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Hi everyone,
I would be grateful if someone help me with next problem that i have in Java:
Thing that i want to do is to make client-server chat app on web. I am using RMI. I will show just important class for my problem..
Here is mu server interface:
<pre lang="java">public interface ChatServerIF extends Remote {
//void registerChatClient(ChatClientIF chatClient) throws RemoteException;
//void broadcastMessage(String message) throws RemoteException;
void registerClient(String ime, ChatClientIF chatKlijent) throws RemoteException;
void posaljiPoruku(String ime, String poruka) throws RemoteException;
void dodajWeb(String naziv, PrintWriter print) throws RemoteException;
void pronadjiWeb(String naziv) throws RemoteException;
}
server class:
public class ChatServer extends UnicastRemoteObject implements ChatServerIF {
public static final long serialVersionUID = 1L;
private HashMap<String, ChatClientIF> hmap = new HashMap<String, ChatClientIF>();
private Map<String, PrintWriter> web = new HashMap<String, PrintWriter>();
public List<HttpServletResponse> lista = new ArrayList<HttpServletResponse>();
public ChatServer() throws RemoteException{
}
@Override
public synchronized void dodajWeb(String naziv, PrintWriter print) throws RemoteException{
web.put(naziv, print);
}
@Override
public void pronadjiWeb(String naziv) throws RemoteException {
}
and part of servlet:
protected void processRequest(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;charset=UTF-8");
try (PrintWriter out = response.getWriter()) {
out.println("<!DOCTYPE html>");
out.println("<html>");
out.println("<head>");
out.println("<title>Servlet IgraServlet</title>");
out.println("</head>");
out.println("<body>");
String username = request.getParameter("username");
ChatServerIF chat = (ChatServerIF) request.getSession().getAttribute("server");
ChatClient cc = (ChatClient) request.getSession().getAttribute("klijent");
PrintWriter pw = (PrintWriter) request.getSession().getAttribute("out");
chat.dodajWeb(username, pw);
cc.run();
out.println("aaa");
out.println("<h1>Servlet IgraServlet at " + request.getContextPath() + "</h1>");
out.println("</body>");
out.println("</html>");
}
My idea is to store user and PrintWritter for that user, from web page on server in order i can later sent message to that client.
Am i thinking good, or completely wrong?
But problem comes when i call chatServer interface method on servlet "chat.dodajWeb(username, pw)" i got next error:
java.rmi.MarshalException: error marshalling arguments; nested exception is:
java.io.NotSerializableException: java.io.PrintWriter
Please help me i try to search solution on internet, but for now without result..
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plz help us to create intranet mailing system project using java and the platform is netbeans plz give us software and code for create this project.
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Sorry no, this site does not provide code to order. Also, since it is supposed to be your project then you are expected to do the work.
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1. Sorted Names – Write a program that asks the user to enter 10 last names (the names of every student in our class) and then displays the names sorted in ascending order. For example, if the user entered “Charlie” “Leslie” and “Andy” the program would display: Andy, Charlie, Leslie
2.. An internet service provider has 3 different packages.
A: For $9.95 per month 10 hours of access are provided. Additional hours are $2.00/hour
B: For $13.95 per month 20 hours of access are provided. Additional hours are $1.00/hour
C: For $19.95 per month unlimited access is provided
Write a program that calculates a customer’s monthly bill. It should ask the user to enter the letter of the package the customer has purchased (A, B, or C) & the number of hours that were used. It should display the total charges
3. 3. Bank Charges: A bank charges a base fee of $10 per month, plus the following check fees for a commercial checking account.
$.10 each for less than 20 checks
$.08 each for 20-39 checks
$.06 each for 40-59 checks
$.04 each for 60+ checks
Write a program that asks for the number of checks written for the month. The program should then calculate and display the bank’s service fees for the month.
Any help with this would be greatly appreciated!
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Member 12074376 wrote: Any help with this would be greatly appreciated
Then you need to explain what help you want. If you are expecting someone else to write the code for you then I am afraid you are out of luck.
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Your homework is set to test what you know, not what a bunch of random strangers on the Internet know.
Try writing the code yourself. If you genuinely can't get started, then talk to your teacher. Nobody here is going to do your homework for you.
"These people looked deep within my soul and assigned me a number based on the order in which I joined."
- Homer
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What have you done so far, where are you having trouble with it? Or are you just waiting for someone to do the assignment for you?
"I've seen more information on a frickin' sticky note!" - Dave Kreskowiak
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I have been told a Binary search tree can be used with a Bag class. I can see the picture of it in my head, but not sure how it would convert to Code? Any input would be great!
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Member 12050371 wrote: I have been told
Then you should ask that person for clarification.
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i want that u suggest me a book for beginners of java   .. please you can suggest any types of notes also.  . and what is easy and simpler font chooser code ??  thankuuu ![Rose | [Rose]](https://www.codeproject.com/script/Forums/Images/rose.gif) 
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Hello All,
I am a current college student that is back in school for a second career. I am well behind the curve (48 yrs old.) as far as programming is concerned, so every minute I spend wasted is one more that I fall behind.
I know that I am probably opening up a Pandora’s box, but I have heard about the certifications but yet I cannot find much information – such as which ones are the important certifications to have. If you could start it over and do your learning, training again – How would you do it? I wanted to ask those in the field, as none of my friends are in the field.
Any help would be greatly appreciated.
