"$action"(param1, param2) isn't working but method(param1, param2) does

So I am trying to avoid having a switch or bunch of if statements where I have a json request coming in and it has a property called action. That action is also the name of my closure method. But when I try using

"$jsonData.action"(params) I get an error

groovy.lang.MissingMethodException: No signature of method: GroovyScript.gameTableList() is applicable for argument types: (java.util.HashMap) values: [[action:gameTableList]]

but if I call the method with

gameTableList(params) it works.

Is there another way to dynamically call methods?

Thanks

Mark

The issue is that the methods/closures were defined as

def function = { params ->
}

By changing it to

def function(params) {
}

The code now works.

Mark