Downloaded 11 times
![Extension methods
class HelloWorld {
def static print(String s){
println(s)
}
def static void main(String[] args){
"Hello World".print()
}
}](https://image.slidesharecdn.com/thebestofaltjavaisxtend-170617091247/75/The-best-of-AltJava-is-Xtend-13-2048.jpg)
![Extension methods
class StringExtensions {
def print(String s){ ... }
}
class HelloWorld {
static extension StringExtensions extensions = …
def static void main(String[] args){
"Hello World".print()
}
}
Import extension methods
defined in other class](https://image.slidesharecdn.com/thebestofaltjavaisxtend-170617091247/75/The-best-of-AltJava-is-Xtend-14-2048.jpg)
![Lambda expressions
def static void main(String[] args){
val list = Arrays.asList("Kotlin", "Java", "Xtend")
Collections.sort(list) [ a, b |
a.length - b.length
]
println(list)
}
Translated to lambda](https://image.slidesharecdn.com/thebestofaltjavaisxtend-170617091247/75/The-best-of-AltJava-is-Xtend-15-2048.jpg)
![Dispatch methods
def static dispatch printType(Number x) {
"it's a number"
}
def static dispatch printType(Integer x) {
"it's an int"
}
def static void main(String[] args){
println(10.printType)
}](https://image.slidesharecdn.com/thebestofaltjavaisxtend-170617091247/75/The-best-of-AltJava-is-Xtend-16-2048.jpg)
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Similar to The best of AltJava is Xtend
The best of AltJava is Xtend
- 1. The best ofAltJava is Naoki Takezoe @takezoen BizReach, Inc #渋谷java
- 2. What's Xtend? ● Hostedby Eclipse Foundation ● Based on Xtext ● Similar syntax to Scala or Kotlin ● Compiled to Java source code (not class file) ● Eclipse and IntelliJ support
- 3.
- 4.
- 5.
- 6.
- 7. Tool support ● IDEPlugins ○ Eclipse ○ IntelliJ IDEA (not work with IntelliJ 2017.1.2?) ● Build tools ○ Maven ○ Gradle
- 8. Eclipse support You caninstall Xtend support from the update site.
- 9. About Xtext ● Frameworkfor development of languages ● Define language using BNF like DSL ● Generate toolkit like parser or editor from it Language Definition Parser Compiler Linker Type checker Editor Generate
- 10. Xtext Summit ● InEclipseCon 2017 France ● June 20-21 (2days!!) ● One of the hottest projects in Eclipse.org
- 11.
- 12. Basic syntax ● def/ var / val ● () in method invocation is optional ● return and return type are optional ● null-safe call: myRef?.doStuff ● All exceptions are treated as runtime ● if, try, switch and block are expression (for and while are void, unfortunately)
- 13. Extension methods class HelloWorld{ def static print(String s){ println(s) } def static void main(String[] args){ "Hello World".print() } }
- 14. Extension methods class StringExtensions{ def print(String s){ ... } } class HelloWorld { static extension StringExtensions extensions = … def static void main(String[] args){ "Hello World".print() } } Import extension methods defined in other class
- 15. Lambda expressions def staticvoid main(String[] args){ val list = Arrays.asList("Kotlin", "Java", "Xtend") Collections.sort(list) [ a, b | a.length - b.length ] println(list) } Translated to lambda
- 16. Dispatch methods def staticdispatch printType(Number x) { "it's a number" } def static dispatch printType(Integer x) { "it's an int" } def static void main(String[] args){ println(10.printType) }
- 17. Switch expressions def length(Objectx) { switch x { String case x.length > 0 : x.length List<?> : x.size default : -1 } } Type guard and case guard are available
- 18. Template expressions def someHTML(Stringcontent) ''' <html> <body> «content» </body> </html> ''' Three single quote! Embed variables as «...»
- 19. Active annotations (Macro) @Dataclass User { long userId String userName String email } Generate code triggered by annotation
- 20.
- 21. Xtend... ● has simpleand powerful syntax. ● has excellent Eclipse support. ● covers Web, GUI and Android. ● offers 100% Java interop.
- 22.