New Instance Variable Values Not Updating
May 6, 2015
Alright, I have a JavaFX gui that is creating a new instance of data calculation to graph in a chart; however, the data is not updating each time the Platform.runLater() feature executes. Each time an event occurs, a new instance with the same variable name occurs. I use to get methods to retrieve the data I want, so shouldn't the values update each time the new instance is created? This is a very condensed version of what happens with the event, but this is what is not working correctly.
Event:
solarPlot = new SolarTracker();
solarPlot.getElevation();
solarPlot.getAzimuth();
Class constructor :
public SolarTracker() {
[Code] .....
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Feb 5, 2015
Let's pretend I'm working on an RPG. Like in all RPGs, there are items found all throughout the imaginary world. Each player and NPC can obtain an item. My question will concern those items.
In other words, I'd like to use instances of a class in multiple places of the code. Each instance will have its own, individual values of instance variables, with one obvious exception: itemQuantity should have a different value in playerInventory, npcInventory, etc. Also, I'd like a list of all items that can be found in the game. This list doesn't need itemQuantity at all.
class Items {
String itemName;
float itemWeight;
int itemQuantity;
[Code] ....
The question is: should I really make itemQuantity an instance variable of the Item class? It seems as though for each copy of the Item class I should create a separate copy with different value of itemQuantity, but that's not very efficient. Where is the error in my logic?
What's important is that there may be plenty items in a game and a player may be given power to create new items during the course of the game.
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Aug 20, 2014
I am trying to create a tree that is like a take on 21 Questions. The tree pretty much just starts with three default values: the root/first question "Is it a mammal?", a left child "is it: human?", and a right child "is it: fish?", and then it builds off from there. It goes left for YES and right for NO. If the program guesses the wrong animal the user must enter the correct answer and a question that will distinguish the correct answer and the failed answer. That new question then becomes both the the failed answer and new answers's parent.
A little visual:
....................Is it a mammal?
...........It is: human?........Is it: fish?
*lets say it is a mammal but not human, ie a dog
Updated tree:
.....................Is it a mammal?
.....Does it have a tail?............Is it: fish?
Is it: dog?......Is it: human?
My problem is that after I update the tree 3rd time the values do not change properly. Lets say it is a mammal and its does have a tail, BUT its a cat, then, the updated question, which would now go before "is it: dog?" would be something like: "does it chase rodents?", which its left child would be cat and right would be dog.
However, when my program displays the values it would go something like this:
//first run: GOOD
Think of an animal and I will guess it!
Is it a mammal? Enter yes or no:
yes
Is it: human?
no
[Code] .....
So pretty much I can't understand what I'm doing wrong since the values in the print statements are right, but they are wrong during the actual run. Where is my error?
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May 4, 2014
Write a subclass of BasicGame in which the computer asks the user to choose a whole number from 1 to 100, inclusive. The program then makes a number of guesses. After each guess, the user tells whether the guess is too high, too low, or exactly right. Once the computer "knows" what the correct number is, the computer tells the user the correct number and the number of guesses tried. Have the program ask the user after each game whether she wants to play again. Design the program so that it always guesses the correct answer by the seventh try at latest. Hint: Have two instance variables that keep track of the smallest and largest values that the guess could be (initially 1 and 100). After each wrong guess, update these smallest and largest values appropriately.This is what I have written for the assignment:
Java Code:
import javax.swing.JOptionPane;
public class GuessThatNumber extends BasicGame
{
private java.util.Random randy;
private int itsCompNumber;
private int itsHigh = 99;
private int itsLow = 1;
[code]...
The part I'm having trouble with is changing the high and low values based on the input of "too high" or "too low," which I tried in the continueGame method... When I test the game, the values for itsCompNumber aren't restricted by the user's input at all, and I'm not sure how to fix it.
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Feb 23, 2015
I am working on a project and it asks me to "Provide appropriate names and data types for each of the instance variables. Maintain two GVdie objects" under class fields. I am unsure as to what is being asked when asking for two objects as instance variables and how I would write that...
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May 5, 2014
I'm just wondering why variables in interface can't be instance scope?
interface Test{
int a;
}
And then
Test test = new TestImpl();
test.a=13;
Yes, it violates OO, but I don't see why this is not possible? Since interface is not an implementation, therefore it can;t have any instance scope variable. I can't find the correlation of interface being abstract and being able to hold instance scope variable. There's gotta be another reason. I'm just curious about any programmatic limitation, not deliberate design constraint. the example of programmatic limitation is like when Java forbids multiple inheritance since when different parents have the exact same method, then the child will have trouble determining which method to run at runtime.
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May 23, 2014
Is there anything wrong on my code?
import java.util.*;
public class Card
{
private String description;
private String suit;
private int value;
private static final String [] cardName {"Ace","Two","Three","Four","Five","Six","Seven","Eight","Nine","Ten",
"Jace","Queen","King","Joker"};
[Code]...
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Mar 25, 2014
I'm having trouble to fully understand the difference between instance and class variables.
I though it was all about the static, i.e:
int age; // instance variable
static int age; // class variable
What's behind this?
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Jul 10, 2014
Implementation that proves that instance variables are not thread safe ....
