Trading Engine Test Client

TradingEngineTestClient.java

import java.util.Date;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.net.URLConnection;
import java.util.Random;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;

public class TradingEngineTestClient implements Runnable {

    private static final String BASE_URL = "http://192.168.1.117:8082/training9_spring4-web";
    //private static final String BASE_URL = "http://192.168.1.117:3000";
    private static final int SALES_QUANTITY_FACTOR = 2;
    private static final long WAIT_TIME_AFTER_RUNNING = 50L;
    private static final int NUM_CONCURRENT_USERS = 30;
    private static final int NUM_PRODUCTS = 99;
    private static final int MAX_QUANTITY = 100;
    private static final int NUM_SELLERS = 500;
    private static final int NUM_BUYERS = 500;

	private static final double[] PRICES = {9.99};

	private final Random r = new Random();

	public static void main(String[] args) throws Exception {
		System.out.println("starting...");
		new TradingEngineTestClient().go();
		System.out.println("done!");
	}

    private ExecutorService pool = Executors.newFixedThreadPool(NUM_CONCURRENT_USERS); //lots of concurrent users!

	public void go() throws Exception {
		for(int i = 0; i < NUM_CONCURRENT_USERS; i++){
        	pool.execute(this);
		}
	}

	@Override
	public void run() {

		try{
			URL url = new URL(BASE_URL + "/sell2?productId=" + (r.nextInt(NUM_PRODUCTS)+1) +
                                                        "&quantity=" + SALES_QUANTITY_FACTOR * (1+r.nextInt(MAX_QUANTITY)) +
                                                        "&userId=seller-" + r.nextInt(NUM_SELLERS) +
                                                        "&price=" + PRICES[r.nextInt(PRICES.length)]);
			if(r.nextBoolean()){
				url = new URL(BASE_URL + "/buy2?productId=" + (r.nextInt(NUM_PRODUCTS)+1) +
                                                        "&quantity=" + (1+r.nextInt(MAX_QUANTITY)) +
                                                        "&userId=buyer-" + r.nextInt(NUM_BUYERS));
			}
            String reply = sendRequest(url, true);
            int i = reply.indexOf("\"id\":");
            int i2 = reply.indexOf(",", i);
            String id = reply.substring(i+5, i2).trim();
            System.out.println(id + ") " + url);
		}catch(Exception e){
			System.err.println(e);
		}finally{
            //resubmit the job
            pool.execute(this);
        }
	}

    private static String sendRequest(URL url, boolean waitAtEnd) throws Exception {
        URLConnection conn = url.openConnection();
        BufferedReader br = new BufferedReader(new InputStreamReader(conn.getInputStream()));
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        int current;
        try{
            while ((current = br.read()) != -1) {
                baos.write(current);
            }
        }finally{
            baos.close();
            br.close();
        }
        String reply = baos.toString();
        if(waitAtEnd) Thread.sleep(WAIT_TIME_AFTER_RUNNING);
        return reply;
    }

}