piggybankwithsync.java

一个基于JADE的多AGENT问题

/**
 * PiggyBankWithSync.java: 
 * - Demonstrate avoiding resource conflict
 */


public class PiggyBankWithSync 
{
  private PiggyBank bank = new PiggyBank();
  
  //Create array for 100 threads
  private Thread[] thread = new Thread[100];

  
  public PiggyBankWithSync() 
  {
    //Create a thread group in which all 100 threads are to be executed
    ThreadGroup g1 = new ThreadGroup("group");
    boolean done = false;

    // Create and start 100 threads  
    for (int i = 0; i < 100; i++) 
    {
      //Arguments below are: (Thread Group, the Thread Object, name of thread) 
      thread[i] = new Thread(g1, new AddAPennyThread(), "t");
      thread[i].start();
    }

    // Check that every thread have finished their execution
    while(!done)
    {
      //Estimate number of active threads in the thread group
      if (g1.activeCount() == 0)
      {   
        done = true;
      }
    }
  }

  //a synchronised method used for adding one coin at the time
  private static synchronized void addAPenny(PiggyBank bank) 
  {
    //Check current balance in the piggy bank and add a coin
    int newBalance = bank.getBalance() + 1;

    try {
      Thread.sleep(5); //Executing thread sleeps for a while :-)
    }
    catch (InterruptedException ex) 
    {
      System.out.println(ex);
    }

    //Update balance including the recently added coin 
    bank.setBalance(newBalance);
  }
  /*******************************************
  * A thread for adding a penny to the piggy bank
  ****************************************/
  private class AddAPennyThread extends Thread 
  {
    public void run() 
    {
      addAPenny(bank);
    }
  }  
  public static void main(String[] args) 
  {
    PiggyBankWithSync test = new PiggyBankWithSync();
    System.out.println("Using a synchronized method:\n- What is the balance?\n\tThe piggy bank contains " + test.bank.getBalance()+" coins\n");
  }


}