Case study Classic MVC with separated front-end Piotr Lewandowski @piotlr 

Back-end Java 8 Spring 4 + Spring boot Apache POI Thymeleaf Gradle Front-end bootstrap require.js npm bower gulp 

Java 8 

Java 7 way Java 8 way List humans = ... Collections.sort(humans, new Comparator() { @Override public int compare(Human h1, Human h2) return h1.getName().compareTo(h2.getName()); } } List humans = ... Collections.sort(humans, (Human h1, Human h2) ­> { h1.getName().compareTo(h2.getName()) }); 

Streams API List persons = ...; Stream tenPersonsOver18 = persons.stream() .filter(p ­> p.getAge() > 18) .limit(10); boolean isEmptyRow = csvRowEntries.stream() .allMatch(str ­> str.isEmpty()); if (isEmptyRow) { return null; } 

Streams API // set id, location employees.stream() .filter(e ­> e.getId().equals(id)) .findFirst() .ifPresent(e ­> { e.setLocation(location); }); public List getErrors() { return parseErrors.stream() .map(pe ­> pe.getMessage()) .collect(Collectors.toList()); } 

Streams in tests // arrange // ... List divergenceReport; List missingEmployees; // act divergenceReport = service.getDivergenceReport(); missingEmployees = divergenceReport.stream() .map(MissingEmployee::getId) .collect(Collectors.toList()); // assert assertThat(missingEmployees.contains("Robert Smith"), is(true)); 

Confusions Closure Custom lambdas 

Closures int i = 0; persons.forEach(person ­> { if ( person == null) { i++; // Error: Variable must be final or effective final } ... }); 

Custom lamdas public class Main { public static void runCalc( ??? calc) { // ??? } public static void main(String[] args) { BigDecimal a = new BigDecimal(); runCalc(a ­> a.multiply(a)); } } 

Custom lambdas Scala def runCalc(calc: (BigInt => BigInt)) { // ??? } Java interface MyCalcLambda { BigInteger run(BigInteger input); } public static void runCalc(MyCalcLambda calc) { // ??? } public static void main(String[] args) { runCalc(a ­> a.multiply(a)); } 

Runing custom lambdas Scala def runCalc(calc: (BigInt => BigInt)) { System.out.println(calc(10)) } Java public static void runCalc(MyCalcLambda calc) { System.out.println(calc(BigInteger.TEN)); } 

Spring 4 with Spring boot Long story short 

Configuration public class ServletInitializer extends SpringBootServletInitializer { @Override protected SpringApplicationBuilder configure(SpringApplicationBuilder application) { return application.sources(Application.class); } } @Configuration @ComponentScan @EnableAutoConfiguration public class Application extends WebMvcConfigurerAdapter { public static void main(String[] args) { SpringApplication.run(Application.class, args); } } 

start.spring.io 

Thymeleaf 

Primitive Maps Lists i18n config constans loops conditionals formats modules What can we put? What can we do? 

Name Cost Hours Project ID 1000.0 353 

HTML5 way /*/­­> /*/­­> ... ... ... 

Gradle 

Worries Do I need to learn groovy? Can I still use my dependencies? If my IDE supports gradle? 

gradle hello world apply plugin: 'java' sourceCompatibility = 1.8 jar { baseName = 'demo' version = '0.0.1­SNAPSHOT' } repositories { mavenCentral() } dependencies { compile("org.springframework.boot:spring­boot­starter­web") compile("org.springframework.boot:spring­boot­starter­thymeleaf") testCompile("org.springframework.boot:spring­boot­starter­test") } 

repositories { maven { credentials { username 'user' password 'password' } url "http://10.10.0.1/your­maven­repo" } } Custom repostiories 

So why gradle? Clean Efficient Easily expandable with plugins 

Front-end 

Building front-end Modularity Dependency managment Production-ready Tests 

Cons Many, many tools Frequent changes Pros Many, many tools Frequent changes 

Front-end structure src ├── css ├── js dist ├── lib ├── css ├── js gulpfile.js bower.json package.json 

Build tools demo 

Building process What are doing when we type `gradle build` 

gradle build 1. Compille front-end 1. Download tools with NPM 2. Download dependencies with bower 3. Build front-end with gulp 4. Pack into JAR 2. Compile the rest with front-end as a dependency 

Questions 

Thanks