Symfony World - Symfony components and design patterns

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Symfony Components and DesignPatterns

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Design patterns?

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Why should youcare?

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Communication

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Communication Reduced amount ofcode in one chunk

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Communication Reduced amount ofcode in one chunk Increased cohesion and reduced coupling

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Communication Reduced amount ofcode in one chunk Increased cohesion and reduced coupling Extendibility

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Communication Reduced amount ofcode in one chunk Increased cohesion and reduced coupling Extendibility SOLID

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Increase code quality

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Can we measureit?

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Avg. Logic Linesof Code

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Avg. Logic Linesof Code LLoC

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Avg. Logic Linesof Code LLoC Amount of classes

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Avg. Logic Linesof Code LLoC Amount of classes AoC

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Avg. Logic Linesof Code LLoC Amount of classes AoC Avg. Cyclomatic Complexity

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Avg. Logic Linesof Code LLoC Amount of classes AoC Avg. Cyclomatic Complexity ACC

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Let’s see thecode

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Sample Project

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final class CheckoutController { privatearray $repository = []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } // Apply taxation /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CheckoutController { privatearray $repository = []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } // Apply taxation /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; }

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{ // Fetch objectfrom repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct( $options[‘product'], $options[‘type'], $options[‘quantity'], $options[‘price'] ); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } // Apply taxation /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } // Save into repository

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private array $repository= []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } // Apply taxation /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } // Save into repository $this->repository[$options['cart_id']] = $cart;

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Avg. Logic Linesof Code 40 Amount of classes 1 Avg. Cyclomatic Complexity 8

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LLoC AoC ACC Sampleproject 40 1 8

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Single responsibility principle Openclose principle Liskov substitution principle Interface segregation principle Dependency inversion principle

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Composition

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Preparation

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$cart = newCart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } // Apply taxation /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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private array $repository= []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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private function applyTaxation(Cart$cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } } private function applyPromotion(Cart $cart): void { if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } }

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private array $repository= []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CheckoutController { privatearray $repository = []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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private function processOrder(Cart$cart): void { // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); }

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final class CheckoutController { privatearray $repository = []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } private function applyTaxation(Cart $cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } } private function applyPromotion(Cart $cart): void { if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } } /** * @param Cart $cart */ private function processOrder(Cart $cart): void { // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); } }

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Extraction

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final class CheckoutController { privatearray $repository = []; public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CompositeOrderProcessorimplements OrderProcessor { public function processOrder(Cart $cart): void { // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); } private function applyTaxation(Cart $cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } } private function applyPromotion(Cart $cart): void { if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } } }

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LLoC AoC ACC Sampleproject 40 1 8 Extracted processor 61 2 4.5

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final class OrderTaxationProcessorimplements OrderProcessor { public function processOrder(Cart $cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } } }

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final class CompositeOrderProcessorimplements OrderProcessor { public function processOrder(Cart $cart): void { // Apply promotion $this->applyPromotion($cart); // Apply taxation $this->applyTaxation($cart); } private function applyPromotion(Cart $cart): void { if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } } }

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final class OrderPromotionProcessorimplements OrderProcessor { public function processOrder(Cart $cart): void { if ($cart->getPrice() >= 1000) { $cart->applyPercentageDiscount(0.1); } } }

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final class CompositeOrderProcessorimplements OrderProcessor { private OrderPromotionProcessor $orderPromotionProcessor; private OrderTaxationProcessor $orderTaxationProcessor; public function __construct( OrderPromotionProcessor $orderPromotionProcessor, OrderTaxationProcessor $orderTaxationProcessor ) { $this->orderPromotionProcessor = $orderPromotionProcessor; $this->orderTaxationProcessor = $orderTaxationProcessor; } public function processOrder(Cart $cart): void { // Apply promotion $this->orderPromotionProcessor->processOrder($cart); // Apply taxation $this->orderTaxationProcessor->processOrder($cart); } }

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LLoC AoC ACC Sampleproject 40 1 8 Extracted processor 61 2 4.5 Separated processors 76 4 2.75

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final class CompositeOrderProcessorimplements OrderProcessor { private OrderPromotionProcessor $orderPromotionProcessor; private OrderTaxationProcessor $orderTaxationProcessor; public function __construct( OrderPromotionProcessor $orderPromotionProcessor, OrderTaxationProcessor $orderTaxationProcessor ) { $this->orderPromotionProcessor = $orderPromotionProcessor; $this->orderTaxationProcessor = $orderTaxationProcessor; } public function processOrder(Cart $cart): void { // Apply promotion $this->orderPromotionProcessor->processOrder($cart); // Apply taxation $this->orderTaxationProcessor->processOrder($cart); } }

