Groovy convert from List to var args for method call

Question

I am using a plugin that provides email functionality as follows:

class SendSesMail {      //to     void to(String ... _to) {          this.to?.addAll(_to)         log.debug "Setting 'to' addresses to ${this.to}"     }  } 

The documentation states the class is called as follows:

sesMail {     from "[email protected]"     replyTo "[email protected]"     to "[email protected]", "[email protected]", "[email protected]"     subject "Subject"     html "Body HTML" } 

In the code a List of addresses is built up and I'm trying to figure out how to convert this list to the var args expected by the method.

Converting to a String concatenated with "," doesn't work as this is an invalid email address. I need to be able to separate each List item into a separate parameter to avoid having to iterate over the List and send each email individually.

Answer 1

Probably the spread operator, *, is what you're looking for:

def to(String... emails) {     emails.each { println "Sending email to: $it"} }  def emails = ["[email protected]", "[email protected]", "[email protected]"] to(*emails) // Output:  // Sending email to: [email protected] // Sending email to: [email protected] // Sending email to: [email protected] 

Notice that the parentheses on the method call to to are mandatory, as otherwise to *emails would be parsed as a multiplication. Bad choice of overloaded grammar symbols IMO =P