Java Program to List the Directories,SubDirectories and Files in them

import java.io.File;

import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.util.Comparator;


/**
 * List the Directories, SubDirection and Files in them
 * @author Sudipta Kumar Laha
 *
 */
public class FileStructure {
    /**
     * Print Directories, SubDirection and Files in them
     * @param str
     * 
     */
    public void getFiles(String str){
        System.out.println("[D]\t"+str);
        File f=new File(str);
        File ss[]=f.listFiles();
        

        if(ss!=null){
            Arrays.sort(ss, new sortStructure());
            for(int i=0;i<ss.length;i++){
                if(ss[i].isDirectory()){    
                    String currDir=ss[i].getAbsolutePath();
                    System.out.println("Total File & Directory "+ss.length);
                    this.getFiles(currDir);
                }else{                    
                    System.out.println("[F]\t"
                            +getPermissions(ss[i].canRead(),ss[i].canWrite(),ss[i].canExecute())+
                            "\t"+                            
                            ss[i].getName());
                }
            }
        }else{            
            System.out.println("Unable to read");
        }
    
    }
    /**
     * Checks for the access in files
     * @param canRead
     * @param canWrite
     * @param canExecute
     * @return 
     */
    private String getPermissions(boolean canRead, boolean canWrite,
            boolean canExecute) {
        StringBuffer buff=new StringBuffer();
        if(canRead)
            buff.append("r");
        else
            buff.append("-");
        if(canWrite)
            buff.append("w");
        else
            buff.append("-");
        if(canExecute)
            buff.append("e");
        else
            buff.append("-");
        return buff.toString();
    }
    
    /**
     * Start of Program
     * @param args
     */
    public static void main(String args[]){
        FileStructure obj=new FileStructure();
        obj.getFiles(args[0]);
        
    }

}


/**
 * Class extends comparator to sort files and directories
 * @author Sudipta Kumar Laha
 *
 */
class sortStructure implements Comparator<File>{
    @Override
    public int compare(File o1, File o2) {
        // TODO Auto-generated method stub
        if(o1.isDirectory() && o2.isDirectory()){
            return o1.getName().compareTo(o1.getName());
        }else if(o1.isFile() && o2.isFile())
            return o1.getName().compareTo(o1.getName());
        else if(o1.isDirectory())
            return 1;
        else
            return 0;
    }    
}