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final class CompositeOrderProcessorimplements OrderProcessor { private iterable $orderProcessors; public function __construct( OrderPromotionProcessor $orderPromotionProcessor, OrderTaxationProcessor $orderTaxationProcessor ) { $this->orderProcessors = [ $orderPromotionProcessor, $orderTaxationProcessor ]; } public function processOrder(Cart $cart): void { foreach ($this->orderProcessors as $orderProcessor) { $orderProcessor->processOrder($cart); } } }

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final class CompositeOrderProcessorimplements OrderProcessor { private iterable $orderProcessors; public function __construct(iterable $orderProcessors) { $this->orderProcessors = $orderProcessors; } public function processOrder(Cart $cart): void { foreach ($this->orderProcessors as $orderProcessor) { $orderProcessor->processOrder($cart); } } }

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final class CompositeOrderProcessorimplements OrderProcessor { private iterable $orderProcessors; public function __construct(iterable $orderProcessors) { $this->orderProcessors = $orderProcessors; } public function processOrder(Cart $cart): void { foreach ($this->orderProcessors as $orderProcessor) { $orderProcessor->processOrder($cart); } } }

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SymfonyDesignPatternsProcessorOrderProcessor: class: 'SymfonyDesignPatternsProcessorCompositeOrderProcessor' arguments: - [ '@SymfonyDesignPatternsProcessorOrderPromotionProcessor', '@SymfonyDesignPatternsProcessorOrderTaxationProcessor' ]

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Can Symfony helpus with it?

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SymfonyDesignPatternsProcessorOrderProcessor: class: 'SymfonyDesignPatternsProcessorCompositeOrderProcessor' arguments: - !tagged_iteratorapp.order_processor

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SymfonyDesignPatternsProcessorOrderProcessor: class: 'SymfonyDesignPatternsProcessorCompositeOrderProcessor' arguments: - !tagged_iteratorapp.order_processor

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SymfonyDesignPatternsProcessorOrderPromotionProcessor: tags: - app.order_processor SymfonyDesignPatternsProcessorOrderTaxationProcessor: tags: - app.order_processor

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LLoC AoC ACC Sampleproject 40 1 8 Extracted processor 61 2 4.5 Separated processors 76 4 2.75 Composite iteration 73 4 3

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LLoC AoC ACC Sampleproject 40 1 8 Composite iteration 73 4 3

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Strategy

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final class OrderTaxationProcessorimplements OrderProcessor { private TaxationStrategyDelegator $taxationStrategy; public function __construct(TaxationStrategyDelegator $taxationStrategy) { $this->taxationStrategy = $taxationStrategy; } public function processOrder(Cart $cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { $this->taxationStrategy->processTaxation($item); } } }

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final class OrderTaxationProcessorimplements OrderProcessor { private TaxationStrategyDelegator $taxationStrategy; public function __construct(TaxationStrategyDelegator $taxationStrategy) { $this->taxationStrategy = $taxationStrategy; } public function processOrder(Cart $cart): void { /** @var CartItem $item */ foreach ($cart->getItems() as $item) { $this->taxationStrategy->processTaxation($item); } } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { public function processTaxation(CartItem $item): void { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { public function processTaxation(CartItem $item): void { if ('shirt' === $item->getType()) { $item->setTaxationPercentage(0.23); } if ('book' === $item->getType()) { $item->setTaxationPercentage(0.08); } } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { private ShirtTaxationStrategy $shirtTaxationStrategy; private BookTaxationStrategy $bookTaxationStrategy; public function __construct( ShirtTaxationStrategy $shirtTaxationStrategy, BookTaxationStrategy $bookTaxationStrategy ) { $this->shirtTaxationStrategy = $shirtTaxationStrategy; $this->bookTaxationStrategy = $bookTaxationStrategy; } public function processTaxation(CartItem $item): void { if ('shirt' === $item->getType()) { $this->shirtTaxationStrategy->processTaxation($item); } if ('book' === $item->getType()) { $this->bookTaxationStrategy->processTaxation($item); } } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { private array $indexedTaxationStrategies; public function __construct( ShirtTaxationStrategy $shirtTaxationStrategy, BookTaxationStrategy $bookTaxationStrategy ) { $this->indexedTaxationStrategies = [ 'shirt' => $shirtTaxationStrategy, 'book' => $bookTaxationStrategy, ]; } public function processTaxation(CartItem $item): void { $this->indexedTaxationStrategies[$item->getType()]->processTaxation($item); } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { private ServiceLocator $taxationStrategies; public function __construct(ServiceLocator $taxationStrategies) { $this->taxationStrategies = $taxationStrategies; } public function processTaxation(CartItem $item): void { $this->taxationStrategies->get($item->getType())->processTaxation($item); } }

