package test.io;
 
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.BufferedWriter;
import java.io.PrintWriter;
import java.io.FileWriter;
 
import java.io.IOException;
 
import org.apache.log4j.Category;
import org.apache.log4j.BasicConfigurator;
/**
  * @author <a href="tsmets@lautre.net">Thomas SMETS</a>, Brussels
  */
public class ReadingLineAndProcessing
{
  public static Category log = Category.getInstance (ReadingLineAndProcessing.class);
  public static final String USAGE 
    = "java test.io.ReadingLineAndProcessing <aFileNameToProcess>";  
  public static final String PROPERTY_LINE_SEPARATOR = "line.separator";
  public static final String LINE_SEPARATOR = System.getProperty (PROPERTY_LINE_SEPARATOR);
  public static final String TEMP = "Temp_";
  
 
  public static void main (String[] args)  
  {
    BasicConfigurator.resetConfiguration ();
    BasicConfigurator.configure ();
    
    if (args.length < 1)
      printUsage ();
    
    BufferedReader in = new BufferedReader(new FileReader( args[0] ));
    PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(TEMP + args[0])));
    
    String S, pS;
    while ((S = in.readLine ()) != null )
    {
      log.info ("Reading a line : " + S);
      pS = processString (S);
      out.write (pS);
      out.write (LINE_SEPARATOR);
    }  
    
    out.flush ();
    out.close ();
    in.close ();
    
    log.info ("Re-copying");
    
    in = new BufferedReader(new FileReader(TEMP + args[0] ));
    out = new PrintWriter(new BufferedWriter(new FileWriter(args[0])));
    
    while ((S = in.readLine ()) != null )
    {     
      out.write (S);
      out.write (LINE_SEPARATOR);
    }
        
    out.flush ();
    out.close ();
    in.close ();
    
    log.info ("Copied ...");
  }
  
  public static String processString (String s)
  {
    String processedS;        
    return processedS = s + s;
  }
  
  public static void printUsage ()
  {
    System.out.println (USAGE);
  }
}