ArrayList Through Multiple Classes?
Oct 25, 2014
I have to make a retail item class that has description, price and quantity. I then have to make a CashRegister class that calculates subtotal, tax, total and displays it (toString). I also have to make a driver class to call the methods from main. I have no clue what I am doing and what I have done does not work. I am trying to make it sort of like a cart, in the CashRegister it should ask the user to enter the description, quantity purchased and the price. Then it would send that to the arraylist of retailitem. I am having trouble using those items in my other methods and then do not know how to call those in the driver class.. So here are my classes:
public class RetailItem {
private String description;
private int quantity;
private double price;
public RetailItem(){
description = "";
quantity = 0;
[Code] ....
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Oct 25, 2014
Alright.. So I have to make a retail item class that has description, price and quantity. I then have to make a CashRegister class that calculates subtotal, tax, total and displays it (toString). I also have to make a driver class to call the methods from main. I have no clue what I am doing and what I have done does not work. I am trying to make it sort of like a cart, in the CashRegister it should ask the user to enter the description, quantity purchased and the price. Then it would send that to the arraylist of retailitem. I am having trouble using those items in my other methods and then do not know how to call those in the driver class...
So here are my classes: [URL] ....
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May 5, 2015
I'm very new to Java, and I am creating a program that takes multiple user input to create one face. I have a class for the eyes, nose, lips, and headshape. For some reason, my program is not drawing the graphics. ***for question purposes, I have only included my head shape class and my test class****
my "test" class:
import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
public class FaceTest
{
public static void main(String[] args)
{
String head = JOptionPane.showInputDialog("Would you like a circle, square, rectangle shaped head?: ");
[Code] ....
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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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Mar 1, 2015
I have recently start learning about objects and classes in java. I understand that in order to use multiple classes in one file you need one class to be public and the rest are private. But after that I don't understand how to invoke the private class in the public class. I thought if I tried programming on my own I can have a better understanding of it, but had no success.
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Jan 31, 2015
I'm having problems with this I've code like:
Java Code:
Public Class{
Objects
Constructor(){}
ActionListener Method(){}
Main Function()}
[Code]....
but I cannot declare variables in this method, how can I do this what can be the simplest method?
In addition: I've a marksheet class, a calculator class, & in main class I've 2 buttons one for marksheet & one for calculator, how can I make it so that if user clicks on marksheet button that class should be called & so?
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Mar 6, 2014
I have multiple Java classes that holds lots of time based parameters, e.g.: (simplified):
Java Code: class Engine {
float rpm;
boolean enabled;
int runningTime;
[code]....
Is there any simply solution to map all these parameters from my TimeRecord to one list(vector,map) of params that user can choose from and see the value in proper form (floating type, boolean type) ?
I just want that user can pick a paremter's name from list or combobox and choose parameter that he wants to see. I don't want to duplicate the data - just some kind of mapping algorithm between list of parameters names and my TimeRecord. eg. some collection class that holds all names and connections: Parameters params; fill combo/list from this class for ( String name : params ) { combo.add(name);}, then when user picks some field from combo: params.getValue( myTimeRecord, name ) return correct parameter value (just my first thought)
Later, I want to replace all floats,ints,booleans with some kind of templated class eg. Value which will hold all kinds of measurement unit with conversion support - but it's only a plan now.
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Nov 1, 2014
I was reading the book, "Head First Java" and it was talking about how there may be multiple classes in a large application, but there will be only one main method.how does it work that way? How can you have multiple classes, but only one main method?
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Jan 16, 2015
I have multiple classes in one package and was wondering how to I use one class while in another?
What I mean is I have one sheet with a class and another sheet with another class. (Separate tabs in Eclipse).
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Sep 12, 2014
I'm trying to create a Java swing chess application, but would like to divide the GUI part of it into at least two different classes (possibly more later, but I'm not sure yet). Currently I have a mainGUI class and a ChessBoard class, both of which extend JFrame. I want the main GUI class to contain a JPanel which will house several components, including a JPanel originating from the chessboard class that contains the actual board.
