Precedencia de Operadores

The precedence hierarchy of the operators, some of which we haven't looked at yet, is, from highest to lowest:

1. $(scope escape)
2. new ()(parentheses)
3. [](subscripting) ()(method call) {}(closable block) [](list/map)
4. . ?. *. (dots)
5. ~ ! $ ()(cast type)
6. **(power)
7. ++(pre/post) --(pre/post) +(unary) -(unary)
8. * / %
9. +(binary) -(binary)
10. << >> >>> .. ..<
11. < <= > >= instanceof in as
12. == != <=>
13. &
14. ^
15. |
16. &&
17. ||
18. ?:
19. = **= *= /= %= += -= <<= >>= >>>= &= ^= |=

Aún no hemos estudiado todos los operadores, como es el caso de *.. Veamos un ejemplo de uso:

generaciondecodigos@nereida:~/Lgroovy/collections$ cat -n spreadDotOperator.groovy 
     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  println list*.speak() 
    16  println 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  println list*.lang 
    22  println list.lang

Al ejecutarse, este programa produce la siguiente salida:

generaciondecodigos@nereida:~/Lgroovy/collections$ groovy spreadDotOperator.groovy 
[Groovy speaks., Java speaks., Scala speaks.]
[Groovy speaks., Java speaks., Scala speaks.]
[Groovy, Java, Scala]
[Groovy, Java, Scala]