lockdemo.java

Java面向对象编程(随书配套源代码) 阐述了面向对象编程的思想

package chapter10;
public class LockDemo implements Runnable 
{
	protected CustomerAccount fromAccount;
  	protected CustomerAccount toAccount;
  	protected int transferCount;
  	public LockDemo(CustomerAccount fromacct,CustomerAccount toacct, int transfers) 
  	{
  	  	fromAccount = fromacct;
    	toAccount = toacct;
    	transferCount = transfers;
  	}
  	public void run() 
  	{
    	double balance;
    	double transferAmount;
    	for (int i = 0 ; i < transferCount; i++) 
    	{
      	synchronized (fromAccount) 
      	{
        	balance = fromAccount.getBalance();
        	transferAmount = (int)(balance * Math.random());
        	balance -= transferAmount;
        	fromAccount.setBalance(balance);
        	synchronized (toAccount) 
        	{
          		balance = toAccount.getBalance();
          		balance += transferAmount;
          		toAccount.setBalance(balance);
        	}
      }
    }
  }
}