CODEWITHSUNDEEP
groovyjenkins-groovy
overexchange
overexchange

Reputation: 1

How to pass methods in Jenkins Groovy?

Below is the Jenkins groovy code in scripted pipeline, we use to pass methods

def dict = [:]
def register(String x, Closure y){ dict[x]=y }

we say register('a', this.&foo) to pass a method to register() accepting closures as second argument

where foo() is a method

def foo(parm){
   // do something with parm
}

where parm's possible value is 'a'

What should be the type of second argument of register method to avoid passing this.&foo and rather invoke register('a', foo)?

Upvotes: 0

Views: 3123

Answers (2)

Dorcioman
Dorcioman

Reputation: 636

Function reference can be obtained using the "&" character; e.q this.&bar

def foo(Closure c) {
   c("foo")
 }

def bar(arg) {
    println "Hellow World: ${arg}"
 }
 
 println(foo(this.&bar))

 Output:
     Hellow World: foo

Upvotes: 0

Szymon Stepniak
Szymon Stepniak

Reputation: 42272

If you want to invoke register('a', foo) then foo has to be a closure like e.g.

def foo = {
    // closure body here
}

instead of 

def foo() {
    // method body here
}

The construction this.&foo is called method pointer operator and it is used to transform a method to a closure. If foo has to remain a method then you can't avoid this.&foo operator. Groovy does not support passing methods as foo. On the other hand, your register method expects a closure as a second parameter, so have to options:

  • define foo as a closure
  • or transform foo method to a closure with this.&foo operator

Upvotes: 2

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