Is there any way to do this? I tried just creating a ChessBoard object in my main GUI class and then adding it to the component, but I got an illegal argument exception, because apparently you can't add one JFrame to another. How to do what I'm trying to do, or just how to split GUIs into multiple classes in general?
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Nov 29, 2014
If I lets say have an interface Animal, and I create a lot of classes with a different animal name that implement the interface Animal. Then I create an ArrayList of Animal. Then I would put in lets say Dog class into the ArrayList, which has custom methods and data that the Animal Interface doesn't have, is this data ripped away except for the methods that are put in the Animal interface? So if I would cast the Animal back to Dog, would it retain all the data that existed before it was placed in the ArrayList?
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Aug 16, 2014
I studied that java does not support multiple inheritance using classes. It is fine practically, but I have still a question in mind:Lets see the below code.
class Test{
------
------
}
class MyTest extends Test{
---------
---------
}
Here, as we know that that Object is Super class for every class in java. and I have already extends a Test class in MyTest.My question is: How is it possible to extend features of two class at the same time?
Theoretically,
MyTest extends Object &
MyTest extends Test.
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Feb 10, 2014
For example, if I have a class called Teacher with the constructor:
public Teacher(double yearsTeaching, boolean isMale, double age)
{
this.yearsTeaching = yearsTeaching;
this.isMale = isMale;
this.age = age;
}
How would I add it to these parameters to my ArrayList in my Tester class?
List<Teacher> teachers = new ArrayList<Teacher>();
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Dec 27, 2014
I have an ArrayList of tens of thousands of elements, and want to remove the items at a given set of sorted indices like {1,5,29,318,499,583}. It seems like this operation could be performed in linear time and space by first finding a cumulative sum of the shifts needed to move everything to their right positions and then shifting every item. On the other hand, removing and shifting one by one would seem to require many more shifts. Is there a way to do this in Java's ArrayList?
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Nov 16, 2014
I have declared an array list that will store data type of 1 Character and 2 integer. The data that will be store in this list is
1. A = {0 3}
2. B = {0 5}
3. C = {0 3}
4. D = {0 3}
5. E = {0 5}
6. F = {0 6}
Now here the alphabets are routers and integers are there con1 and con2 respectively. I have a set of router={ A,B,C,D,E,F}.
Step 1:I have to subtract con1 from con2 i.e. (3-0) of all the routers and
Step 2: then put the router having largest value in new set 1 and
Step 3: then this router will be subtract from the router set.
Step 4:then again I have to repeat the step 1 until the value of routers become <= 1.
Now what I did is I defined 3 arrays first is String array that stores names of routers, 2nd array that stores the first value and 3rd array that stores the second value. I can find the largest value but how to store the name of router against the largest value in the set.
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Jan 24, 2014
I just started playing around with Java for awhile, but got caught up in a problem when using ArrayList.
CinemaAppMain
public class CinemaAppMain {
public static void main(String[] args) {
new CinemaApp().start();
[Code]....
I am trying to get the movie name and theatre title from their ArrayList, and I know I need to go through the movie list & theatre list to find their name & title, and compare it with the user input and print out the result.
I use for(int i=0;i<movies.size();i++) to go through the the movie list, and I tried using for(int i=0;i<theatres.size();i++) to go through the theatre list. But when I printing multiple time with different user input value, it will show me strange result (screening have same movie name & theatre name, the else if statement is printed below the user input, user input is printed more than once after the first time).
Edit: I know its wrong for me to use nested for loop,if not, another solution is needed to get the item inside both of the list. (getting the "title" from movie list & "name" from theatre list)
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Oct 25, 2014
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
set("", "");
method, it only sets the last one that is called.
Example:
set("section1", "section1Item");
set("section2", "section2Item");
set("section3", "section3Item");
Only section3 would get set, and not the others.
Otherwise, if the file contained a section already, then each section (section1, section2, section3) would get set.
