Question

i have recrusive function which works fine. The problem is it gives stackoverflow error when the number of lines are huge. I want to put it in iterative, probably using a for loop. Need some help in doing it.

private TreeSet validate(int curLine, TreeSet errorSet) {
    int increment = 0;
    int nextLine = 0;

    if (curLine == lines.length || errorSet.size() != 0) {
        return errorSet;
    } else {
        String line = lines[curLine];

        //validation starts.  After validation, line is incremented as per the requirements

        increment = 1 //As per requirement. Depends on validation results of the line

        if (increment > 0) {
            try{
                Thread.currentThread().sleep(100);  
            }catch(Exception ex){
                System.out.println(ex); 
            }
            nextLine = (curLine + increment);
            validate(nextLine, errorSet);
        }
    }

    return errorSet;
} 

Poster’s description of the method:

The method does validates textlines, these lines has instructions of how much line has to be skipped, if the line is valid. So, if the line is valid that many of lines will be skipped using the increment. if the line is not valid increment will be 0.

Answer 1

I’m not sure why this was ever recursive in the first place. This is perfectly suited for the use of a FOR loop. use something like so:

private TreeSet validate(int curLine, TreeSet errorSet) { 
   int increment = 0;

   if (errorSet.size() != 0)
      return errorSet;

   for (int curLine = 0; curLine < lines.Length; curLine += increment)
   {
      // put your processing logic in here


      // set the proper increment here.
   }
}

If the increment is always going to be 1, then you can just use curr++ instead of curLine += increment