Question

I have the following text file (not a java file)

/*START OF CHANGES TO CODE*/
public class method1 {

    public static int addTwoNumbers(int one, int two){
        return one+two;
    }

    public static void main (String[] args){
        int total = addTwoNumbers(1, 3);
        System.out.println(total);
    }
}
/*END OF CHANGES TO CODE*/

I am trying to use the following code to read the file

String editedSection = null;
boolean containSection = false;
Scanner in = new Scanner(new FileReader(directoryToAddFile));
while(in.hasNextLine()) {
    if(in.nextLine().contains("/*START OF CHANGES TO CODE*/")) {
        containSection = true;
        editedSection = in.nextLine().toString();
    } else if (containSection == true) {
        editedSection = editedSection+in.nextLine().toString();
    } else if (in.nextLine().contains("/*END OF CHANGES TO CODE*/")) {
        containSection = false;
        editedSection = in.nextLine().toString();
    }
    in.nextLine();
}

So basically what i want it to do is read a file till it see’s /*START OF CHANGES TO CODE*/, then start adding every line after this to a string till it reaches /*END OD CHANGES TO CODE*/. But when it is reading lines it ignores some lines and parts of others. Does anyone know how to do this?

Answer 1

You’re calling in.nextLine() lots of times within that while loop. That sounds like a really bad idea to me. How many times it will execute on each iteration will depend on which bits it went into… nasty.

I suggest you use

while(in.hasNextLine()) {
    String line = in.nextLine();
    // Now use line for the whole of the loop body
}

That way you won’t accidentally skip lines by reading them just for checking purposes.