Reading in a file

[Victoria Preston]

I have to read in a file that will be be given at run time but everytime i run the program it hangs. I mean it runs and runs and runs but is doing nothing. Here is the code.

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Scanner;
 
public class ClassBuilder
{

public ClassBuilder()
{
toString();
}

public static String getInteractiveInfo()
{
Scanner in = new Scanner(System.in);


System.out.println("Welcome to Class Builder");

System.out.print("Enter class name:");
String a = in.next();


System.out.print("Enter field name(* to stop)");
String b = in.next();

System.out.print("Enter field type:");
String c = in.next();

System.out.print("Enter R (readable), W (writeable), or RW (both):");
String d = in.next();

System.out.print("Enter default value:");
String e = in.next();

ClassDef cd1 = new ClassDef(a);
cd1.addField(new FieldDef(c,b,e,d));

String result = cd1.toString();

return result ;
}
     
public static void main(String[] args)
{
ClassBuilder c = new ClassBuilder();
ClassDef cd2 = new ClassDef();
if(args[0].equalsIgnoreCase("-i"))
{
String result = getInteractiveInfo();
//write result to System.out
System.out.println(result);
}
else
{
String defFile = args[0];
String javaFile = args[1];

BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
String className = null;
 try { 
         className = br.readLine(); 
      } catch (IOException ioe) { 
         System.out.println("IO error trying to read class name!"); 
         //System.exit(1); 
            String fileName = null;
            try { 
         fileName = br.readLine(); 
      } catch (IOException ie) { 
         System.out.println("IO error trying to read file name!");
         
         String result1 = cd2.toString();
         System.out.println(result1);
         System.exit(1); 
      }

System.out.println("test");



//batchmode();
}
  }      
}    

[Ernest Friedman-Hill]

As written, if the first argument is "-i", then you'll be prompted for input; but if it's not, then the program will read a line from the console without prompting. Is that what you intend? Is it "hanging" just because it's waiting for that one line?

There can actually be some issues with data gettting "stuck" when you use BufferedReader with System.in. You always need to turn buffering off by using a 1-character buffer (I added text in bold):

BufferedReader br = new BufferedReader(new InputStreamReader(System.in), 1);

[Victoria Preston]

What it is suppose to do is read input from a file. Not of the screen in -i is not there. I just can't get it to read it.

[Ernest Friedman-Hill]

But you don't open a file anywhere, do you? That would probably mean using a FileReader, and there's none to be found anywhere here.