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final class TaxationStrategyDelegatorimplements TaxationStrategy { private ServiceLocator $taxationStrategies; public function __construct(ServiceLocator $taxationStrategies) { $this->taxationStrategies = $taxationStrategies; } public function processTaxation(CartItem $item): void { $this->taxationStrategies->get($item->getType())->processTaxation($item); } }

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SymfonyDesignPatternsTaxationStrategiesTaxationStrategy: class: 'SymfonyDesignPatternsTaxationStrategiesTaxationStrategyDelegator' arguments: - !tagged_locator{ tag: 'app.taxation_strategies', index_by: 'type' }

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SymfonyDesignPatternsTaxationStrategiesTaxationStrategy: class: 'SymfonyDesignPatternsTaxationStrategiesTaxationStrategyDelegator' arguments: - !tagged_locator{ tag: 'app.taxation_strategies', index_by: 'type' }

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SymfonyDesignPatternsTaxationStrategiesBookTaxationStrategy: tags: - { name:'app.taxation_strategies', type: 'book' } SymfonyDesignPatternsTaxationStrategiesShirtTaxationStrategy: tags: - { name: 'app.taxation_strategies', type: 'shirt' }

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LLoC AoC ACC Sampleproject 40 1 8 Composite iteration 73 4 3 Strategy iteration 102 7 1.86

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Time for smallrefactoring

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final class CheckoutController { privatearray $repository = []; private OrderProcessor $orderProcessor; public function __construct(OrderProcessor $orderProcessor) { $this->orderProcessor = $orderProcessor; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CheckoutController { privatearray $repository = []; private OrderProcessor $orderProcessor; public function __construct(OrderProcessor $orderProcessor) { $this->orderProcessor = $orderProcessor; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository if (isset($this->repository[$options['cart_id']])) { /** @var Cart $cart */ $cart = $this->repository[$options['cart_id']]; } else { $cart = new Cart($options['cart_id']); } // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CheckoutController { privateOrderProcessor $orderProcessor; private CartRepository $cartRepository; public function __construct(OrderProcessor $orderProcessor, CartRepository $cartRepository) { $this->orderProcessor = $orderProcessor; $this->cartRepository = $cartRepository; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($options['cart_id']); // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->cartRepository->save($cart); return $cart; } }

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final class CheckoutController { privateOrderProcessor $orderProcessor; private CartRepository $cartRepository; public function __construct(OrderProcessor $orderProcessor, CartRepository $cartRepository) { $this->orderProcessor = $orderProcessor; $this->cartRepository = $cartRepository; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($options['cart_id']); // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->cartRepository->save($cart); return $cart; } }

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final class InMemoryCartRepositoryimplements CartRepository { private array $repository = []; public function getCart(string $cart_id): Cart { if (isset($this->repository[$cart_id])) { /** @var Cart $cart */ $cart = $this->repository[$cart_id]; } else { $cart = new Cart($cart_id); } return $cart; } }

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public function getCart(string$cart_id): Cart { if (!isset($this->repository[$cart_id])) { $this->repository[$cart_id] = new Cart($cart_id); } /** @var Cart $cart */ return $this->repository[$cart_id]; }

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LLoC AoC ACC Sampleproject 40 1 8 Composite iteration 73 4 3 Strategy iteration 102 7 1.86 Repository extraction 125 8 1.75

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Command

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final class CheckoutController { privatearray $repository = []; private OrderProcessor $orderProcessor; public function __construct(OrderProcessor $orderProcessor) { $this->orderProcessor = $orderProcessor; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($options[‘cart_id']); // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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final class CheckoutController { privatearray $repository = []; private OrderProcessor $orderProcessor; public function __construct(OrderProcessor $orderProcessor) { $this->orderProcessor = $orderProcessor; } public function cartAction(string $operation, array $options): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($options[‘cart_id']); // Perform operation if ('add_to_cart' === $operation) { $cart->addProduct($options['product'], $options['type'], $options['quantity'], $options['price']); } elseif ('remove_from_cart' === $operation) { $cart->removeProduct($options['product']); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->repository[$options['cart_id']] = $cart; return $cart; } }

