Programming

import java.io.File;
import java.util.Date;

class LastFile{
    File directory;

    LastFile(String directoryPath){
        File directory=new File(directoryPath);
        this.directory=directory;
    }

    public String getLast(){
        File[] fileList=this.directory.listFiles();
        Date now= new Date(); //asumes current locale in use in file store
        long last_mod_date=now.getTime();
        String oldestFile = "";
        for (int i = 0; i < fileList.length; i++){
            if (fileList[i].lastModified() < last_mod_date){
                oldestFile = fileList[i].getPath();
                last_mod_date = fileList[i].lastModified();
            }
        }
        return(oldestFile);
    }

    /***
    * Quick and dirty test of class if called directly rather than imported
    * This is no substitute for proper testing, just a handy way to test 
    * one off projects.
    ***/
    public static void main(String[] args){
        if (args.length > 0){
            for (int i = 0;i<args.length;i++){
                LastFile last = new LastFile(args[i]);
                System.out.println( "The last modified file in the directory "
                + args[i] + " is " + last.getLast());
            }
        }
        else{
            LastFile last = new LastFile(".");
            System.out.println( "The last modified file in the directory \".\" is " 
            + last.getLast());
        }
    }
}

    public String getLargestId(){
        File[] fileList=this.directory.listFiles();
        int largestFileId=0;
        String largestFile="";
         for (int i =0; i<fileList.length; i++){
            String filename=fileList[i].getPath();
            int fileId=getFinalDigits(filename);
            if ( fileId > largestFileId){
                largestFileId=fileId;
                largestFile=filename;
            }
        }
        return largestFile;
    }
    /**
    * You should of course catch any possible runtime exceptions
    * Check out the JavaDocs on the regex library
    **/
    private static int getFinalDigits(String filename){
        Pattern p = Pattern.compile("\\d+$");
        Matcher m = p.matcher(filename);
        return Integer.parseInt(m.group(0));
    }