test 

  1 package book.jcp.ch10.avail;
  2 
  3 import java.util.Random;
  4 import java.util.concurrent.TimeUnit;
  5 
  6 public class TryLockDemonstrateDeadLock {
  7 
  8     private final static int NUM_THREADS = 20;
  9     private final static int NUM_ACCOUNTS = 5;
 10     private final static int NUM_ITERATIONS = 1000000;
 11 
 12     private static boolean transferMoney(Account fromAccount,
 13             Account toAccount, Long amount, long timeout, TimeUnit timeUnit)
 14             throws InsufficientFundsException, InterruptedException {
 15 
 16         long fixedDelay = getFixedDelayComponentNanos(timeout, timeUnit);
 17         long randMod = getRandomDelayModulusNanos(timeout, timeUnit);
 18         long stopTime = System.nanoTime() + timeUnit.toNanos(timeout);
 19 
 20         while (true) {
 21             if (fromAccount.lock.tryLock()) {
 22                 try {
 23                     if (toAccount.lock.tryLock()) {
 24                         try {
 25                             if (fromAccount.getBalance().compareTo(amount) < 0) {
 26                                 throw new InsufficientFundsException();
 27                             } else {
 28                                 fromAccount.debit(amount);
 29                                 toAccount.credit(amount);
 30                                 return true;
 31                             }
 32                         } finally {
 33                             toAccount.lock.unlock();
 34                         }
 35                     }// if
 36                 } finally {
 37                     fromAccount.lock.unlock();
 38                 }
 39             }// if
 40 
 41             if (System.nanoTime() < stopTime) {
 42                 return false;
 43             }
 44             TimeUnit.NANOSECONDS.sleep(fixedDelay + new Random().nextLong()
 45                     % randMod);
 46         }// while
 47 
 48     }
 49 
 50     private static long getFixedDelayComponentNanos(long timeout,
 51             TimeUnit timeUnit) {
 52         // TODO Auto-generated method stub
 53         return 0;
 54     }
 55 
 56     private static long getRandomDelayModulusNanos(long timeout,
 57             TimeUnit timeUnit) {
 58         // TODO Auto-generated method stub
 59         return 0;
 60     }
 61 
 62     public static void main(String[] args) {
 63         final Random rand = new Random();
 64         final Account[] accounts = new Account[NUM_ACCOUNTS];
 65 
 66         for (int i = 0; i < NUM_ACCOUNTS; i++) {
 67             accounts[i] = new Account();
 68         }
 69 
 70         class TransferThread extends Thread {
 71             @Override
 72             public void run() {
 73                 for (int i = 0; i < NUM_ITERATIONS; i++) {
 74                     System.out.println("-------------------" + "[ThreadId : "
 75                             + currentThread().getId() + " Iteration : " + i
 76                             + "]-------------------");
 77                     int fromAccount = rand.nextInt(NUM_ACCOUNTS);
 78                     int toAccount = rand.nextInt(NUM_ACCOUNTS);
 79                     Long amount = Math.abs(rand.nextLong() % 10000);
 80                     try {
 81                         transferMoney(accounts[fromAccount],
 82                                 accounts[toAccount], amount, 10,
 83                                 TimeUnit.MICROSECONDS);
 84                     } catch (InsufficientFundsException e) {
 85                         e.printStackTrace();
 86                     } catch (InterruptedException e) {
 87                         // TODO Auto-generated catch block
 88                         e.printStackTrace();
 89                     }
 90 
 91                 }
 92             }
 93         }
 94 
 95         for (int i = 0; i < NUM_THREADS; i++) {
 96             new TransferThread().start();
 97         }
 98     }
 99 
100 }

 

posted @ 2014-08-26 17:33  达度  阅读(206)  评论(0)    收藏  举报