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Groovy best pratices at EWAY
- 1. v Groovy in production ĐàoVăn Hiệp - 2018/08/10
- 2. Các vấn đềhiện tại?
- 3. Agenda: - What isGroovy? - How Groovy work? - Why Groovy? - Groovy vs Java - Best practice with Groovy in production
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- 5. What is groovy? Groovyis A feature-rich Java-friendly Dynamic language * For the Java platform => A super version of Java
- 6. What is adynamic language? A language that allows the types of variables to be changed at runtime... ...among other things! Difference between dynamic vs static language?
- 7. Groovy History • 2003:Started by James Strachan and Bob McWhirter. • 2004: Commissioned into JSR 241 but was almost abandoned. • 2005: Brought back to life by Guillaume Laforge and Jeremy • Rayner. • 2007: Groovy 1.0. • 2012: Groovy 2.0. • 2014: Groovy 2.3 (official support for JDK 8) • Now : Groovy 2.5 (Stable version)
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- 9. How Groovy work? -Groovy runs in the JVM. - GDK extend JDK => Groovy is syntactically aligned with Java. - Compile to Bytecode like Java
- 10. Groovy Pos (vs.Java) • Easy to learn • Productivity (More concise and meaningful code - Funny typing) • Can call on Java classes. (Coding link Java) • Faster in develop, testing • Addtional operators • Mix Functional with Object Orient Programming (Closure)
- 11. Groovy Cons (vs.Java) • Nhiều lỗi tiềm ẩn với dynamic coding: sai kiểu dữ liệu,.... • IDE không nhắc handle exception • Slower than Java
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- 13. Groovy Features • Closures •Collection literals • Properties (GroovyBeans or POGO) • Multi-line strings • String interpolation • Default arguments • Everything’s an Object (even numbers) • Operator overloading • GPath expressions • Additional operators • And much much more...
- 14. Closures are anonymousfunctions that: o may accept parameters or return a value, o can be assigned to variables, o can be passed as arguments, Demo Groovy Closure
- 15. A both cantake params, return value & do something, but... Lambda expressions: Language facility for implementing functional interfaces • Interfaces with a single abstract method. • Function, Predicate, Supplier, Consumer. Groovy closures: • Can be assign as variable • Can be reference to default param by "it" • Use like Functional Programming Groovy Closure <> Java 8 Lambda
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- 17. "def" keyword Người đọckhông hiểu dữ liệu trả về. (Đặc biệt với đoạn dài) => Gây khó khi đọc hiểu & maintain
- 18. Don't use "if"with Object Groovy truth and equals • Null value is false. • Empty collection or map is false. • Empty string is false. • Zero value is false. Best pratices: - Chỉ nên sử dụng với Boolean - Các trường hợp dùng với Type Number rất dễ nhầm - Các trường hợp check List/String nên check cả null (StringUtils.notBlank()/CollectionUtils.notEmpty())
- 19. Don't use "if"with Object
- 20. • GString. (Doublequote: "This is GString: ${1 + 1}") Can be calculate, evaluate method.... • String. • Single quote: 'This is String' • Double quote: "This is String" - Like Java String => Don't use GString when unnecessary (String constant) String vs GString
- 21. Use multiple line Stringvs GString
- 22. "?:" operator => Hữudụng khi dùng để set default value Vấn đề: - Các trường hợp String blank hoặc Number value 0 - KQ: 10 & 10
- 23. Null Safe operator WithNull safe Without Null safe
- 24. with() method Check condition Setmultiple value Use like builder
- 25. Collection In Groovy •Find/Filter • Map • List to Map • Grep (exclude null, empty elements)
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- 27. • Use operator: '==' (compare String), '=~' (Check regular/Contains) • Operator: '+', '-' (add, remove with List) • Parse Date: Date.parse(...), Date.format(...) Groovy best practices (Continues)
- 28. • Annotations: • @InheritConstructors •@TupleConstructor • @Slf4j • @CompileStatic • @Singleton Groovy best practices (Continues)
- 29. • Groovy 2Cookbook • Programming Groovy 2 • Blog: http://mrhaki.blogspot.com • Groovy Web Site: http://groovy.codehaus.org How to start with Groovy?