framework/main/classes/feature/class_FrameworkFeature.php

   1 <?php
   2 // Own namespace
   3 namespace Org\Mxchange\CoreFramework\Feature;
   4
   5 // Import framework stuff
   6 use Org\Mxchange\CoreFramework\Bootstrap\FrameworkBootstrap;
   7 use Org\Mxchange\CoreFramework\Factory\ObjectFactory;
   8 use Org\Mxchange\CoreFramework\Loader\NoClassException;
   9 use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
  10 use Org\Mxchange\CoreFramework\Utils\String\StringUtils;
  11
  12 /**
  13  * The general feature management class. No instance is needed as this class
  14  * has only public methods that are static.
  15  *
  16  * @author              Roland Haeder <webmaster@ship-simu.org>
  17  * @version             0.0.0
  18  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2020 Core Developer Team
  19  * @license             GNU GPL 3.0 or any newer version
  20  * @link                http://www.ship-simu.org
  21  *
  22  * This program is free software: you can redistribute it and/or modify
  23  * it under the terms of the GNU General Public License as published by
  24  * the Free Software Foundation, either version 3 of the License, or
  25  * (at your option) any later version.
  26  *
  27  * This program is distributed in the hope that it will be useful,
  28  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  29  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  30  * GNU General Public License for more details.
  31  *
  32  * You should have received a copy of the GNU General Public License
  33  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  34  */
  35 class FrameworkFeature extends BaseFrameworkSystem {
  36         // Exception code constants
  37         const EXCEPTION_FEATURE_METHOD_NOT_CALLABLE = 0x400;
  38
  39         /**
  40          * "Cache" for enabled, available feature instances
  41          *
  42          * A typical available entry looks like this:
  43          *
  44          * array(
  45          *     'is_enabled'   => true,
  46          *     'is_available' => true,
  47          *     'instance'     => SomeFeature Object
  48          * )
  49          *
  50          * And a typical disabled entry looks like this:
  51          *
  52          * array(
  53          *     'is_enabled'   => false,
  54          *     'is_available' => false,
  55          *     'instance'     => NULL
  56          * )
  57          */
  58         private static $enabledFeatures = [];
  59
  60         /**
  61          * Protected constructor
  62          *
  63          * @return      void
  64          */
  65         protected function __construct () {
  66                 // Call parent constructor
  67                 parent::__construct(__CLASS__);
  68         }
  69
  70         /**
  71          * Checks whether the given feature is enabled in configuration. The user
  72          * shall be able to disable features, even when they *could* be available.
  73          *
  74          * @param       $featureName    Name of the feature to be checked
  75          * @return      $isEnabled              Whether the given feature is enabled
  76          */
  77         public static function isFeatureEnabled ($featureName) {
  78                 // Is the cache set?
  79                 if (!isset(self::$enabledFeatures[$featureName]['is_enabled'])) {
  80                         // Generate config key
  81                         $configKey = sprintf('enable_feature_%s', $featureName);
  82
  83                         // Check configuration
  84                         self::$enabledFeatures[$featureName]['is_enabled'] = (FrameworkBootstrap::getConfigurationInstance()->getConfigEntry($configKey) === 'Y');
  85                 } // END - if
  86
  87                 // Return "cached" status
  88                 return self::$enabledFeatures[$featureName]['is_enabled'];
  89         }
  90
  91         /**
  92          * Checks whether the given feature is enabled and available. It may be
  93          * enabled by the user, but is not available due to e.g. a missing PECL
  94          * extension or whatever is needed to have this feature available. If you
  95          * don't write a pre filters for checking PHP requirements, this is the
  96          * method you want to use.
  97          *
  98          * @param       $featureName    Name of the feature to be checked on availability
  99          * @return      $isAvailable    Whether the given feature is available
 100          */
 101         public static function isFeatureAvailable ($featureName) {
 102                 // Is the cache set?
 103                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s - CALLED!', $featureName));
 104                 if (!isset(self::$enabledFeatures[$featureName]['is_available'])) {
 105                         // Default is not available
 106                         self::$enabledFeatures[$featureName]['is_available'] = false;
 107                         self::$enabledFeatures[$featureName]['instance']     = NULL;
 108
 109                         // Is the feature enabled?
 110                         if (!self::isFeatureEnabled($featureName)) {
 111                                 // Then it can't be available
 112                                 self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: Feature "%s"is not enabled.', $featureName));
 113                                 return false;
 114                         } // END - if
 115
 116                         // Create config key (for feature class lookup)
 117                         $configKey = sprintf('feature_%s_class', $featureName);
 118
 119                         // Now try to get the instance
 120                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: configKey=%s', $configKey));
 121                         try {
 122                                 // Try to get an instance
 123                                 self::$enabledFeatures[$featureName]['instance'] = ObjectFactory::createObjectByConfiguredName($configKey);
 124
 125                                 // Now let the feature test itself's availability
 126                                 self::$enabledFeatures[$featureName]['is_available'] = self::$enabledFeatures[$featureName]['instance']->isFeatureAvailable();
 127                         } catch (NoClassException $e) {
 128                                 // Feature class not found
 129                                 self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: Feature "%s"is not available due to missing feature class. Disabling feature ...', $featureName));
 130                         }
 131                 } // END - if
 132
 133                 // Return "cached" status
 134                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s,isAvailable=%d - EXIT!', $featureName, intval(self::$enabledFeatures[$featureName]['is_available'])));
 135                 return self::$enabledFeatures[$featureName]['is_available'];
 136         }
 137
 138         /**
 139          * Calls the feature's method and handles some arguments (if not given,
 140          * NULL) to it. Any returned value is being forwarded to the caller, even
 141          * when the doc-tag says 'void' as returned value.
 142          *
 143          * @param       $featureName    Name of the feature, it must be available at this point
 144          * @param       $featureMethod  Method name of the feature's class
 145          * @param       $args                   Any arguments that should be handled over
 146          * @return      $return                 Anything the feature's method has returned
 147          * @throws      FeatureMethodNotCallableException       If the requested method cannot be called
 148          */
 149         public static function callFeature ($featureName, $featureMethod, array $args = NULL) {
 150                 /*
 151                  * Please make sure that isFeatureAvailable() has been called and it has
 152                  * returned true before calling this method.
 153                  */
 154                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s,featureMethod=%s,args[]=%s - CALLED!', $featureName, $featureMethod, gettype($args)));
 155                 assert(self::isFeatureAvailable($featureName));
 156
 157                 // Array for call-back
 158                 $callable = array(
 159                         self::$enabledFeatures[$featureName]['instance'],
 160                         sprintf('featureMethod%s', StringUtils::convertToClassName($featureMethod))
 161                 );
 162
 163                 // So is the feature's method callable?
 164                 if (!is_callable($callable)) {
 165                         // Not callable method requested
 166                         throw new FeatureMethodNotCallableException(array(self::$enabledFeatures[$featureName]['instance'], $featureMethod), self::EXCEPTION_FEATURE_METHOD_NOT_CALLABLE);
 167                 } // END - if
 168
 169                 // Then call it
 170                 $return = call_user_func_array($callable, $args);
 171
 172                 // Return any returned value
 173                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: return[]=%s - EXIT!', gettype($return)));
 174                 return $return;
 175         }
 176
 177 }