Getting Error on Non Number

[Steve Dyke]

Try it figure out why I get this error message:

java.lang.NumberFormatException: For input string: ""

On this code:

    editQualityControlPlanItemListDataModelParms.setOverridepercent(Integer.parseInt((request.getParameter("overridepercent") == null || 
    request.getParameter("overridepercent").isEmpty())?"0":request.getParameter("overridepercent").replaceAll(GenericPrams.QMS_ALLOWED_CHARS_NUMBERS, "")));

[Tim Cooke]

What is GenericPrams.QMS_ALLOWED_CHARS_NUMBERS? A regex expression I assume? What is its value?

[Tim Cooke]

And to ask my next question ahead of time.... What are you expecting getParameter("overridepercent") to yield?

[Tim Cooke]

And finally, what Integer value are you expecting to get out of the whole thing?

[Norm Radder]

What is the value returned by this expression:  request.getParameter("overridepercent")
Add a print statement before the posted statements to show its value.  Be sure to add delimiters around the value in the print statement so blanks will show:  

System.out.println(">" + request.getParameter("overridepercent") + "<");

[Steve Dyke]

Tim Cooke wrote:What is GenericPrams.QMS_ALLOWED_CHARS_NUMBERS? A regex expression I assume? What is its value?

public final static String QMS_ALLOWED_CHARS_NUMBERS = "[^0-9]";

[Steve Dyke]

Tim Cooke wrote:And to ask my next question ahead of time.... What are you expecting getParameter("overridepercent") to yield?

Any number or combination of numbers 0-9

[Steve Dyke]

Tim Cooke wrote:And finally, what Integer value are you expecting to get out of the whole thing?

A number representing a percent.

[Steve Dyke]

I think I have posted this in error.
I just realized I made some adjustments to my code base after the error was generated so the line of code the error says it happened in is not what the current line of code is at now.
Sorry.

[Tim Holloway]

In the interest of readability:

    editQualityControlPlanItemListDataModelParms
                    .setOverridepercent(
                          Integer.parseInt((
                             request.getParameter("overridepercent") == null
                   || 
                    request
                       .getParameter("overridepercent")
                           .isEmpty()) ? "0"
                              :request.getParameter("overridepercent")
                                   .replaceAll(GenericPrams.QMS_ALLOWED_CHARS_NUMBERS, ""
                   )));

I'm afraid that the original not only is likely not to fit on smaller displays, but also our formatter tend to obscure critical text.

Note that if you use an IDE's automated pretty-printer, some (depending on settings) may put the "." operators at the end of the line, not the beginning, but I find the operator-at-the-beginning more informative to me.

As for general nit-picking, I'm certainly one for complex statements, but this is a bit much. Also, there are two reasons why breaking this up into simpler statements is a good idea (indentation or not).

First, if you have to step through the code with a debugger, debuggers step per-statement so a LOT of details will be more or less invisible in a complex statement.

Secondly, if you break the code into smaller sequences, it's easier to capture the intermediate values in case you want to print them out to a debug log.

And, if you are REALLY paranoid, you can always put assertions into the code, although I've never seen anyone use the Java assert the way it is in C/C++. Partly, I think because Java's assert is overly complex. Instead we prefer unit-test assertion methods.

Last, but not least, as I've mentioned elsewhere, I prefer to document the allowable data values that go into code. We could, based on context, assume that the percentage can be blank or a number from 0 to 100, but maybe you work for a firm that demands 100%. Or gets negative percentages.

The statement also seems to try to sanitize data. I'm not so kind. If they cram in non-numeric characters into a numeric field, I'm going to reject the whole request. Who knows what else they messed up?

[Liutauras Vilda]

Tim Holloway wrote:The statement also seems to try to sanitize data. I'm not so kind. If they cram in non-numeric characters into a numeric field, I'm going to reject the whole request. Who knows what else they messed up?

Totally.

@OP
i.e. abc1def4. If possible in your use case, you may can to return 400 Bad Request.

Try this version of formatting (note, I extracted some code to variables and inverted some logic, for better readability(?)):

String overrideValue = request.getParameter("overridepercent");
boolean overrideValueProvided = overrideValue != null && !overrideValue.isEmpty();

editQualityControlPlanItemListDataModelParms.setOverridepercent(
        Integer.parseInt(
                overrideValueProvided
                        ? overrideValue.replaceAll(GenericPrams.QMS_ALLOWED_CHARS_NUMBERS, "")
                        : "0"
        )
);