![@NamedParams
● Mainly to give IDE hints for mapped parameters
● @NamedParams([array of @NamedParam])
● Can optionally tell what type is expected
Task task(@NamedParams([
@NamedParam(value = "name", type = String.class),
@NamedParam(value = "type", type = Class.class),
@NamedParam(value = "doLast", type = Closure.class),
@NamedParam(value = "doFirst", type = Closure.class),
@NamedParam(value = "depends", type = List.class)
]) Map<String, Object> map)](https://image.slidesharecdn.com/groovydsls-190526135509/85/Writing-Groovy-DSLs-4-320.jpg)
![Groovy 3.0
●
Lambda expressions and :: supported
●
New operators:
– !in
– !instanceof
– ?=
– ?[x]](https://image.slidesharecdn.com/groovydsls-190526135509/85/Writing-Groovy-DSLs-13-320.jpg)
![Groovy DSLs: JSONBuilder
def json = new groovy.json.JsonBuilder()
def root = json { // call(Closure)
person { // methodMissing( “person”, [Closure] )
firstName 'Adam' //methodMissing( “firstName”, [Adam] )
lastName 'Davis'
address( //methodMissing( “address”, [Map] )
city: 'Orlando',
country: 'USA',
zip: 32765
)
married true
// a list of values
conferences 'JavaOne', 'Gr8conf'
}
}](https://image.slidesharecdn.com/groovydsls-190526135509/85/Writing-Groovy-DSLs-14-320.jpg)
![Groovy DSLs: Gradle
//def task(object)
task myTask //propertyMissing(“myTask”)
task myTask { configure closure }
//methodMissing(“myTask”, [closure])
task myTask(type: SomeType)
//methodMissing(“myTask”, [map])
task myTask(type: SomeType) { configure closure }
//methodMissing(“myTask”, [map,closure])](https://image.slidesharecdn.com/groovydsls-190526135509/85/Writing-Groovy-DSLs-15-320.jpg)
Writing Groovy DSLs
- 1. Adam L. Davis The Solution Design Group, Inc. @adamldavis.com thesdg.com Writing Groovy DSLs
- 2. Agenda ● Command Chains and @NamedParams ● Operator Overloading ● Categories, Extension modules ● Closures, with, delegate, owner ● propertyMissing, methodMissing ● Groovy Scripts, GroovyShell ● Groovy 3.0 ● Common DSLs
- 3. Command Chains ● Command Chains allows parenthesis-free fluent method calls ● EX: method(param).then(foo) can be written method param then foo
- 4. @NamedParams ● Mainly to give IDE hints for mapped parameters ● @NamedParams([array of @NamedParam]) ● Can optionally tell what type is expected Task task(@NamedParams([ @NamedParam(value = "name", type = String.class), @NamedParam(value = "type", type = Class.class), @NamedParam(value = "doLast", type = Closure.class), @NamedParam(value = "doFirst", type = Closure.class), @NamedParam(value = "depends", type = List.class) ]) Map<String, Object> map)
- 6. Demo 0
- 7. Categories, Extension modules ● Category – use(YourCategory) { *DSL* } – YourCategory has static methods, first parameter is class to decorate – Unlike using metaclass, allows static compilation ● Extension Modules! – Much like Category but everywhere – Put file in META-INF/groovy/ – “org.codehaus.groovy.runtime.ExtensionModule”
- 8. Closures, with, delegate, owner ● Closures { } ● object.with { * all methods, properties of object available here * } ● Closure.delegate = myThing ● Closure.owner = myThing ● method(@DelegatesTo(Foo) Closure param) – Tells the compiler/IDE the class of the delegate – Allows for auto-completion (in IntelliJ IDEA)
- 9. Demo 1
- 10. propertyMissing, methodMissing ● def propertyMissing(String name): called whenever something could be a property reference. – with/delegate/script-base: allows on the fly reference of anything. – propertyMissing(String name, value): assignment. ● def methodMissing(String name, args): – Name = name of method – Args = array of arguments to method (0..n)
- 11. Groovy Scripts ● No class or main(args) needed ● GroovyShell ● Ability to customize – ImportCustomizer – CompilerConfiguration – Binding – Change the script base-class – Supply a class-loader
- 12. Demo 2
- 13. Groovy 3.0 ● Lambda expressions and :: supported ● New operators: – !in – !instanceof – ?= – ?[x]
- 14. Groovy DSLs: JSONBuilder def json = new groovy.json.JsonBuilder() def root = json { // call(Closure) person { // methodMissing( “person”, [Closure] ) firstName 'Adam' //methodMissing( “firstName”, [Adam] ) lastName 'Davis' address( //methodMissing( “address”, [Map] ) city: 'Orlando', country: 'USA', zip: 32765 ) married true // a list of values conferences 'JavaOne', 'Gr8conf' } }
- 15. Groovy DSLs: Gradle //def task(object) task myTask //propertyMissing(“myTask”) task myTask { configure closure } //methodMissing(“myTask”, [closure]) task myTask(type: SomeType) //methodMissing(“myTask”, [map]) task myTask(type: SomeType) { configure closure } //methodMissing(“myTask”, [map,closure])
- 16. Groovy DSLs: GrooCSS ‘.myclass’.$ {} // Extension module: String width 10.em // Extension module: Number { width 400.px height 200.px color black } //Command chains keyframes ‘flash’ { 10 % { color white } 50 % { color black } 100% { color white } } // operator overloading
- 17. Thanks! Any ?’s Adam L. Davis The Solution Design Group, Inc. @adamldavis.com github.com/adamldavis/2019-gr8conf or http://bit.ly/Gr8-2019BG thesdg.com
- 18. This work is licensed under a Creative Commons Attribution-ShareAlike 3.0 Unported License. It makes use of the works of Mateus Machado Luna. Thanks!