Objects First with Java: A Practical Introduction Using BlueJ (6th Edition)
6th Edition
ISBN: 9780134477367
Author: David J. Barnes, Michael Kolling
Publisher: PEARSON
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Textbook Question
Chapter 3, Problem 42E
Open the mail-system project, which you can find in the book's support material. The idea of this project is to simulate the act of users sending mail items to each other. A user uses a mail client to send mail items to a server, for delivery to another user's mail client. First create a Mail Server object. Now create a Mai1C1ient object for one of the users. When you create the client, you will need to supply a Mail Server instance as a parameter. Use the one you just created. You also need to specify a username for the mail client. Now create a second MailClient in a similar way, with a different username.
Experiment with the MailCIient objects. They can be used for sending mail items from one mail client to another (using the sendMai1 Item method) and receiving messages (using the getNextMailItem or printNextMailItem methods).
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Implement a simple e-mail messaging system.
I have already designed a Message class and a Mailbox/MailboxTest class. A message has a recipient, a sender, and a message text. A Mailbox can store and manipulate messages and tell the user how many they have.
Supply a number of mailboxes for different users and a user interface(GUI) for the user to login, send messages to other users, read their own messages, and log out.
Please explain each thing you do.
Here is my Message class:
publicclass Message
{
private String recipient;
private String sender;
private String messageBody;
public Message(Stringsender, String recipient) {
this.sender =sender;
this.recipient =recipient;
this.messageBody ="";
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public void append(String text) {
this.messageBody +=text +"\n";
}
public String toString() {
return "From: " + this.sender+ "\n" + "To: " + this.recipient + "\n" + "Message: " + this.messageBody;
}
}
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import java.util.ArrayList;
publicclass Mailbox{
private…
Copy and rename SimplApp.java; then modify it to create a GUI program that accepts a String from the user in a TextField and reports whether or not there are repeated characters in it. Thus your program is a client of the class which you created in question 1 above. N.B. most of the modification needs to occur in the constructor and the actionPerformed() methods. So you should spend time working out exactly what these two methods are doing, so that you can make the necessary modifications.
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Chapter 3 Solutions
Objects First with Java: A Practical Introduction Using BlueJ (6th Edition)
Ch. 3 - Prob. 1ECh. 3 - At what time (s) can a class diagram change? How...Ch. 3 - At what time(s) can an object diagram change? How...Ch. 3 - Write a definition of a field named tutor that can...Ch. 3 - Prob. 5ECh. 3 - Create a second NumberDisplay object with a limit...Ch. 3 - Select Show Code Pad from the View menu. Create a...Ch. 3 - What error message do you see in the Code Pad if...Ch. 3 - What error message do you see in the Code Pad if...Ch. 3 - What happens when the setValue method is called...
Ch. 3 - Prob. 11ECh. 3 - Prob. 12ECh. 3 - Which of the following expressions return...Ch. 3 - Write an expression using boolean variables a and...Ch. 3 - Write an expression using boolean variables a and...Ch. 3 - Consider the expression (a && b). Write an...Ch. 3 - Does the getDisplayValue method work correctly in...Ch. 3 - Prob. 18ECh. 3 - In Exercise 2.79 you were asked to investigate...Ch. 3 - Explain the modulo operator. You may need to...Ch. 3 - What is the result of the expression 83?Ch. 3 - Try out the expression in the Code Pad. Try other...Ch. 3 - Prob. 23ECh. 3 - Prob. 24ECh. 3 - Explain in detail how the increment method works.
Ch. 3 - Rewrite the increment method without the modulo...Ch. 3 - Open the clock-display project and create a...Ch. 3 - Prob. 28ECh. 3 - Prob. 29ECh. 3 - Prob. 30ECh. 3 - Look at the second constructor in C1ockDisplay's...Ch. 3 - Prob. 32ECh. 3 - Given a variable Printer p1; which currently holds...Ch. 3 - Open the house project from Chapter 1 and review...Ch. 3 - Prob. 35ECh. 3 - Does the Picture class contain any internal method...Ch. 3 - Remove the following two statements from the draw...Ch. 3 - Prob. 38ECh. 3 - Prob. 39ECh. 3 - Assume a class Tree has a field of type Triangle...Ch. 3 - Prob. 41ECh. 3 - Open the mail-system project, which you can find...Ch. 3 - Prob. 43ECh. 3 - Prob. 44ECh. 3 - Open the editor for the MailClient class and set a...Ch. 3 - Step one line forward in the execution of the...Ch. 3 - Prob. 47ECh. 3 - Prob. 48ECh. 3 - Prob. 49ECh. 3 - Set a breakpoint in the first line of the sendMai1...Ch. 3 - Use a combination of code reading, execution of...Ch. 3 - Use the debugger to investigate the clock-display...Ch. 3 - Prob. 53ECh. 3 - Prob. 54ECh. 3 - Prob. 55ECh. 3 - Describe the changes that would be required to the...Ch. 3 - Write the code for the timeTick method in...Ch. 3 - Discuss whether the current design of the...Ch. 3 - Challenge exercise In the current design of...
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