Question

All variables seem to be global in my groovy scripts I run on groovy script engine. I made some groovy class but when I make variables, they can be accessed from everywhere. for exaple.

class test{
  void func1{ a=4 }
  void func2{ print(a) }
}

When I invoke this class function func1 from scala then invoke func2, it results “4”. Weird thing is if I declare variables like “def a=0” in the function, the scope of the variable will be limited with in the function.

I’m loading my groovy scripts from GroovyScriptEngine like this(using scala)

var gse = new GroovyScriptEngine(pathList.toArray)  
var scriptClass = gse.loadScriptByName(file.getName())
var i = scriptClass.newInstance().asInstanceOf[GroovyObject] 

then using invokeMethod to invoke functions in the groove script class. Is there anyway to make variable scopes limited with in functions by default?

Answer 1

That’s the expected behaviour, described in Scoping and the Semantics of “def”.

Using an undeclared variable in a Groovy script creates a binding variable. Binding variables are global to your script. If you declare your variable with def, it become function local.

This behavior only applies because you load your code as a script. I don’t believe its possible to change it. Just use a declaration (def or a type) when you need a local variable.

Note that you can also define a binding variable (global) by using the @Field annotation:

class test {
  void func1{ @Field int a=4 }
  void func2{ print(a) }
}

is equivalent to

class test {
  void func1{ a=4 }
  void func2{ print(a) }
}