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