Creating Three Exception Classes
Sep 28, 2014
Why I have to place two parameters in the Verify constructor. If the numbers are being typed in by the user and passed through the validate method, what is the point of having them in Verify() ?
First, create three exception classes named NumberHighException, NumberLowException, and NumberNegativeException. Both NumberHighException and NumberLowException should be directly subclassed from the Exception class, but NumberNegativeException should be subclassed from NumberLowException. You can use the BadDataException class that was defined in this module as the model for your exception classes.
Next create a class called Verify that will be used to validate that a number is within a specified range. It should have one constructor that has two int parameters. The first parameter is the minimum number in the range, and the second parameter is the maximum number in the range.
In addition to the constructor, the Verify class should have one method that is named validate. The validate method should have a single parameter of data type int. The parameter contains the number that is being validated. If the value of the parameter is less than zero, the method should throw a NumberNegativeException. If the value is less than the minimum value of the range, it should throw a NumberLowException. If the value is greater than the maximum value of the range, it should throw a NumberHighException. If the value is within the specified range, no exception should be thrown.
Once all of these classes are created, create the driver class called Program5. The driver class should instantiate a Verify object with a range of 10 to 100. It should then do the following:
-Prompt the user to input a number within the specified range.
-Use a Scanner to read the user input as an int. You can ensure that an int was entered because the nextInt method throws an --InputMismatchException if any non-digits are entered.
-Call the validate method to validate that the number is within the range.
-Print an appropriate error message if the value is not within the range, or print the value if it is within the range.
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Apr 25, 2014
I was trying to play around a little bit after learning creating multiple classes and stuff.However,i encountered a strange problem with reading a value from the user and then storing it in a variable.The usual way i do it is
Scanner variableName=new Scanner(System.in);
System.out.println(variableName.nextLine());
But when i trying to print the contents of the variable "variableName" the compiler throws a lot of errors .I am attaching how i have tried that out in my code
import java.util.Scanner;
class laptop{
private String modelNumber;
private boolean hasFan;
private float ramSpeed;
protected int numCores;
//private String input;
[code]....
Without the setInfo() in the laptop class the program functions as desired but i intend to ask the user if he wants to modify something and then reflect the same.
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Jan 23, 2014
I have two classes, where main class is simple with only main function in it. Another class extends Thread and there's couple of functions I want to execute from main class.
Problem: I try to get other.shut() to be run in main class catch() block, after I have stopped the other class's running thread (e.g. by ctrl+c).
I think I need to somehow "pass" the exception from other class to main class so it goes to the catch block?
Code for main class:
Java Code:
public class MainClass {
public static void main(String[] arguments) {
OtherClass other = new OtherClass();
try {
other.exec();
} catch (Exception e) {
other.shut();
[Code] .....
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Jul 20, 2014
I've been trying to work with custom Exception classes, but I keep running into what I think is an array error. It's in a very monolithic format because I was just trying to bang it out and get it done. Anyway, my issues is I am trying to compare values in the array to the minimum and maximum possible scores for a student (0 and 100) but I have totally forgotten how to do it.
Here is the code, the offending bit is at the very bottom:
package org.CIS407.Lab6;
import java.util.*;
public class TestScore {
public static void main(String[] args) throws ScoreException {
Scanner scan = new Scanner(System.in);
int sz; //holds scanner values
int[] studentArray;
[Code] .....
Right now I'm getting an error when I go to enter the very last student score. It throws an exception.
Here is a sample output of what I'm getting:
Enter number of students
2
Array created successfully. Enter student ID's into array
1
2
Enter number of scores
2
Array created successfully. Enter student scores into the array
50
32
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 2
at org.CIS407.Lab6.TestScore.main(TestScore.java:64)
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Aug 15, 2014
The requirements are as follows:Design and implement the class Day that implements the day of the week in a program. The class Day should store the day, such as Sun for Sunday. The program should be able to perform the following operations on an object of type Day:
A. Set the day.
B. Print the day.
C. Return the day.
D. Return the next day.
E. Return the previous day.
F. Calculate and return the day by adding certain days to the current day. For example, if the current day is Monday and we add four days, the day to be returned is Friday. Similarly, if today is Tuesday and we add 13 days, the day to be returned is Monday.
