在闭包内调用 Groovy 闭包时出现 MissingMethodException

Question

I have a groovy script which looks similar like below:

def clouser = {
    def clouserOne = { _argsA  -> 
        def clouserTwo = { _argsB ->
            // Do Something with _argsA and _argsB
            println(_argsA)
            println(_argsB)
        }
    }
} 

while calling this

clouser().clouserOne("A").clouserTwo("B")

I am getting an error

groovy.lang.MissingMethodException: No signature of method: Script1.clouserOne() is applicable for argument types: (String) values: [A]
    at Script1.run(Script1.groovy:11)

What is the correct way to define this kind of closure inside closure? And how to call it in a proper way?

Answer 1

The problem with the original code is, that you are defining just some local variables, that never get used. Instead the assigned closure is returned directly.

To make your original code work, you can call:

closure()("A")("B")

(Each closure call returns the next closure and you just chain the calls; of course there is no need to have the def clouserXXX in there).

If you leave the only def out, you will create "global vars" and that is most likely not what you want.

If you want to have the names in there, you have to return something with the names. One simple example is using maps as the return. Eg:

def closure = { ->
    [closureOne: { _argsA  -> 
        [closureTwo: { _argsB ->
            println(_argsA)
            println(_argsB)
        }]
    }]
} 

closure().closureOne("A").closureTwo("B")

Answer 2

After some more reading, I came across more complex closure of closure which will accepts a closure and get executed inside closure. For example:

someClouser = {_args -> _args }

clouser = {
    clouserOne = { String _argOne -> 
        clouserTwo = { String _argTwo, Closure c={any()} -> 
            print "Use _argOne: ${_argOne} and _argTwo : ${_argTwo} and invoke passed clouser ${c.call()} this way" 
        }
    } 
}.call()

and it can be call or use like

clouser.clouserOne("IMAGE").clouserTwo("INSIDE") ​{ 
     someClouser "Hello World" 
}​​​

The result will be

Use _argOne: IMAGE and _argTwo : INSIDE and invoke passed clouser Hello World this way