Here's how I set the data to the file:
public static void set(String section, String data) {
files.openFileWriter();
files.file.delete();
reCreateFile();
String beforeItem = section + ":" + files.dataList.get(section);
if(files.hasReadData) {
[Code] ....
And here is how a retrieve the data and set them to my arraylist/hashmap:
public void getData() {
String line = null;
openFileReader();
StringBuffer sb = new StringBuffer();
[Code] ....
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Jan 13, 2014
I have a code to resize a single rectangle. I would like to display and resize multiple rectangles independently and according to my research on the net, the best way is to use an arraylist. So I modified the code in this sense, except ...when I run the code, the rectangles appear good but impossible to resize. I think the problem comes from mousePressed, Released, Dragged and Moved methods. When I use the mouse to resize the rectangle, nothing happens. The code does not interact with the arraylist, and therefore with rectangles it "contains". Resizing is my main class, the MouseAdapter is in the Resizer class (below).
Resizing component; boolean dragging = false; // Give user some leeway for selections.
final int PROX_DIST = 3; Path2D.Double selectedPath; public Resizer(Resizing rz) {
component = rz; component.addMouseListener(this);
component.addMouseMotionListener(this);
[Code] .....
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Oct 25, 2014
I managed to retrieve data, and set data in my own ways in which I like. But my problem is, if the file does not contain anything (fully empty), when I try to use my
set("", "");
method, it only sets the last one that is called.
Example:
set("section1", "section1Item");
set("section2", "section2Item");
set("section3", "section3Item");
Only section3 would get set, and not the others.
Otherwise, if the file contained a section already, then each section (section1, section2, section3) would get set.
Here's how I set the data to the file:
public static void set(String section, String data) {
files.openFileWriter();
files.file.delete();
reCreateFile();
String beforeItem = section + ":" + files.dataList.get(section);
[code]....
And here is how a retrieve the data and set them to my arraylist/hashmap:
public void getData() {
String line = null;
openFileReader();
StringBuffer sb = new StringBuffer();
[code]....
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Dec 8, 2014
I have i am trying to implement tooltip through javascript, like when we click on an image link tooltip should be displayed and it should have close button/ close image to close that tooltip.like the same way i will have multiple images on page, when ever i click on the images all tooltips should be displayed on the page when ever i want to close that then only it should close through close button on tooltip.can we do it through java script or will go for jquery.
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Feb 28, 2014
I'm trying to create my own arraylist using Collection. My program doesn't do anything. Obviously, I haven't a clue.
import java.util.Collection;
import java.util.Iterator;
public class MyArrayList<T> implements java.util.Collection<T> {
private int size = 4;
private T[] mArray;
public MyArrayList(String[] args) {
[Code] ....
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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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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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Jul 8, 2014
I have stumbled onto a problem with ArrayLists (not sure if nested ArrayList objects would be a more accurate description) ....
As simply put as I can describe it, I have an Inventory class which creates an ArrayList of a Product superclass, which has two subclasses, PerishableProduct and ItemisedProduct.
By default, the program is meant to have a starting inventory, which is why I have added them in the constructor
public class Inventory {
private List<Product> products;
public Inventory() {
addProduct(new Product("Frying pan", 15, 20));
addProduct(new PerishableProduct("Apple", 5.8, 30, 7));
addProduct(new ItemisedProduct("Cereal", 5.8, 0));
// this is where I am having problems. Wanting to add
// objects to the ItemisedProduct's ArrayList for cereal.
}
Within the ItemisedProduct subclass is yet another ArrayList which is meant to hold serial numbers.
public class ItemisedProduct extends Product {
private ArrayList<String> serialNumbers = new ArrayList();
public ItemisedProduct(String name, double price, int qty) {
super(name, price, qty)
[Code] .....
My problem is that I do not know how to populate the serialNumbers ArrayList from the Inventory class' constructor. Because technically, quantity is defined by how many serial numbers are created.
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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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