simple transaction using synchronization
//the key to synchronization is the concept of minitor(semaphore).a monitor is an object that
//is used to mutually exclusive lock or mutex.
//this example uses synchronized methods
class balance
{
private int amount;
balance(int n)
{
amount=n;
}
//if a method is synchronized then only one thread can enter it the others have to wait
//remove this synchronized key word and check what happens and use it
synchronized void withdraw(int n)
{
if(amount>n)
{
try{
Thread.sleep(1000);
}catch(InterruptedException ie){}
amount=amount-n;
}
}
void display()
{
System.out.println(amount);
}
}
class counters implements Runnable
{
Thread t;
int draw;
balance b;
counters(String s,balance temp,int d)
{
draw=d;
b=temp;
t=new Thread(this,s);
t.start();
}
public void run()
{
b.withdraw(draw);
b.display();
}
}
class Sync
{
public static void main(String s[])
{
balance b=new balance(1000);
//create the counter objects one by one
counters c1=new counters("counter1",b,100);
//counters c2=new counters("counter2",b,500);
//counters c3=new counters("counter3",b,600);
}
}
output:
900
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