| 1 |  |  | <?php | 
            
                                                                                                            
                            
            
                                    
            
            
                | 2 |  |  | /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 3 |  |  |  * Go! AOP framework | 
            
                                                                                                            
                            
            
                                    
            
            
                | 4 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 5 |  |  |  * @copyright Copyright 2015, Lisachenko Alexander <[email protected]> | 
            
                                                                                                            
                            
            
                                    
            
            
                | 6 |  |  |  * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 7 |  |  |  * This source file is subject to the license that is bundled | 
            
                                                                                                            
                            
            
                                    
            
            
                | 8 |  |  |  * with this source code in the file LICENSE. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 9 |  |  |  */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 10 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 11 |  |  | namespace Go\Symfony\GoAopBundle\DependencyInjection; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 12 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 13 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 14 |  |  | use Symfony\Component\Config\FileLocator; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 15 |  |  | use Symfony\Component\DependencyInjection\ContainerBuilder; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 16 |  |  | use Symfony\Component\HttpKernel\DependencyInjection\Extension; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 17 |  |  | use Symfony\Component\DependencyInjection\Loader\XmlFileLoader; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 18 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 19 |  |  | class GoAopExtension extends Extension | 
            
                                                                                                            
                            
            
                                    
            
            
                | 20 |  |  | { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 21 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 22 |  |  |      * {@inheritdoc} | 
            
                                                                                                            
                            
            
                                    
            
            
                | 23 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 24 |  |  |     public function getNamespace() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 25 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 26 |  |  |         return 'http://go.aopphp.com/xsd-schema/go-aop-bundle'; | 
            
                                                                                                            
                            
            
                                    
            
            
                | 27 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 28 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 29 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 30 |  |  |      * {@inheritdoc} | 
            
                                                                                                            
                            
            
                                    
            
            
                | 31 |  |  |      */ | 
            
                                                                                                            
                            
            
                                    
            
            
                | 32 |  |  |     public function getXsdValidationBasePath() | 
            
                                                                                                            
                            
            
                                    
            
            
                | 33 |  |  |     { | 
            
                                                                                                            
                            
            
                                    
            
            
                | 34 |  |  |         return __DIR__ . '/../Resources/config/schema'; | 
                            
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                | 35 |  |  |     } | 
            
                                                                                                            
                            
            
                                    
            
            
                | 36 |  |  |  | 
            
                                                                                                            
                            
            
                                    
            
            
                | 37 |  |  |     /** | 
            
                                                                                                            
                            
            
                                    
            
            
                | 38 |  |  |      * Loads a specific configuration. | 
            
                                                                                                            
                            
            
                                    
            
            
                | 39 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 40 |  |  |      * @param array $config An array of configuration values | 
            
                                                                                                            
                            
            
                                    
            
            
                | 41 |  |  |      * @param ContainerBuilder $container A ContainerBuilder instance | 
            
                                                                                                            
                            
            
                                    
            
            
                | 42 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 43 |  |  |      * @throws \InvalidArgumentException When provided tag is not defined in this extension | 
            
                                                                                                            
                            
            
                                    
            
            
                | 44 |  |  |      * | 
            
                                                                                                            
                            
            
                                    
            
            
                | 45 |  |  |      * @api | 
            
                                                                                                            
                                                                
            
                                    
            
            
                | 46 |  |  |      */ | 
            
                                                        
            
                                    
            
            
                | 47 |  |  |     public function load(array $config, ContainerBuilder $container) | 
            
                                                        
            
                                    
            
            
                | 48 |  |  |     { | 
            
                                                        
            
                                    
            
            
                | 49 |  |  |         $configurator = new Configuration(); | 
            
                                                        
            
                                    
            
            
                | 50 |  |  |         $config       = $this->processConfiguration($configurator, $config); | 
            
                                                        
            
                                    
            
            
                | 51 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 52 |  |  |         $normalizedOptions = array(); | 
            
                                                        
            
                                    
            
            
                | 53 |  |  |         foreach ($config['options'] as $optionKey => $value) { | 
            
                                                        
            
                                    
            
            
                | 54 |  |  |             // this will convert 'under_scores' into 'underScores' | 
            
                                                        
            
                                    
            
            
                | 55 |  |  |             $optionKey = lcfirst(str_replace(' ', '', ucwords(str_replace('_', ' ', $optionKey)))); | 
            
                                                        
            
                                    
            
            
                | 56 |  |  |             $normalizedOptions[$optionKey] = $value; | 
            
                                                        
            
                                    
            
            
                | 57 |  |  |         } | 
            
                                                        
            
                                    
            
            
                | 58 |  |  |         $container->setParameter('goaop.options', $normalizedOptions); | 
            
                                                        
            
                                    
            
            
                | 59 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 60 |  |  |         $loader = new XmlFileLoader($container, new FileLocator(__DIR__ . '/../Resources/config')); | 
            
                                                        
            
                                    
            
            
                | 61 |  |  |         $loader->load('services.xml'); | 
            
                                                        
            
                                    
            
            
                | 62 |  |  |         $loader->load('commands.xml'); | 
            
                                                        
            
                                    
            
            
                | 63 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 64 |  |  |         if ($config['cache_warmer']) { | 
            
                                                        
            
                                    
            
            
                | 65 |  |  |             $definition = $container->getDefinition('goaop.cache.warmer'); | 
            
                                                        
            
                                    
            
            
                | 66 |  |  |             $definition->addTag('kernel.cache_warmer'); | 
            
                                                        
            
                                    
            
            
                | 67 |  |  |         } | 
            
                                                        
            
                                    
            
            
                | 68 |  |  |  | 
            
                                                        
            
                                    
            
            
                | 69 |  |  |         if ($config['doctrine_support']) { | 
            
                                                        
            
                                    
            
            
                | 70 |  |  |             $container | 
            
                                                        
            
                                    
            
            
                | 71 |  |  |                 ->getDefinition('goaop.bridge.doctrine.metadata_load_interceptor') | 
            
                                                        
            
                                    
            
            
                | 72 |  |  |                 ->addTag('doctrine.event_subscriber'); | 
            
                                                        
            
                                    
            
            
                | 73 |  |  |         } | 
            
                                                        
            
                                    
            
            
                | 74 |  |  |     } | 
            
                                                        
            
                                    
            
            
                | 75 |  |  | } | 
            
                                                        
            
                                    
            
            
                | 76 |  |  |  | 
            
                        
If you return a value from a function or method, it should be a sub-type of the type that is given by the parent type f.e. an interface, or abstract method. This is more formally defined by the Lizkov substitution principle, and guarantees that classes that depend on the parent type can use any instance of a child type interchangably. This principle also belongs to the SOLID principles for object oriented design.
Let’s take a look at an example:
Our function
my_functionexpects aPostobject, and outputs the author of the post. The base classPostreturns a simple string and outputting a simple string will work just fine. However, the child classBlogPostwhich is a sub-type ofPostinstead decided to return anobject, and is therefore violating the SOLID principles. If aBlogPostwere passed tomy_function, PHP would not complain, but ultimately fail when executing thestrtouppercall in its body.