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\Object\ObjectFactory;
   8 use Org\Mxchange\CoreFramework\Generic\FrameworkInterface;
   9 use Org\Mxchange\CoreFramework\Loader\NoClassException;
  10 use Org\Mxchange\CoreFramework\Object\BaseFrameworkSystem;
  11 use Org\Mxchange\CoreFramework\Utils\Strings\StringUtils;
  12
  13 // Import SPL stuff
  14 use \InvalidArgumentException;
  15
  16 /**
  17  * The general feature management class. No instance is needed as this class
  18  * has only public methods that are static.
  19  *
  20  * @author              Roland Haeder <webmaster@ship-simu.org>
  21  * @version             0.0.0
  22  * @copyright   Copyright (c) 2007, 2008 Roland Haeder, 2009 - 2022 Core Developer Team
  23  * @license             GNU GPL 3.0 or any newer version
  24  * @link                http://www.ship-simu.org
  25  *
  26  * This program is free software: you can redistribute it and/or modify
  27  * it under the terms of the GNU General Public License as published by
  28  * the Free Software Foundation, either version 3 of the License, or
  29  * (at your option) any later version.
  30  *
  31  * This program is distributed in the hope that it will be useful,
  32  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  33  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  34  * GNU General Public License for more details.
  35  *
  36  * You should have received a copy of the GNU General Public License
  37  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  38  */
  39 class FrameworkFeature extends BaseFrameworkSystem {
  40         // Exception code constants
  41         const EXCEPTION_FEATURE_METHOD_NOT_CALLABLE = 0x400;
  42
  43         /**
  44          * "Cache" for enabled, available feature instances
  45          *
  46          * A typical available entry looks like this:
  47          *
  48          * array(
  49          *     'is_enabled'   => true,
  50          *     'is_available' => true,
  51          *     'instance'     => SomeFeature Object
  52          * )
  53          *
  54          * And a typical disabled entry looks like this:
  55          *
  56          * array(
  57          *     'is_enabled'   => false,
  58          *     'is_available' => false,
  59          *     'instance'     => NULL
  60          * )
  61          */
  62         private static $enabledFeatures = [];
  63
  64         /**
  65          * Protected constructor
  66          *
  67          * @return      void
  68          */
  69         private function __construct () {
  70                 // Call parent constructor
  71                 parent::__construct(__CLASS__);
  72         }
  73
  74         /**
  75          * Checks whether the given feature is enabled in configuration. The user
  76          * shall be able to disable features, even when they *could* be available.
  77          *
  78          * @param       $featureName    Name of the feature to be checked
  79          * @return      $isEnabled              Whether the given feature is enabled
  80          * @throws      InvalidArgumentException        If a parameter is invalid
  81          */
  82         public static function isFeatureEnabled (string $featureName) {
  83                 // Check parameter
  84                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s - CALLED!', $featureName));
  85                 if (empty($featureName)) {
  86                         // Throw IAE
  87                         throw new InvalidArgumentException('Parameter "featureName" is empty', FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
  88                 }
  89
  90                 // Is the cache set?
  91                 if (!isset(self::$enabledFeatures[$featureName]['is_enabled'])) {
  92                         // Generate config key
  93                         $configKey = sprintf('enable_feature_%s', $featureName);
  94
  95                         // Check configuration
  96                         self::$enabledFeatures[$featureName]['is_enabled'] = (FrameworkBootstrap::getConfigurationInstance()->getConfigEntry($configKey) === 'Y');
  97                 }
  98
  99                 // Return "cached" status
 100                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: is_enabled[%s]=%d - EXIT!', $featureName, intval(self::$enabledFeatures[$featureName]['is_enabled'])));
 101                 return self::$enabledFeatures[$featureName]['is_enabled'];
 102         }
 103
 104         /**
 105          * Checks whether the given feature is enabled and available. It may be
 106          * enabled by the user, but is not available due to e.g. a missing PECL
 107          * extension or whatever is needed to have this feature available. If you
 108          * don't write a pre filters for checking PHP requirements, this is the
 109          * method you want to use.
