Equality test for numeric value input parameter received as String data type

Question

I am receiving a numeric value input parameter that is a String data type (something that I cannot change) and I need to check that this value received is of a certain number. I.e. Check if the value is 5.

Knowing that the received value of String data type, but at all times it will should contain only numbers. I would first convert the value into an integer data type, and then perform the equality test. I.e. Case B illustrated below.

Case A:

String expected = "3"; 

if(expected.equals(actual)) //...

Case B:

int expected = 3;

int actualInt = Integer.parseInt(actual);

if(expected == actualInt) //...

I would like to find out if there will be any cons in performing the equality test using Case B as I am more inclined to do it that way as a correct way out.

Answer 1

Use Try-Catch:

int expected = 3;
int actualInt;
try
{
    actualInt = Integer.parseInt(actual);

    if(expected == actualInt) //...
}
catch(NumberFormatException ex)
{
    // You will reach here when a bad input is given to the parseInt method
    // Handle the failure
}
catch(Exception e)
{
    // All other exceptions here
}

Even though you know that the string is always going to have a "numeric" value, it is still a good practice to implement exception handling. Better safe than worry :)

Answer 2

If you are only going to do equality check then I think case A is fine, since you are not doing any operations that will require you the number instead of a string.

Only cons I could see with case B, is that you would have to parse the number out of the string for the equality check.

But the advantage of case B is that if you needed to make sure that the string is actually an integer, in which case, you would have to go with case B.