Question

Use the Java implementation of transaction()

public void transaction(Account from, Account to, double amount) {

mutex lock1, lock2;

lock1 = get_lock(from);

lock2 = get_lock(to);

acquire(lock1);

acquire(lock2);

withdraw(from, amount);

deposit(to, amount);

release(lock2);

release(lock1);

}

The code does not need to have "Driver" (main method) to execute. Also use "Synchronized() method in Java" which provides exclusive access to an object (i.e., from Account or to Account in the transaction).

Could you write the code please?

Example of Synchronized() method (not my code):

// An alternate implementation to demonstrate

// that we can use synchronized with method also.

class Sender

{

    public synchronized void send(String msg)

    {

        System.out.println("Sending\t" + msg );

        try

        {

            Thread.sleep(1000);

        }

        catch (Exception e)

        {

            System.out.println("Thread interrupted.");

        }

        System.out.println("\n" + msg + "Sent");

    }

}

Answer 1

public void transaction(Account from, Account to, double amount) {

mutex lock1, lock2;

lock1 = get_lock(from);

lock2 = get_lock(to);

acquire(lock1);

acquire(lock2);

synchronized(lock1){

synchronized(lock2){

withdraw(from, amount);

deposit(to, amount);
}
}
release(lock2);

release(lock1);

}

So i have added synchronized so that threads whcih has lock1 and lock2 will be able to perform the withdraw and deposit functions