Changing java source code

Question

I am writing a program that will change java code. It changes the next-line bracket system into the end-of-line bracket system. I am using String to do this. Here is my code:

public static void main(String[] args) throws Exception
{   
    File file = new File("test.text");
    //PrintWriter output = new PrintWriter(file);
    Scanner input = new Scanner(file);

    System.out.println("Does it exist? " + file.exists());
    while(input.hasNext())
    {
        String first = input.next();
        String second = input.next();

        if (first == "{")
        {
        second = first.replace("{", "\n{");
        System.out.println(second);
        }
        else
        {
        System.out.println(first);
        }
    }
}

My test.txt looks like:

"hello{  how are you{"

So far it just takes out the word before the bracket. I am trying to get it to put the bracket on a new line.

Is this as an academic exercise? In any case, you compare strings with String.equals(), not ==. And you don't want to check for "{" anyway, you want to check for a "{" with nothing before it except whitespace. If it's not just for fun, use Jalopy/etc. — Dave Newton
– Dave Newton, Commented Jan 17, 2012 at 20:53
As a first step, I would focus on detecting the opening braces. Try to write a program that prints the file exactly as it is, except that it would print some marker after each line containing an opening brace. For the purposes of this exercise, please use just one variable instead of first/second (I think at this stage they're confusing more than they're helping). — NPE
– NPE, Commented Jan 17, 2012 at 20:55
This is what I am trying to do. In theory it should be printing "hello" and then the bracket on the next line. — Josh
– Josh, Commented Jan 17, 2012 at 20:58
I have changed the code with contains and it worked. I then optimized it with Luchian's answer. Now should I just print all the code to the file and then do the while loop? — Josh
– Josh, Commented Jan 17, 2012 at 21:04
Why don't you just try it (after saving a back-up) and see if it works. If it doesn't come back with a new question and a specific problem. We can't test the code for you. (Well, we can... but so can you). — Luchian Grigore
– Luchian Grigore, Commented Jan 17, 2012 at 21:15

Luchian Grigore · Accepted Answer · 2012-01-17 20:55:37Z

1

You need to compare strings using .equals().

But you don't need comparison, you need to see if the first string contains {, so you should be using contains.

EDIT: Come to think of it, there's no need for contains either, or for two variables. One should do it:

while(input.hasNext())
{
    String first = input.next();
    String second = first.replace("{", "\n{");
    System.out.println(second);
}

answered Jan 17, 2012 at 20:55

Luchian Grigore

260k68 gold badges465 silver badges634 bronze badges

Sign up to request clarification or add additional context in comments.

Comments

kosa · Accepted Answer · 2012-01-17 20:54:12Z

0

first .equals( "{"); when you compare strings you need to use equals not ==

answered Jan 17, 2012 at 20:54

kosa

66.7k15 gold badges134 silver badges170 bronze badges

Collectives™ on Stack Overflow

Changing java source code

2 Answers 2

Comments

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

Comments

Comments

Your Answer

Sign up or log in

Post as a guest

Related