G. Add the appropriate constructors.
H. Write the definitions of the methods to implement the operations for the class Day, as defined in A through G.
I. Write a program to test various operations on the class Day.Should I break down my day.java into several separate classes, one for each of the sections (previous, next, etc)?
import java.util.*;
public class MyDay
{
static Scanner readinput = new Scanner(System.in);
String day;
public MyDay(String day)
{
day = "Sunday";
[code]....
Ideally I would like to create a Gui that would have someone type in the day, and then press a button to return the next day, prior day, or have a text input to test for adding X number of days.
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Aug 31, 2014
I use Eclipse IDE
public class Emp {
private String name;
private String jobTitle;
public void setName(String nameIn){
name=nameIn;
[Code] ....
<terminated> TestClass
Exception in thread "main" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Unknown Source)
at TestClass.payOneEmp(TestClass.java:21)
at TestClass.main(TestClass.java:13)
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May 17, 2014
I created the below code and it works fine. It is a deck card game. I just want to divide my code into classes so that it seems more organized.
Java Code:
package getimage;
import java.awt.BorderLayout;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.GridLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.util.ArrayList;
import java.util.Collections;
import javax.swing.*;
[code]....
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Jan 22, 2014
What I'm doing about it: googling the shit out of my problems, consulting you fine readers, consulting my friends, and yesterday I signed up for Lynda.com. I'm hoping 30hrs+ or so of watching, rewatching, and analyzing the example code will catch me up before I get too behind in CS302
** Assignment Prompt **
Integer types are very convenient, but their limited width and precision makes them unsuitable for some applications where precision is more important than speed. Develop a class VeryLargeInteger that can handle arbitrary long integer numbers (both negative and positive) and the basic arith- metic operations (addition, subtraction, multiplication, division, and remainder).
Hint: The number could be represented as string, the sign could be represented either as boolean or as part of the string.
Note: Implementations of addition/subtraction through repeated use of a constant incremen- t/decrement will not be accepted. Implementations of multiplication and division that rely only on addition and subtraction will not be accepted.
I know I'm going to have to create a separate tester to call on the VeryLargeInteger class and it's math methods. For the new data type, should I convert the integer/string into an array in order to handle the large length of the number? I know he wants us to use recursion for the math methods. My gut tells me addition and subtraction will be slightly easier than multiplication and division. I know I'll have to reference the other methods for division. We aren't allowed to use the BigInteger class.
How I should construct any of the methods.
Java Code:
import java.util.ArrayList;
/**
∗ VeryLargeInteger (VLI) is a class for arbitrary precision integer computation
*/
public class VeryLargeInteger {
private int[] num1;
private int[] num2;
private int[] num3;
[code]....
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May 12, 2013
My situation deals with zero point... I have an issue where when my computer program equals zero, it starts to send a command to the camera and the camera ball starts going erratic. I want to try and refine the code so that when the camera goes to zero point, its initial stage or beginning before I apply functions to make it move, it goes to, say, (0,1) instead of (0,0) I think, after browsing google, the code segment:
if (Nadir=0)
zeropoint= true
then act ()
... move to (0,1)
I am assuming once the camera goes to its standby spot, (0,0) it reaches its zeropoint, and that makes the program divide by zero, thus making it erratic... I want to make it to where once it goes to its zeropoint, the program says, no, go here to prevent the error of dividing by zero... is it possible?
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Apr 10, 2014
I'm trying to have the program create a .txt file for me but it is not working properly. It just keeps printing the exception error "The file could not be found" and exits the program.
// This program asks the user for input for a name, phone number and notes up to 200 entries.
// It stores every contact in a file. Type 'h' for help while running this program.
import java.util.Scanner;
import java.io.*;
public class Phonebook {
static Entry[] entryList = new Entry[200];
static int numEntries;
public static void main(String[] args) {
[Code] ....
