The final exam for CPSC 225 is scheduled for 1:30 PM on Sunday, May 12.
The exam is cumulative, with some emphasis on material covered since the second test. The new material includes basic networking (Section 11.4); threads (parts of Sections 12.1–12.4, but not inlcuding 12.1.4, 12.1.5, 12.3.4, 12.3.5, 12.4.2, or 12.4.5); and from Chapter 13, just observable properties and the MVC pattern. JavaFX will not be on the text, except for the few topics from Chapter 13. See below for the full list of topics from the last part of the course that might be on the final exam.
You might want to also review the study guides for the two in-class tests, which you can find on the course web page or at http://math.hws.edu/eck/cs225/s19/test2info.html and http://math.hws.edu/eck/cs225/s19/test1info.html
The final exam is worth 20% of the grade for the course. It will be 6 pages long, with a format similar to other tests. You should expect one or two long, general essay questions at the end of the test.
The other remaining part of the course is the final project, which is worth 10% of the course grade. It is due on the last day of class, but will not actually be collected and printed until the afternoon of Tuesday, May 7. (However, we can discuss possible extensions to to this due date in class.) Your project should be submitted into a folder named final in your homework folder. You should be sure that the comment on your main class makes it completely clear how to use the program and what it is supposed to do.
Here are some terms and ideas covered since the second test:
computer networks
protocol
TCP/IP
IP: unreliable delivery of packets to a computer on the Internet
TCP: reliable, two-way communication between programs
host names and IP addresses
port numbers for TCP
the client/server model for networking with TCP
class Socket: one end of an open TCP connection
constructor: socket = new Socket(host,port)
socket.getInputStream()
socket.getOutputStream()
socket.close()
using a PrintWriter to send outgoing text over a network
using a Scanner to read incoming text over a network
class ServerSocket: listening for connection requests
constructor: listener = new ServerSocket(port)
listener.accept()
using listener.accept() in an infinite loop to handle multiple connections
network operations can block
writing simple clients and servers using Socket and ServerSocket
threads
how threads are similar to subroutines and how they differ
creating threads using subclasses of class Thread
creating a thread using the constructor new Thread(runnable)
starting a thread
using Thread.sleep(milliseconds) to pause the execution of a thread
using thread.join() to wait for the thread to terminate
InterruptedException (in Thread.sleep() or Thread.join())
race conditions
mutual exclusion
synchronized methods
the synchronized statement
the synchronization lock in every Object, and how it is used in synchronization
multiprocessing: dividing up a job among available processors
uses for threads:
animation (as an alternative to AnimationTimer)
background computation (for a responsive GUI during a long computation)
parallel processing (for speeding up computation)
dealing with blocking I/O (using a thread for network operations)
how threads can be used in a network server; and the advantage of using them
blocking queues
ArrayBlockingQueue<T> and LinkedBlockingQueue<T>
limited capacity blocking queues versus unlimited capacity blocking queues
the blocking operations queue.put(x) and queue.take() on a blocking queue
the producer/consumer pattern and how it is implemented using a blocking queue
thread pool
using a blocking queue to deliver tasks to threads in a thread pool
observable properties in JavaFX such as:
sldr.valueProperty() for a Slider
txt.textProperty() for a Label or TextField
btn.disableProperty() for a button
adding a listener to an observable property
binding a property to another property
design patterns
the Observer pattern and how it applies to observable properties
the MVC (Model-View-Controller) pattern
relationships among the model, the view, and the controller
Here are some of the most important topics from earlier in the term:
subclasses and extending classes; class hierarchies abstract classes and interfaces analysis of algorithms Big-Oh and Big-Theta notation worst case and average case run times run-time analysis of operations on stacks, lists, trees exceptions and exception classes throwing an exception checked exceptions and mandatory exception handling the full try..catch statement, including the finally clause recursion and recursive methods base case of a recursion infinite recursion examples of recursion such as maze-solving, blob-counting... linked data structures linked lists; traversing a linked list with a "runner" adding and deleting nodes in a linked list the "queue" and "stack" abstract data types operations on stacks and queues (push/pop and enqueue/dequeue) implementation of stacks and queues as linked lists implementation of stacks as arrays binary trees pre-order, in-order, post-order traversal of binary trees recursive processing of binary trees expression trees generic programming and generic classes in Java the JCF (Java Collection Framework) Collection, List, ArrayList, LinkedList, Set, TreeSet, HashSet for-each loops for traversing a collection Map, TreeMap, HashMap lambda expressions I/O streams input I/O stream versus output I/O stream binary I/O stream versus character I/O stream Scanner and PrintWriter files and the File class designing file formats
1. Write a Java code segment that will create a client Socket to connect to a server on math.hws.edu, port 20000. It should read one line of text from the server and output that line to System.out, then close the connection.
2. A class named WorkerThread is a subclass of Thread. Write a code segment that creates and starts ten threads of type WorkerThread. (Why might you want to create ten threads?)
3. Write a subclass of Thread to represent a thread that does nothing but output the numbers from 1 to 4, one number to a line. Then write commands to create and start two such threads. Describe the possible outputs that this could produce.
4. Explain the intent of the following code, explain why it can give an incorrect answer, and explain how it can be fixed so that the answer is guaranteed to be correct.
double sum = 0; // global variable!
static class Adder extends Thread {
int s;
Adder(int first) {
s = first;
}
public void run() {
double x = 0;
for (int i = s; i < s+100000; i++)
x = x + Math.sin(i);
sum = sum + x;
}
}
for (int i = 1; i < 1000000; i += 100000) {
Thread thread = new Adder(i);
thread.start();
}
5. You have this problem: Your GUI program uses a method double compute() to do a long computation. You don't want to call the method and wait for it to complete, since that would make your program hang for a long time. You decide that the method should be run in a separate thread. Write a subclass of Thread to execute the compute() method. Your class should have some way to get the return value from compute() back to the program after the computation has completed. Also, write a few sentences to explain what you have done.
6. Threads and parallel processing are becoming increasingly important in modern computer programming. Explain why, and describe at least two different reasons for using threads in Java.
7. What is meant by a blocking queue? How might one be used?
8. Suppose that bttn is a Button and box is a CheckBox. Explain what is accomplished by the following statement:
bttn.disableProperty().bind( box.selectedProperty() );
9. Show how to accomplish the same thing as the previous problem, using a listener instead of binding.
10. The Model-View-Controller architecture is one of the most important design patterns in computer science. Explain what it is, how it is used in Java, and what advantages it offers. What is meant by the "model," the "view," and the "controller?"