import java.io.File;
import java.util.Arrays;
import java.util.Scanner;
import java.io.IOException;

/** Demo.java - simple experiment with files and directories.
 *  What can we use in java.io.File?
 *  I had originally wanted to call this program File.java, but I can't 
 *  because I include a class called File.  Oh well, I'll just call it Demo.
 *  File's getCanonicalPath() may throw an IOException.
 */
public class Demo
{
  public static void main(String [] args) throws IOException
  {
    // Ask the user for a directory
    Scanner kbd = new Scanner(System.in);
    System.out.printf("Enter name of a directory:  ");
    String name = kbd.nextLine();
   
    File inputFile = new File(name);
    String [] fileList = inputFile.list();
    
    if (fileList == null)
    {
      System.out.printf("Error:  file list is null.  Not a directory.\n");
      System.exit(1);
    }
    Arrays.sort(fileList);
   
    System.out.printf("This directory has %d files.\n", fileList.length);
    long totalLength = 0;
    
    for (int i = 0; i < fileList.length; ++i)
    {
      System.out.printf("For the file %s:\n", fileList[i]);
      
      // Using a File object, look up statistics.
      String pathName = inputFile + "/" + fileList[i];
      File f = new File(pathName);
      
      System.out.println("  canRead() returns          " + f.canRead());
      System.out.println("  canWrite() returns         " + f.canWrite());
      System.out.println("  canExecute() returns       " + f.canExecute());
      System.out.println("  getFreeSpace() returns     " + f.getFreeSpace());
      System.out.println("  getTotalSpace() returns    " + f.getTotalSpace());
      System.out.println("  getUsableSpace() returns   " + f.getUsableSpace());
      System.out.println("  isDirectory() returns      " + f.isDirectory());
      System.out.println("  isFile() returns           " + f.isFile());
      System.out.println("  lastModified() returns     " + f.lastModified());
      System.out.println("  length() returns           " + f.length());
      System.out.println("  getAbolutePath() returns   " + f.getAbsolutePath());
      System.out.println("  getCanonicalPath() returns " + f.getCanonicalPath());
      totalLength += f.length();
    }
    
    System.out.printf("The total size of all files is %d bytes.\n", totalLength);
  }
}