After running the code, I go into my workspace folder and I see that the file was created. What to do because running the program will always print "could not find the file".
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Feb 7, 2014
i want to list files from resources folder like this:
@ManagedBean
public class galley implements Serializable {
private List<String> list;
@PostConstruct
public void init() {
list = new ArrayList<String>();
[Code] ....
but it give me a null pointer exception on fList .... The directory of resources is :
How is this caused and how can I solve it?
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Jan 24, 2014
I was giving a quick skim to some tutorials on the internet where I have found the exception that is handled is also declared in the throws clause of the method wrapping the try-catch block. For a code representation consider the following:
public void methodName() throws IOException {
try {
...
} catch (IOException ex) {
.... TODO handle exception
}
}
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Apr 18, 2014
How do you call classes within other classes? Or can you only call classes through the main?
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Sep 29, 2014
Right, so I got this program. It takes input from the user and assigns it to fields on an object. But, it's meant to check the users input. If the user enters bad input, it's supposed to throw this exception. For each of these exceptions, theres a class specifically for it.
public class PayrollDemo
{
public static void main(String[] args)
{
Payroll pr = new Payroll ("Test Name", 234);
System.out.println("Current Employee Information.
");
System.out.println("Name: " + pr.getName());
System.out.println("ID: " + pr.getID());
System.out.println("Hourly Pay Rate: " + pr.getHourlyPayRate());
[Code] ....
And this is the exception class.
public class InvalidNameException extends Exception
{
/**
No-arg constructor
*/
public InvalidNameException()
{
super("Invalid name");
}
}
PayrollDemo.java:43: error: cannot find symbol
InvalidNameException.InvalidNameException();
^
symbol: method InvalidNameException()
location: class InvalidNameException
1 error
It's just meant to tell the user that they entered an invalid value, which would mean if they entered an empty string instead of a name.
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Feb 14, 2015
I'm doing an aggregation exercise that's suppose to find the volume and surface area of a cylinder. What I'm trying to do is pass values from one class, to a second class, and that second class passes values to a third class.
This may be a clearer explanation: The first class is the main program which sends values to the second and third class. The second class is used do calculations for a circle (a pre-existing class from another assignment). The third class grabs the values that the second class calculated and calculates those values with the one that was passed from the first class to the third class. The first class then prints the outcome.
Problem is when the program gets to the third class, it just calculates the value from the first class with the default constructor from the second class. It's like the second class never received the values from the first class. I think I'm missing a step, but I don't what it is.
First Class:
package circle;
import java.util.Scanner;
public class CylinderInput
{
static Scanner in = new Scanner(System.in);
public static void main(String[] args)
{
//user defined variable
[Code]...
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Dec 26, 2014
Why do we get such output or which line of code produces the output?
1class Egg2 {
2 protected class Yolk {
3 public Yolk() { print("Egg2.Yolk()"); }
4 public void f() { print("Egg2.Yolk.f()");}
5 }
6 private Yolk y = new Yolk();
[Code] ....
/* Output:
1.)Egg2.Yolk()
2.)New Egg2()
3.)Egg2.Yolk()
4.)BigEgg2.Yolk()
5.)BigEgg2.Yolk.f()
*///:~
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Oct 18, 2014
I'm quite new to Java. I have some trouble with understanding how to get two classes to get objects from each other (if that is the correct term).
Lets say I have a login class, in which I have a method checking what the user has entered into the console (I have not displayed the whole code, but this class works as it should and give the user an option to enter username and password and return it true if entered correct).
public static boolean validateUserPass(String userName, String password) {
String[] user = {"admin"};
String[] passwords = {"firkanten"};
boolean check = false;
for (int i = 0; i < user.length; i++) {
if (userName.equals(user[i])) {
if (password.equals(passwords[i])) {
check = true;
Now, in another class I want a display box to appear on the screen and give the user three options: Click yes, no or cancel. I get this to run perfectly alone, this is not the hard part for me. I want the display box only to appear when the correct username and password is given, but I can't seem to figure out how to do this probably.
