Concurrent Programming, JAVA Programming

Assignment Help:
Problem 1
A savings account object holds a non-negative balance, and provides deposit(k )
and withdraw(k ) methods, where deposit(k ) adds k to the balance, and
withdraw(k ) subtracts k, if the balance is at least k, and otherwise blocks until
the balance becomes k or greater. getbalance() gives the current balance.
1. Implement this savings account using locks and conditions (use
java.util.concurrent.locks.ReentrantLock). Test by using the 3
functions.
2. Now suppose there are two kinds of withdrawals: ordinary and preferred.
Devise an implementation that ensures that no ordinary withdrawal occurs
if there is a preferred withdrawal waiting to occur.

Problem 2
Consider the following conditions: An enqueuer waiting on a full-queue or
a dequeuer waiting on an empty queue sleep indefinitely, unless woken up by
another thread. A thread must send a signal ONLY when it adds an element
to an empty queue or removes an element from a full-queue.
1. Implement a bounded partial queue using a signaling mechanism that
signals to all waiting dequeuers.
2. Implement the bounded partial queue by using a signaling mechanism
(your own scheme) that signals to only one waiting dequeuer or enqueuer,
and ensure that the lost-wake-up problem does not happen.


Problem 3
We have n threads, each of which executes method foo() followed by bar().
We want to add synchronization to ensure that no thread starts executing bar()
until all threads have finished executing foo(). To achieve this, we will insert
some barrier code between the two methods. Implement the following two
schemes for barrier code:
• Use a shared counter protected by test-and-test-and-set lock. Each thread
locks the counter, increments it, releases the lock, and repeatedly reads
the counter until it reaches n.
• Use an n-element Boolean array A. Initially all entries are 0. When thread
0 executes its barrier, it sets b[0] to 1, and repeatedly reads b[n - 1]
until it becomes 1. Every other thread i, repeatedly reads b[i - 1] until
it becomes 1, then it sets b[i] to 1, and repeatedly reads b[n - 1] until
it becomes 1.
Implement both these schemes in Java. Each of the methods foo() and
bar() just sleeps for 20 milliseconds. Test the two schemes for n = 16. Run
each scheme at least ten times, measure the total runtime in each test run,
discard the highest and lowest values, take the average, and use it to compare
the two schemes. Which performs better? Can you explain the reason? You
can run the experiments on ecen5033.colorado.edu. Submit the code as well as
experimental results.

Related Discussions:- Concurrent Programming

Point of Sale Terminal, The problem statement is pretty simple. We need a s...

The problem statement is pretty simple. We need a software implementation of a Point of Sale terminal at a typical store. The users of the system are the cashiers sitting at the sa

Explain jsp technology?, Java Server Page is a standard Java extension that...

Java Server Page is a standard Java extension that is described on top of the servlet Extensions. The goal of JSP is the simplified formation and management of dynamic Web pages. J

Synchronization and its importance, What do you mean by synchronization an...

What do you mean by synchronization and its importance?

Java web services, #quThis project is based on the teams example of chapter...

#quThis project is based on the teams example of chapter 1. Instead of teams, you will consider employees working in a department in a company. (Departments and employees are ana

Explain nested classes (or outer and inner classes) in java?, In Java not a...

In Java not all classes must be described separate from each other. You may put the definition of one class under the definition of another class. The class inside class is called

Explain drawing rectangles in java, Explain Drawing Rectangles in java ? ...

Explain Drawing Rectangles in java ? Drawing rectangles is easy. Begin with a Graphics object g and call its drawRect() method: public void drawRect(int x, int y, int width, i

Flash games, have some assignments and i want help with them. thanks

have some assignments and i want help with them. thanks

What is bandwidth, What is bandwidth? In a general way Bandwidth is a c...

What is bandwidth? In a general way Bandwidth is a capacity of communication channel of carrying data.

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd