import java.io.FileWriter;
import java.util.ArrayList;

public class ThreadRunner {

	static class TestThread implements Runnable {

		private int threadNumber = 0;
		private int nFiles = 0;

		public void run() {
			for (int f = 0; f < nFiles; f++) {
				String fileName = outputFolder + "multi" + (threadNumber * nFiles + f) + ".txt";
				try {
					FileWriter fw = new FileWriter(fileName, false);

					for (long j = 0; j < numLines; j++) {
						fw.write(outStr);
					}
					fw.close();
				} catch (Exception ex) {
					ex.printStackTrace();
				}
			}

		}

		public TestThread(int num, int nFiles) {
			threadNumber = num;
			this.nFiles = nFiles;
		}

	}

	private static int numFiles = 60;

	private static int numThreads;

	private static final long numLines = 2000000;
	private static final String outStr = "123456789\r\n";
	private static final String outputFolder = "./dummyStuff";

	public static void multithread() throws InterruptedException {
		ArrayList<Thread> threads = new ArrayList<Thread>();
		for (int i = 0; i < numThreads; i++) {
			threads.add(new Thread(new TestThread(i, numFiles / numThreads)));
			threads.get(threads.size() - 1).start();
		}
		for (int i = 0; i < numThreads; i++) {
			threads.get(i).join();
		}
	}

	public static void singlethread() throws InterruptedException {
		for (int i = 0; i < numFiles; i++) {
			String fileName = outputFolder + "single" + i + ".txt";
			try {
				FileWriter fw = new FileWriter(fileName, false);
				// Write a lot of stuff
				for (long j = 0; j < numLines; j++) {
					fw.write(outStr);
				}
				fw.close();
			} catch (Exception ex) {
				ex.printStackTrace();
			}
		}
	}

	public static void main(String[] args) throws InterruptedException {
		for (numThreads = 1; numThreads <= 6; numThreads++) {
			long startTime = System.currentTimeMillis();
			multithread();
			// System.out.println("Multithreaded: " +
			// (System.currentTimeMillis() - startTime));
			long startTime2 = System.currentTimeMillis();
			singlethread();
			// System.out.println("Singlethreaded: " +
			// (System.currentTimeMillis() - startTime));

			System.out.println(
					numThreads + ": " + (startTime2 - startTime) + " vs. " + (System.currentTimeMillis() - startTime2));
		}

	}
}