CODEWITHSUNDEEP
javaexceptionthrow
14k.wizard
14k.wizard

Reputation: 41

display exception in JTextField

My code does some arithmetic to convert a binary input to decimal output. I also made an exception class that extends NumberFormatException to throw an error if the input is not a 1 or 0. What I want is to throw the exception to a JTextField.

    private void biTodeciActionPerformed(java.awt.event.ActionEvent evt) {                                         
    // TODO add your handling code here:
String binary;
binary = binaryStringText.getText();
int total = 0;
for(int i = 0; i < binary.length(); i++)
{
    if (binary.charAt(i) != '0' && binary.charAt(i) != '1')
    {
        throw new ParseMethods.BinaryNumberFormatException(binary.charAt(i)+" is not"
                +" a valid binary input.");
    }
    else if(binary.charAt(i) == '1'){
        total += Math.pow(2, (binary.length()-1)-i );
    }
}

deciOut.setText(""+total);
}

Upvotes: 1

Views: 438

Answers (2)

D Johnson
D Johnson

Reputation: 36

Print exception directly into textfield in STRING format deciOut.setText(""+exp);

Upvotes: 0

MadProgrammer
MadProgrammer

Reputation: 347314

Essentially, what you're trying to do won't work. The BinaryNumberFormatException doesn't declare that it throws any exceptions (and assuming you're using NetBeans), you won't be able to (easily) modify it.

You could wrap all you code in a try-catch block within the method, but that's just, well, kind of messy (IMHO)

Instead, what I might do, is create a class which does the conversation, something like...

public static class BinaryConverter {
    public static String toDecimal(String binary) throws BinaryNumberFormatException {
        //...
    }

    // Maybe a toBinary method as well...
}

for example. The toDecimal declares the fact that it will throw a BinaryNumberFormatException (although I think some kind of parse exception would be better)

Then in your action performed method, you could do something like...

private void biTodeciActionPerformed(java.awt.event.ActionEvent evt) { 
    try {
        deciOut.setText(BinaryConverter.toDecimal(binaryStringText.getText()));
    } catch (BinaryNumberFormatException exp) {
        exp.printStackTrace();
        deciOut.setText(exp.getMessage());
    }
}

which would allow to deal with the operation been successful and unsuccessful in a more succinct manner.

This makes the code more reusable and easier to manager.

As an idea

Upvotes: 2

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