112
 113                 // Get time difference from interval delay
 114                 $diff = ($this->getMilliTime() - $currentTask['task_last_activity']) * 1000;
 115
 116                 // Is the interval delay reached?
 117                 if ((($diff < $currentTask['task_interval_delay']) && ($currentTask['task_max_runs'] == 0)) || (($currentTask['task_total_runs'] == $currentTask['task_max_runs']) && ($currentTask['task_max_runs'] > 0))) {
 118                         // Should we update the task from startup?
 119                         if ($updateTask === true) {
 120                                 // Update the task before leaving
 121                                 $this->updateTask($currentTask);
 122                         } // END - if
 123
 124                         // Skip this silently
 125                         return false;
 126                 } // END - if
 127
 128                 // Set last activity
 129                 $currentTask['task_last_activity'] = $this->getMilliTime();
 130
 131                 // Count this run
 132                 $currentTask['task_total_runs']++;
 133
 134                 // Update the task
 135                 $this->updateTask($currentTask);
 136
 137                 // And visit/run it
 138                 // @TODO Messurement can be added around this call
 139                 $currentTask['task_instance']->accept($this->getVisitorInstance());
 140         }
 141
 142         /**
 143          * Updates given task by updating the underlaying list
 144          *
 145          * @param       $taskEntry      An array with a task
 146          * @return      void
 147          */
 148         private function updateTask (array $taskEntry) {
 149                 // Get the key from current iteration
 150                 $key = $this->getListInstance()->getIterator()->key();
 151
 152                 // Get the hash from key
 153                 $hash = $this->getListInstance()->getHash($key);
 154
 155                 // Update the entry
 156                 $this->getListInstance()->updateCurrentEntryByHash($hash, $taskEntry);
 157         }
 158
 159         /**
 160          * Unregisters the given task
 161          *
 162          * @param       $taskData       Data of the task
 163          * @return      void
 164          */
 165         private function unregisterTask (array $taskData) {
 166                 // Debug output
 167                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - START');
 168
 169                 // Remove the entry
 170                 $this->getListInstance()->removeEntry('tasks', $taskData);
 171
 172                 // Debug output
 173                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Removing task ' . $taskData['id'] . ' from queue - FINISHED');
 174          }
 175
 176         /**
 177          * Registers a task with a task handler.
 178          *
 179          * @param       $taskName               A task name to register the task on
 180          * @param       $taskInstance   The instance we should register as a task
 181          * @return      void
 182          */
 183         public function registerTask ($taskName, Visitable $taskInstance) {
 184                 // Create the entry
 185                 $taskEntry = array(
 186                         // Identifier for the generateHash() method
 187                         'id'                  => $taskName,
 188                         // Whether the task is started
 189                         'task_started'        => false,
 190                         // Whether the task is paused (not yet implemented)
 191                         'task_paused'         => false,
 192                         // Whether the task can be paused (not yet implemented)
 193                         'task_pauseable'      => true,
 194                         // Timestamp of registration
 195                         'task_registered'     => $this->getMilliTime(),
 196                         // Last activity timestamp
 197                         'task_last_activity'  => 0,
 198                         // Total runs of this task
 199                         'task_total_runs'     => 0,
 200                         // Task instance itself
 201                         'task_instance'       => $taskInstance,
 202                         // Startup delay in milliseconds
 203                         'task_startup_delay'  => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_startup_delay'),
 204                         // Interval time (delay) in milliseconds before this task is executed again
 205                         'task_interval_delay' => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_interval_delay'),
 206                         // How often should this task run?
 207                         'task_max_runs'       => $this->getConfigInstance()->getConfigEntry('task_' . $taskName . '_max_runs'),
 208                 );
 209
 210                 // Add the entry
 211                 $this->getListInstance()->addEntry('tasks', $taskEntry);
 212
 213                 // Debug message
 214                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Task registered: taskName=' . $taskName .
 215                         ' (taskInstance=' . $taskInstance->__toString() . ')' .
 216                         ', startupDelay=' . $taskEntry['task_startup_delay'] . 'ms' .
 217                         ', intervalDelay=' . $taskEntry['task_interval_delay'] . 'ms' .
 218                         ', maxRuns=' . $taskEntry['task_max_runs'] . ' ...'
 219                 );
 220         }
 221
 222         /**
 223          * Checks whether tasks are left including idle task
 224          *
 225          * @return      $tasksLeft      Whether there are tasks left to handle
 226          */
 227         public function hasTasksLeft () {
 228                 // Do we have tasks there?
 229                 $tasksLeft = (($this->getListInstance() instanceof Listable) && ($this->getListInstance()->count() > 0));
 230
 231                 // Return result
 232                 return $tasksLeft;
 233         }
 234
 235         /**
 236          * Handles all tasks by checking if they should startup or if it is their
 237          * turn to run. You should use this method in a while() loop in conjuntion
 238          * with hasTasksLeft() so you can e.g. shutdown by adding a ShutdownTask
 239          * which will attempt to remove all tasks from the task handler.
 240          *
 241          * @return      void
 242          */
 243         public function handleTasks () {
 244                 // Should we rewind?
 245                 if (!$this->getListInstance()->getIterator()->valid()) {
 246                         // Rewind to the beginning for next loop
 247                         $this->getListInstance()->getIterator()->rewind();
 248                 } // END - if
 249
 250                 // Try to execute the task
 251                 $this->executeCurrentTask();
 252
 253                 // Go to next entry
 254                 $this->getListInstance()->getIterator()->next();
 255         }
 256
 257         /**
 258          * Shuts down all tasks and the task handler itself. This method should be
 259          * called from a corresponding filter class.
 260          *
 261          * @return      void
 262          */
 263         public function doShutdown () {
 264                 // Always rewind to the beginning for next loop
 265                 $this->getListInstance()->getIterator()->rewind();
 266
 267                 // Debug message
 268                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Shutting down all ' . $this->getListInstance()->count() . ' tasks...');
 269
 270                 // Remember all tasks that has been shutdown for removal
 271                 $tasks = array();
 272
 273                 // Instance a visitor
 274                 $this->setVisitorInstance(ObjectFactory::createObjectByConfiguredName('shutdown_task_visitor_class'));
 275
 276                 // Shutdown all tasks in once go
 277                 while ($this->getListInstance()->getIterator()->valid()) {
 278                         // Get current entry
 279                         $currentTask = $this->getListInstance()->getIterator()->current();
 280
 281                         // Output debug message
 282                         self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Shutting down task ' . $currentTask['id'] . ' (taskInstance=' . $currentTask['task_instance']->__toString() . ') ...');
 283
 284                         // Shutdown the task
 285                         $currentTask['task_instance']->accept($this->getVisitorInstance());
 286
 287                         // Remember this task
 288                         $tasks[] = $currentTask;
 289
 290                         // Advance to next one
 291                         $this->getListInstance()->getIterator()->next();
 292                 } // END - while
 293
 294                 // Debug message
 295                 self::createDebugInstance(__CLASS__)->debugOutput('TASK-HANDLER[' . __LINE__ . ']: Shutdown of all tasks completed.');
 296
 297                 // Remove all tasks
 298                 foreach ($tasks as $entry) {
 299                         $this->unregisterTask($entry);
 300                 } // END - foreach
 301         }
 302 }
 303
 304 // [EOF]
 305 ?>