check if Integer is Null or numeric in groovy?

Question

I have a service method and have to throw an error if method parameter is null/blank or not numeric.

Caller is sending an Integer value but in called method how to check if it is numeric or null.

ex:

def add(value1,value2){
 //have to check value1 is null/blank
 //check value1 is numeric

}

caller: class.add(10,20)

Any suggestions around would be appreciated.

Answer 1

More concrete that the answer of Dan Cruz, you can use String.isInteger() method:

def isValidInteger(value) {
    value.toString().isInteger()
}

assert !isValidInteger(null)
assert !isValidInteger('')
assert !isValidInteger(1.7)
assert isValidInteger(10)

But what happens if we pass a String that looks like a Integer for our method:

assert !isValidInteger('10')  // FAILS

I think that the most simple solution is use the instanceof operator, all assert are valid:

def isValidInteger(value) {
    value instanceof Integer
}