Matt
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Certifications do not necessarily have great value, as most employers are looking for people with experience, or a college/university degree. And which subject to choose is always a difficult question to answer, as it depends on your interests and the requirements of the job market that you are targeting. You should talk to your professor about it as (one hopes) he/she has a good understanding of the market.
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Am trying to make a java program that displays random letters till the letters make one of the words at, is, he, we, up, or on. I think am on the right track, just not sure how to stop when i reach one of those words. This is what i have so far.
public class main {
public static void main (String[] args) {
final int NUMBER_OF_CHARS = 100000;
String[] words = {"at","is","he","we","up","on"};
for (int i = 0; i < NUMBER_OF_CHARS; i++) {
char ch = main.getRandomLowerCaseLetter();
if ((i + 1) % 40 == 0)
System.out.println(ch);
else
System.out.print(ch);
}}
public static char getRandomCharacter(char ch1, char ch2) {
return (char)(ch1 + Math.random() * (ch2 - ch1 + 1));
}
public static char getRandomLowerCaseLetter() {
return getRandomCharacter('a', 'z');
}}
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Just add some logic inside your loop to check every two characters to see if they match any of the words in the list. This would mean another loop that iterates through that list and does a string comparison[^] with your new 'word'.
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hi
i am trying to use java to iterate thru the window desktop element.
does anyone know the API in java?.
i would like to print out in java the whole tree of my current desktop GUI elements.
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Hi! I've been trying to implement Markov's algorithm, but I've only had partial success. The algorithm is fairly simple and can be found here.
However, my project has an added difficulty, I have to use rules that include markers and variables.
A variable represents any letter in the alphabet and a marker is simply a character that is used as a reference to move the variables around (It doesn't have a real value).
This example duplicates every character in a string:
Alphabet: {a,b,c}
Markers: {M}
Variables: {x}
Rule 1: Mx -> xxM
Rule 2: xM -> x
Rule 3: x -> Mx
input: abc
abc //We apply rule 3
Mabc //We apply rule 1
aaMbc //We apply rule 1
aabbMc //We apply rule 1
aabbccM //We apply rule 2
aabbcc
This is my recursive function that implements a markov algorithm that only works with string inputs for example: Rule 1: "apple" -> "orange", Input: "apple".
public static String markov(String input, LinkedList<Rule> rules) {
for (Rule rule : rules) {
if (!input.equals(input.replace(rule.getFrom(), rule.getTo()))) {
if (rule.isTerminating()) {
input = input.replaceFirst(Pattern.quote(rule.getFrom()), rule.getTo());
System.out.println(input);
return input;
} else {
input = input.replaceFirst(Pattern.quote(rule.getFrom()), rule.getTo());
System.out.println(input);
return markov(input, rules);
}
}
}
return input;
}
I can't figure out how to implement variables and markers into this logic so perhaps someone can educate me on the best way to implement this logic? any advice is welcome.
Thank You!
GitHub
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A type of coffee.
If you can find your way to CodeProject, then you should be able to find your way to Google, for such an elementary question. Or try your local library/bookstore.
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I need to do a program with 2d array.
- it should ask the amount of columns and rows from the user
- print the array
- add numbers 1,2,3...
- print the array
- calculate every rows averige and print it after the row
- calculate every columns sum and print it after the column
Here is what i have (after two days  )
import java.util.Scanner;
public class matrix {
private static Scanner scanner;
public static void main(String[] args) {
scanner = new Scanner(System.in);
System.out.println ("Create matrix AxB");
System.out.println ("Set rows (A)");
int A = Integer.parseInt(scanner.nextLine());
System.out.println("A = " + A);
System.out.println(" ");
System.out.print("Set columns (B)");
int B = Integer.parseInt(scanner.nextLine());
System.out.println("B = " + B);
System.out.println(" ");
int X = A * B;
int[][] matrix = new int[A][B];
for (int row=0; row<matrix.length; ++row)
for (int column=0; column<matrix[row].length; ++column) {
System.out.println("Set element "+row+", "+column);
matrix[row][column] = scanner.nextInt();
}
System.out.println("Your matrix:");
for (int row=0; row<matrix.length; ++row) {
for (int column=0; column<matrix[row].length; ++column)
System.out.print(matrix[row][column]+"\t");
System.out.println();
}
}
}
So Please someone help me 
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OK, that seems to work quite well, so all you need is to add the calculations of the averages and sums. You can do these as you print the rows and columns, althugh you will need an extra array for the column sums, and a variable for the averages. Something like:
int[][] matrix = new int[A][B];
int sums[] = new int[B];
int average;
for (int row=0; row<matrix.length; ++row)
for (int column=0; column<matrix[row].length; ++column) {
System.out.println("Set element "+row+", "+column);
matrix[row][column] = scanner.nextInt();
}
System.out.println("Your matrix:");
for (int row=0; row<matrix.length; ++row) {
average = 0;
for (int column=0; column<matrix[row].length; ++column) {
System.out.print(matrix[row][column]+"\t");
average += matrix[row][column];
sums[column] += matrix[row][column];
}
System.out.println("- average: " + (average / B));
}
for (int column=0; column<matrix[0].length; ++column) {
System.out.print("----\t");
}
System.out.println();
for (int column=0; column<matrix[0].length; ++column) {
System.out.print(sums[column]+"\t");
}
System.out.println();
}
You could also improve the accuracy of the averages by using a float type rather than integer.
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