Is there another method to replace Exception message with custom message instead of try{}catch(Exception e){} method?

Question

Instead of the try{}catch(Exception e){} method, is there a way to just state a custom message that replaces the exception message when exceptions like InputMismatchException, NoSuchElementException etc. occurs anywhere on the program?

EDIT: I want another method because if I use try{}catch(Exception e){} method than I will have to do it everywhere and the code also becomes longer.

For example:

public static String genderOutput()
    {

        try
        {

            System.out.print("\nMale   - 1 \nFemale - 2 \n\nEnter either 1 or 2: ");

            int genderInput = userInput.nextInt();

            if(genderInput == 1)
            {

                String userGender = "Mr.";

                return userGender;

            }

            else if(genderInput == 2)
            {

                String userGender = "Mrs.";

                return userGender;

            }

            else
            {

                String userGender = " ";

                return userGender;

            }

        }

        catch (Exception e)
        {

            return null;

        }

    }

I have this function, now if there were multiple functions in a class like this then I would have to have the try{}catch(Exception e){} method everywhere. Wouldn't it be more efficient if you can just replace the exception message with your own and when such exception occurs which has a custom message stated to them then it would just throw out the custom message instead. This way, the code will be shorter as well.

SOLUTION TO MY PROBLEM:

public class Test
{

    public static Scanner userInput = new Scanner(System.in);

    public static String titleName = "TheRivalsRage";
    public static String exitLevelMessage = "Program exited!";
    public static String errorMessageTitle = "\n[Error] ";

    public static String intInputMismatchException = "Please enter an Integer Value!";
    public static String intNoSuchElementException = "Please enter either '1' or '2' without the quotes!";
    public static String lineNoSuchElementException = "Please enter something!";
    public static String bothIllegalStateException  = "Scanner closed unexpectedly!";

    public static void main(String[] args)
            throws Exception
    {

        String usernameOutput;
        String userGender;

        try
        {

            System.out.print("Enter your username: ");

            usernameOutput = userInput.nextLine();

            userGender = genderOutput();

            userInput.close();

        }

        catch(IllegalStateException e)
        {

            throw new IllegalStateException(errorMessageTitle + bothIllegalStateException);

        }

        if(userGender == null)
        {

            noSuchElementException();

        }

        else
        {

            System.out.println("\nWelcome " + userGender + " " + usernameOutput + " to " + titleName);

        }

    }

    public static String genderOutput()
    {

        String userGender;

        int genderInput;

        System.out.print("\nMale   - 1 \nFemale - 2 \n\nEnter either 1 or 2: ");

        try
        {

            genderInput = userInput.nextInt();

        }

        catch(InputMismatchException e)
        {

            genderInput = 0;

            inputMismatchException();

        }

        if(genderInput == 1)
        {

            userGender = "Mr.";

        }

        else if(genderInput == 2)
        {

            userGender = "Mrs.";

        }

        else
        {

            userGender = null;

        }

        return userGender;

    }

    public static void inputMismatchException()
            throws InputMismatchException
    {

        throw new InputMismatchException(errorMessageTitle + intInputMismatchException);

    }

    public static void noSuchElementException()
            throws NoSuchElementException
    {

        throw new NoSuchElementException(errorMessageTitle + intNoSuchElementException);

    }

}

The only thing you can do (if it's *your own* that is throwing the exception) is to throw it like this: `throw new InputMismatchException("Message");` — Cardinal System, Aug 05 '17 at 15:41
Please read the Edited Line. I just want to know if there is a much more efficient way to do it. Don't just down-vote it. — RedAISkye, Aug 05 '17 at 15:48
Are you talking writing your own Exception class?? I think this link will help you: https://stackoverflow.com/a/1754473/8412149 — MERT TOSLALI, Aug 05 '17 at 15:53
Kind of like that, just wanted to replace certain types of exceptions with a custom message. — RedAISkye, Aug 05 '17 at 16:27

score 1 · Accepted Answer · answered Aug 05 '17 at 17:50

don't handle exception in each and every method just use throws Exception after method signature and handle it at end where the methods are being called. and there in catch block you can throw your custom exception.

 void method1() throws Exception{
//
}

void method2() throws Exception{
//
}

   void finalmethod(){
        try{
          method1();

          method2();

        }catch(InputMismatchException e){
                  throw customExcpetion("custommessage1");
        }catch(Exception e){
            throw customExcpetion("custommessage2");
        }
    }

Ah! Thanks so much for the help! I find this one to be much easier and efficient so far. — RedAISkye, Aug 05 '17 at 20:39

score 0 · Answer 2 · answered Aug 05 '17 at 15:42

0

You need a try/catch.

However, you do not need to catch all exceptions separately, because the exceptions that you mention are all subclasses of RuntimeException. Hence, it is sufficient to make a single try/catch in your main to intercept RuntimeException, and print the replacement message:

public static void main(String[] args) {
    try {
        ... // Actual code
    } catch (RuntimeException ex) {
        System.err.println("A runtime error has occurred.");
    }
}

answered Aug 05 '17 at 15:42

Sergey Kalinichenko

714,442
84
1,110
1,523

This is a better way of doing it but will it work on functions when they are called as well? – RedAISkye Aug 05 '17 at 15:50
But for example: InputMismatchException and NoSuchElementException are different errors so they'll have their own message and not a single message. – RedAISkye Aug 06 '17 at 15:02

score 0 · Answer 3 · answered Aug 05 '17 at 15:51

0

You can try Aspectj or Spring aop by creating around advice. You can replace message by catching exception inside advice and rethrow.

Check http://howtodoinjava.com/spring/spring-aop/aspectj-around-advice-example/ To know about how to use spring aop for anound advice

answered Aug 05 '17 at 15:51

Noman Khan

920
5
12

I'm a beginner so that will be too much for me right now. I just want some kind of method on the Java itself. – RedAISkye Aug 05 '17 at 15:55

davidxxx · Answer 4 · 2017-08-05T16:06:53.007

Java doesn't provide this feature out of the box but nobody prevents you to create a class that composes a Scanner object and that decorates methods that you are using as nextInt().

Inside the decorated method, invoke nextInt(), catch the exception that it may throw and handle it by returning null as in your question.
If it makes sense, you could even provide a nextInt() method with a default value as parameter if the input fails.

public class MyCustomScanner{

   private Scanner scanner;
   ...
   public Integer nextInt(){
       try{       
            return scanner.nextInt()
       }
       catch(InputMismatchException e){
           myStateObj.setErrorMessage("....");
           return null;
       }
   }
   public Integer nextInt(Integer defaultValue){
       try{       
            return scanner.nextInt()
       }
       catch(InputMismatchException e){
           myStateObj.setErrorMessage("....");
           return defaultValue;
       }
   }
}

Now you can use the class in this way :

MyCustomScanner scanner = new MyCustomScanner();
Integer intValue = scanner.nextInt();
Integer otherIntValue = scanner.nextInt(Integer.valueOf(4));

Is there another method to replace Exception message with custom message instead of try{}catch(Exception e){} method?

4 Answers4