Main.java

import java.io.*;
import java.math.BigInteger;
import java.security.SecureRandom;
import java.text.SimpleDateFormat;
import java.util.Date;

/**
 * @author <a href="http://www.joshuaslik.nl/" target="_blank">Joshua Slik</a>
 */
public class Main {
	
	private static String filename = "Words";
	private static int wordnumber = 171476; // Estimate of the number of different words currently in use in the Oxford dictionary
	private static SecureRandom random = new SecureRandom();
	
	public static void main(String[] args) throws InterruptedException {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSS");
		long timeStart, timeStop, timeDiff;
		
		System.out.println("Time at start of file generation : " + sdf.format(new Date()));
		timeStart = System.nanoTime();
		makeFile();
		timeStop = System.nanoTime();
		timeDiff = timeStop - timeStart;
		System.out.println("Time at end of file generation   : " + sdf.format(new Date()));
		System.out.println("Time elapsed during generation   : " +
								   timeDiff + " nanoseconds / " +
								   Math.round((timeDiff / 1e6) * 1000.0) / 1000.0 + " milliseconds / " +
								   Math.round((timeDiff / 1e9) * 1000.0) / 1000.0 + " seconds.");
		
		System.out.println("Waiting a bit");
		Thread.sleep(3000);
		
		System.out.println("Time at start of file iteration  : " + sdf.format(new Date()));
		timeStart = System.nanoTime();
		iterate();
		timeStop = System.nanoTime();
		timeDiff = timeStop - timeStart;
		System.out.println("Time at end of file iteration    : " + sdf.format(new Date()));
		System.out.println("Time elapsed during iteration    : " +
								   timeDiff + " nanoseconds / " +
								   Math.round((timeDiff / 1e6) * 1000.0) / 1000.0 + " milliseconds / " +
								   Math.round((timeDiff / 1e9) * 1000.0) / 1000.0 + " seconds.");
	}
	
	public static void makeFile() {
		File output = new File(filename);
		FileWriter fw = null;
		
		try {
			fw = new FileWriter(output);
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (fw == null) {
			return;
		}
		
		for (int i = 0; i <= wordnumber; i++) {
			try {
				fw.write(new BigInteger(32, random).toString(32));
				fw.write(String.format("%n"));
				//System.out.println("Printed " + i);
			} catch (IOException e) {
				e.printStackTrace();
			}
			//System.out.println(i);
		}
		try {
			fw.flush();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public static void iterate() {
		File input = new File(filename);
		File output = new File(filename + " copy");
		FileWriter fw = null;
		BufferedReader br = null;
		
		try {
			fw = new FileWriter(output);
		} catch (IOException e) {
			e.printStackTrace();
		}
		if (fw == null) {
			return;
		}
		
		try {
			br = new BufferedReader(new FileReader(input));
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		if (br == null) {
			return;
		}
		
		try {
			String line;
			while ((line = br.readLine()) != null) {
				try {
					fw.write(line);
					fw.write(String.format("%n"));
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
		
		try {
			fw.flush();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
}