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Feb 7, 2014
Regarding the code examples in Head First Java, this is from Chapter 5, regarding the beginning creation of the dot com game. There are two classes in quesiton
the first is the SimpleDotComTester class:
public class SimpleDotComTester {
public static void main(String[] args)
{
SimpleDotCom dot = new SimpleDotCom();
int[] locations = {2, 3, 4};
dot.setLocationCells(locations);
String userGuess = "2";
String result = dot.checkYourself(userGuess);
}
}
and the second one is the code for the checkYourself () method in the SimpleDotCom class
public class SimpleDotCom {
int[] locationCells;
int numOfHits = 0;
public void setLocationCells(int[] locs)
[code]....
Now I noticed that both classes use a variable called result; the program runs fine, but assume from the example that you can use the same variable name two different classes;
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Mar 29, 2014
design a class to conduct a survey of three hospitals. you want to know how many sectors (eg operation, children, gastronomic) each hospitals have, and how many doctors there are in each sector.
what is the process of class design?
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Jan 5, 2014
I have a Date class and Time class. Is it possible to pass Time object inside Date constructor so that toString function gives output as 12/05/2013 06:31:30 ?
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Apr 24, 2014
I have two classes.
First and Second.
In First class I want to use methods from Second class. So:
Java Code:
Second s = new Second();
s.secondMethod(); mh_sh_highlight_all('java');
Second thing I want to do is use JTextArea from First class in Second class.
So since it gives me error, I extended First class with Second:
Java Code: public class Second extends First { mh_sh_highlight_all('java');
It look like it should work, no errors etc. Also both things are working separately. But since I used both at once...
Java Code:
Exception in thread "AWT-EventQueue-0" java.lang.StackOverflowError
at package.Second.<init>(Second.java:7)
at package.First.<init>(First.java:17) mh_sh_highlight_all('java');
I can move what I need to First class, and it will work fine, but I want to make this in two classes. But I really don't understand extends, I just use them if there is need for them. So I don't know how to handle this problem.
I also tried to extends Second just like First:
Java Code: public class Second extends JPanel implements ActionListener { mh_sh_highlight_all('java');
Instead of extending First, but it can not be done, since ActionListener is in First...
Well. Also addActionListener can maybe solve my problem?
I'm using:
Java Code: xx.addActionListener(this); mh_sh_highlight_all('java');
Maybe I can use something instead of this? But what?
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Jan 19, 2015
Wondering, what is exactly reason for existence of inner classes? Are there problems that without them you can not resolve?
Anything beside emulate multiple inheritance - when your class need to extends the real classes, and not implement multiple interfaces ?
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Mar 28, 2015
I have a folder of classes that I am packaging together. Some classes are being packaged and compiling just fine. My other classes in the same package, however, are saying that they cannot find these classes.
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Apr 12, 2015
What i'm trying to do is to pass a bufferedreader string from main method to a class that will set on how fast or slow a message will be displayed but it has to be displayed on a JTextArea that's in a constructor class.
import java.awt.*;
import javax.swing.*;
public class demo {
JFrame frame = new JFrame ("Idle Game Test!");
JPanel backGroundPanel = new JPanel ();
JPanel statusPanel = new JPanel ();
JPanel buttonPanel = new JPanel ();
JPanel bigPanel = new JPanel ();
JTextArea message = new JTextArea ();
[code].....
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Aug 7, 2014
So I prefer to use Emacs rather than using Eclipse or some other IDE and I am wondering how to include external classes in my main file?
For instance I have my main file (the one that includes my 'main()' function) and then I have another class (seperate file(s)) for creating a GUI, or making a game and using a Player class, Weapon class, etc. How can this be done? Do I just use 'extends myclass'?
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Jan 21, 2014
I would like to use the attribute A of my class Selecter1, in my main class Resizing. How?
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