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