Groovy : spread-dot operator (*.)

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.

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
​