 110          *
 111          * @param       $featureName    Name of the feature to be checked on availability
 112          * @return      $isAvailable    Whether the given feature is available
 113          * @throws      InvalidArgumentException        If a parameter is invalid
 114          */
 115         public static function isFeatureAvailable (string $featureName) {
 116                 // Check parameter
 117                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s - CALLED!', $featureName));
 118                 if (empty($featureName)) {
 119                         // Throw IAE
 120                         throw new InvalidArgumentException('Parameter "featureName" is empty', FrameworkInterface::EXCEPTION_INVALID_ARGUMENT);
 121                 }
 122
 123                 // Is the cache set?
 124                 if (!isset(self::$enabledFeatures[$featureName]['is_available'])) {
 125                         // Default is not available
 126                         self::$enabledFeatures[$featureName]['is_available'] = false;
 127                         self::$enabledFeatures[$featureName]['instance']     = NULL;
 128
 129                         // Is the feature enabled?
 130                         if (!self::isFeatureEnabled($featureName)) {
 131                                 // Then it can't be available
 132                                 self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: Feature "%s"is not enabled.', $featureName));
 133                                 return false;
 134                         }
 135
 136                         // Create config key (for feature class lookup)
 137                         $configKey = sprintf('feature_%s_class', $featureName);
 138
 139                         // Now try to get the instance
 140                         //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: configKey=%s', $configKey));
 141                         try {
 142                                 // Try to get an instance
 143                                 self::$enabledFeatures[$featureName]['instance'] = ObjectFactory::createObjectByConfiguredName($configKey);
 144
 145                                 // Now let the feature test itself's availability
 146                                 self::$enabledFeatures[$featureName]['is_available'] = self::$enabledFeatures[$featureName]['instance']->isFeatureAvailable();
 147                         } catch (NoClassException $e) {
 148                                 // Feature class not found
 149                                 self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: Feature "%s"is not available due to missing feature class. Disabling feature ...', $featureName));
 150                         }
 151                 }
 152
 153                 // Return "cached" status
 154                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s,isAvailable=%d - EXIT!', $featureName, intval(self::$enabledFeatures[$featureName]['is_available'])));
 155                 return self::$enabledFeatures[$featureName]['is_available'];
 156         }
 157
 158         /**
 159          * Calls the feature's method and handles some arguments (if not given,
 160          * NULL) to it. Any returned value is being forwarded to the caller, even
 161          * when the doc-tag says 'void' as returned value.
 162          *
 163          * @param       $featureName    Name of the feature, it must be available at this point
 164          * @param       $featureMethod  Method name of the feature's class
 165          * @param       $args                   Any arguments that should be handled over
 166          * @return      $return                 Anything the feature's method has returned
 167          * @throws      FeatureMethodNotCallableException       If the requested method cannot be called
 168          */
 169         public static function callFeature ($featureName, $featureMethod, array $args = NULL) {
 170                 /*
 171                  * Please make sure that isFeatureAvailable() has been called and it has
 172                  * returned true before calling this method.
 173                  */
 174                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: featureName=%s,featureMethod=%s,args[]=%s - CALLED!', $featureName, $featureMethod, gettype($args)));
 175                 assert(self::isFeatureAvailable($featureName));
 176
 177                 // Array for call-back
 178                 $callable = array(
 179                         self::$enabledFeatures[$featureName]['instance'],
 180                         sprintf('featureMethod%s', StringUtils::convertToClassName($featureMethod))
 181                 );
 182
 183                 // So is the feature's method callable?
 184                 if (!is_callable($callable)) {
 185                         // Not callable method requested
 186                         throw new FeatureMethodNotCallableException(array(self::$enabledFeatures[$featureName]['instance'], $featureMethod), self::EXCEPTION_FEATURE_METHOD_NOT_CALLABLE);
 187                 }
 188
 189                 // Then call it
 190                 $return = call_user_func_array($callable, $args);
 191
 192                 // Return any returned value
 193                 //* NOISY-DEBUG: */ self::createDebugInstance(__CLASS__, __LINE__)->debugOutput(sprintf('FRAMEWORK-FEATURE: return[]=%s - EXIT!', gettype($return)));
 194                 return $return;
 195         }
 196
 197 }