[ GroovyGN ] The Spread-Dot Operator

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Preface: 
Groovy adds some nice operators to the language to write brief code. We already learned about the Elvis operator and the Spaceship operator. And now we see what the spread-dot operator is about and what it does. The spread-dot operator (*.) is used to invoke a method on all members of a Collection object. The result of using the spread-dot operator is another Collection object. 

Sample Code: 

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1. class Language {  
2.     String lang  
3.     def speak() { "$lang speaks." }  
4. }  
5.   
6. // Create a list with 3 objects. Each object has a lang   
7. // property and a speak() method.   
8. def list = [       
9.     new Language(lang: 'Groovy'),       
10.     new Language(lang: 'Java'),       
11.     new Language(lang: 'Scala')   
12. ]    
13.   
14. // Use the spread-dot operator to invoke the speak() method.   
15. assert ['Groovy speaks.', 'Java speaks.', 'Scala speaks.'] == list*.speak()   
16. assert ['Groovy speaks.', 'Java speaks.', 'Scala speaks.'] == list.collect{ it.speak() }    
17.   
18. // We can also use the spread-dot operator to access   
19. // properties, but we don't need to, because Groovy allows   
20. // direct property access on list members.   
21. assert ['Groovy', 'Java', 'Scala'] == list*.lang   
22. assert ['Groovy', 'Java', 'Scala'] == list.lang  

Supplement: 
* Groovy User Guide - Operators 
* Dynamic object orientation - Using power features