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public function cartAction(string$operation, array $options): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($options['cart_id']); // Perform operation if ('add_to_cart' === $operation) { $this->messageBus->dispatch(new AddToCart( $options['cart_id'], $options['product'], $options['type'], $options['quantity'], $options['price'] )); } elseif ('remove_from_cart' === $operation) { $this->messageBus->dispatch(new RemoveFromCart( $options['cart_id'], $options['product'], )); } else { throw new InvalidArgumentException('operation not supported'); } $this->orderProcessor->processOrder($cart); // Save into repository $this->cartRepository->save($cart); return $cart; }

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final class AddToCart { privatestring $cartId; private string $product; private string $type; private int $quantity; private int $price; public function __construct(...) { $this->cartId = $cartId; $this->product = $product; $this->type = $type; $this->quantity = $quantity; $this->price = $price; } }

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final class AddToCartHandlerimplements MessageHandlerInterface { private CartRepository $cartRepository; public function __construct(CartRepository $cartRepository) { $this->cartRepository = $cartRepository; } public function __invoke(AddToCart $addToCart) { $cart = $this->cartRepository->getCart($addToCart->getCartId()); $cart->addProduct( $addToCart->getProduct(), $addToCart->getType(), $addToCart->getQuantity(), $addToCart->getPrice() ); $this->cartRepository->save($cart); } }

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public function cartAction(CartIdAwareCommand$operation): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($operation->getCartId()); // Perform operation $this->messageBus->dispatch($operation); $this->orderProcessor->processOrder($cart); // Save into repository $this->cartRepository->save($cart); return $cart; }

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public function cartAction(CartIdAwareCommand$operation): Cart { // Fetch object from repository $cart = $this->cartRepository->getCart($operation->getCartId()); // Perform operation $this->messageBus->dispatch($operation); $this->orderProcessor->processOrder($cart); // Save into repository $this->cartRepository->save($cart); return $cart; }

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LLoC AoC ACC Sampleproject 40 1 8 Composite iteration 73 4 3 Strategy iteration 102 7 1.86 Repository extraction 125 8 1.75 Command iteration 209 12 1.33

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Decorator

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final class AddToCartHandlerimplements MessageHandlerInterface { private CartRepository $cartRepository; public function __construct(CartRepository $cartRepository) { $this->cartRepository = $cartRepository; } public function __invoke(AddToCart $addToCart): Cart { $cart = $this->cartRepository->getCart($addToCart->getCartId()); $cart->addProduct( $addToCart->getProduct(), $addToCart->getType(), $addToCart->getQuantity(), $addToCart->getPrice() ); return $cart; } }

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final class AddToCartHandlerimplements MessageHandlerInterface { private CartRepository $cartRepository; public function __construct(CartRepository $cartRepository) { $this->cartRepository = $cartRepository; } public function __invoke(AddToCart $addToCart): Cart { $cart = $this->cartRepository->getCart($addToCart->getCartId()); $cart->addProduct( $addToCart->getProduct(), $addToCart->getType(), $addToCart->getQuantity(), $addToCart->getPrice() ); return $cart; } }

122.
final class TransactionDecorator { privateMessageHandlerInterface $messageHandler; private CartRepository $cartRepository; public function __construct( MessageHandlerInterface $messageHandler, CartRepository $cartRepository ) { $this->messageHandler = $messageHandler; $this->cartRepository = $cartRepository; } public function __invoke(CartIdAwareCommand $cartIdAwareCommand) { // start transaction $cart = ($this->messageHandler)($cartIdAwareCommand); $this->cartRepository->save($cart); } }

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SymfonyDesignPatternsDecoratorTransactionDecorator: decorates: SymfonyDesignPatternsCommandHandlerAddToCartHandler arguments: - '@.inner'

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LLoC AoC ACC Sampleproject 40 1 8 Composite iteration 73 4 3 Strategy iteration 102 7 1.86 Repository extraction 125 8 1.75 Command iteration 209 12 1.33 Decorator iteration 216 13 1.31

126.
Take offs?

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Trade offs!

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Increased complexity

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Increased complexity Increased testability

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Increased complexity Increased testability Possibilityfor maintenance cost reduction

135.
Symfony may helpyou a lot

136.
@Sylius Thank you! @lukaszchrusciel

Symfony World - Symfony components and design patterns

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