Retour à la simplicité. Vincent

Transcription

1 Retour à la simplicité Vincent

2 Un sentiment de déja-vu? Vous démarrez un projet avec une dizaine de librairies et frameworks Le bagage à trainer est lourd et vous coute cher Un des frameworks se met en travers de votre chemin Vous vous sentez prisonnier d un des frameworks Un framework vous surprend par sa «magie»

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5 Le point de départ Spring et Spring MVC Velocity et SiteMesh Hibernate, JPA Hibernate Validator Maven 53 jars externes!

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7 Le défi Uniquement des outils simples DIYS (Do It Yourself Simply) Assemblage, déploiement et configuration faciles XML Annotations Framework (Web, ORM, DI)

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11 Build define 'petstore', [..] do define 'domain' do compile.with test.with HAMCREST package :jar end define 'persistence' do compile.with project(:domain) test.with HAMCREST, :flyway, :mysql, NO_LOG, [...] package :jar end define 'webapp' domain compile.with :simpleframework, :jmustache, [...] test.with HAMCREST, :antlr_runtime, :cssselectors, :hamcrest_dom, [...] test.with transitive(artifacts(:nekohtml, :htmlunit, :jmock_legacy)) package :jar end

12 Injection de dépendances AttachmentStorage attachments = new FileSystemPhotoStore("/photos"); Connection connection = new ConnectionReference(request).get(); Transactor transactor = new JDBCTransactor(connection); ProductCatalog products = new ProductsDatabase(connection); ItemInventory items = new ItemsDatabase(connection); OrderBook orders = new OrdersDatabase(connection); ProcurementRequestHandler procurement = new PurchasingAgent(products, items, transactor) OrderNumberSequence ordernumbers = new OrderNumberDatabaseSequence(connection); Cashier cashier = new Cashier(orderNumbers, orders, transactor); Messages messages = new BundledMessages(ResourceBundle.getBundle("ValidationMessages"))

13 Routing Router router = Router.draw(new DynamicRoutes() {{ get("/products").to(new ListProducts(products, attachments, pages.products())); post("/products").to(new CreateProduct(procurement)); get("/products/:product/items").to(new ListItems(items, pages.items())); post("/products/:product/items").to(new CreateItem(procurement)); get("/cart").to(new ShowCart(cashier, pages.cart())); post("/cart").to(new CreateCartItem(cashier)); get("/orders/new").to(new Checkout(cashier, pages.checkout())); get("/orders/:number").to(new ShowOrder(orders, pages.order())); post("/orders").to(new PlaceOrder(cashier)); delete("/logout").to(new Logout()); map("/").to(new StaticPage(pages.home())); );

14 MVC public class ShowOrder implements Application { private final OrderBook orderbook; private final Page orderpage; public ShowOrder(OrderBook orderbook, Page orderpage) { this.orderbook = orderbook; this.orderpage = orderpage; public void handle(request request, Response response) throws Exception { String number = request.parameter("number"); Order order = orderbook.find(new OrderNumber(number)); orderpage.render(response, context().with("order", order).asmap());

15 Accès aux données public class OrdersDatabase implements OrderBook { private final Connection connection; [...] public OrdersDatabase(Connection connection) { this.connection = connection; private List<LineItem> findlineitemsof(order order) { return Select.from(lineItems). where("order_id =?", idof(order).get()). orderby("order_line"). list(connection); private Order findorder(ordernumber ordernumber) { return Select.from(orders, "_order"). leftjoin(payments, "payment", "_order.payment_id = payment.id"). where("_order.number =?", ordernumber). first(connection);

16 Transactions public class Cashier implements SalesAssistant { [...] public OrderNumber placeorder(paymentmethod paymentmethod) throws Exception { Ensure.valid(paymentMethod); QueryUnitOfWork<OrderNumber> order = new QueryUnitOfWork<OrderNumber>() { public OrderNumber query() throws Exception { OrderNumber nextnumber = ordernumbersequence.nextordernumber(); final Order order = new Order(nextNumber); order.additemsfrom(cart); order.pay(paymentmethod); orderbook.record(order); cart.clear(); return nextnumber; ; return transactor.performquery(order);

17 Contraintes de validité public class CreditCardDetails extends PaymentMethod implements Serializable { private final CreditCardType cardtype; private final Constraint<String> cardnumber; private final NotNull<String> cardexpirydate; private final Valid<Address> billingaddress; public CreditCardDetails(CreditCardType type, String number, String expirydate, Address billingaddress) { this.cardtype = type; this.cardnumber = Validates.both(Validates.notEmpty(number), Validates.correctnessOf(type, number)); this.cardexpirydate = Validates.notNull(expiryDate); this.billingaddress = Validates.validityOf(billingAddress);

18 Validation public class Validator { public <T> Set<ConstraintViolation<?>> validate(t target) { Valid<T> valid = Validates.validityOf(target); valid.disablerootviolation(); ViolationsReport report = new ViolationsReport(); valid.check(path.root(target), report); return report.violations(); [...]

19 Formulaires public class PaymentForm extends Form { public static PaymentForm parse(request request) { return new PaymentForm(new CreditCardDetails( valueof(request.parameter("card-type")), request.parameter("card-number"), request.parameter("expiry-date"), new Address(request.parameter("first-name"), request.parameter("last-name"), request.parameter(" ")))); private final Valid<CreditCardDetails> paymentdetails; public PaymentForm(CreditCardDetails paymentdetails) { this.paymentdetails = Validates.validityOf(paymentDetails); public CreditCardType cardtype() { return paymentdetails().getcardtype(); public CreditCardDetails paymentdetails() { return paymentdetails.get();

20 Toutefois Pas très «entreprise» Pas à la portée de toutes les équipes? Pas à toutes les sauces Pas sans risque?

21 Leçons apprises Éviter la tentation des frameworks Utiliser des outils simples, légers et spécialisés Construire mes propres outils S inspirer des meilleures idées; réécrire le code simplement Spécialiser plutôt que de généraliser

22 Références Nouvelle version : Ancienne version : Data Mapping :