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Oct 24, 2014
Whenever I run this I get:
There are not enough funds to do that
Balance: $0.0
Monthly Interest Rate: 0.375%
Account Start Date: Fri Oct 24 08:03:40 EDT 2014
I assumed that this is because the constructor Account(); is setting the variables to 0 every time the program runs even though I'm passing other variables through to methods and constructors. I've looked up similar programs and this is how it's done though. The steps to my homework say to create a no-arg constructor Account() that creates a default(0) account Id and balance. What did I do wrong?
import java.util.Date;
public class Account {
private int Id;
private double balance;
private double annualInterestRate;
private Date dateCreated = new Date();
public static void main (String [] args){
//Objects of Account to get non-static methods
[code]....
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Apr 25, 2014
Can I assign multiple values to one variable? For example I want myNum = 0 thru 9 you see im trying to program a password checker program to verify that the password meets all the criteria 8 char long, 1 upper case, 1 lower case, 1 numeric, 1 special, and don't contain and or end
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Oct 2, 2014
Java Code:
public class Puppy{
int puppyAge;
public Puppy(String name){
// This constructor has one parameter, name.
System.out.println("Passed Name is :" + name );
}
public void setAge( int age ){
puppyAge = age;
[Code] ....
How do I put 3 values of the each variable without replacing the last inputted one?
Like when I input "Tommy" and input another name "Gerald", "Tommy" won't be replaced by "Gerald" when I input again.
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Mar 7, 2014
I've Parent and child(extends Parent) class To initialize the constructors, I'm injecting from google.juice#injector. Let me show the code,
Parent.class
public class Parent{
private Animal animal;
@inject
Parent(Animal animal){
this.animal = animal;
[code].....
When I do this, ClassCastException is happening. Why is it so? Is there any way to convert instance of parent to child instance.
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May 21, 2014
Given the case I have an object which is assigned only once. What is the difference in doing:
public class MyClass {
private MyObj obj = new MyObj("Hello world");
private MyClass(){}
//...
}
and
public class MyClass {
private MyObj obj;
private MyClass(){
obj = new MyObj("Hello world");
}
//...
}
Is there a difference in performance or usability? (Given also the case there are no static calls expected) ....
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Oct 27, 2014
The term "Local variable" is related to scope. That is a local variable is one which is defined in a certain block of code, and its scope is confined inside that block of code.And a "Member variable" is simple an instance variable.
I read in a discussion forum that when local variables are declared (example code below), their name reservation takes place in memory but they are not automatically initialized to anything. On the other hand, when member variables are declared, they are automatically initialized to null by default.
Java Code: public void myFunction () {
int [] myInt; // A local, member variable (because "static" keyword is not there) declared
} mh_sh_highlight_all('java');
So it seems that they are comparing local variables and member variables. While I think a member variable can also be be local in a block of code, isn't it?
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Apr 29, 2014
I am using JSF2 with Primefaces. Here is my business requirement-Hidden field on JSF page should take the value from the session object that is set in managed bean. Session object is updated every time when the user submits the page. I am able to update the session object in the managed bean and able to get the value in the hidden field first time and after that i see the same value in the hidden field even though session object has different value. Here is the hidden field: <h:inputHidden id="xyz" value="xyz"/> i tried using sessionScope but still didn't work.
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Feb 20, 2015
I have a jTextPane set up and a panel with radioButtons. My jTextPane displays the contents of a text file I have chosen. The 3rd line, 4th index, displayed in my jTextPane specifies a value of type int. When I click my radioButton, I would like that value to increase by 1. So far, I have the following code. I tried to pane.setText(value + 1), but that doesn't seem to work. How do I update the value and display the updated value in jTextPane?
My code :
private final ActionListener actionListen = new ActionListener() {
for(String line: pane.getText().split("")){ String lineThree = line[3];
int value = lineThree.charAt(4); if(radioButton.isSelected()){
pane.setText(value+1); } }};
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Mar 20, 2015
The program runs well , it adds the applet but it dosn't update the interface unless I press "_"(Minimize) . To be more clear , the object paints a spring wich goes through 4 stages , it is added to the JFrame but it dosn't uptade until I minimize the frame , that is when it goes to the next stage .
The main class which calls the spring to be added to the frame :
public class principal implements ActionListener ,Runnable{
JTextField field;
JFrame frame;
private class Action implements ActionListener {
public void actionPerformed(ActionEvent event) {
frame.repaint();
[Code] .....
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Oct 18, 2014
import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
[Code]....
I am trying to Make A GUI which has a Jcombo box i also want it to have a jlabel that up dates depending on which option the user selects from the JcomboBox
for exampl if i select lion i want it to say you chose lion on the Jlabel and if i choose ostrich i want it to say ostrich and so on
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Sep 26, 2014
I have two images. I want to be able to click them and kick off a call to a listener in Java to change a value in the bean. I also want the view to update my dropdown (labeled "menuModel") to either be rendered or not, depending on which image I click. Alternatively, I would be fine with the dropdown simply being disabled and enabled for the same criteria.
So far, the listener kicks off fine, and the value gets updated correctly in the bean. However, the view never gets updated. I have tried this a hundred different ways, but nothing seems to work. If I hit refresh on my browser, the view updates. But I want it to do it automatically.
I am using standard JSF 2.1.
<div style="font-family: Verdana; font-size: 10pt; color: #FFFFFF">
<h2>Calibrations</h2>
<h:form id="tunerSelectionForm" style="color: #000000">
<h:commandLink>
[Code] .....
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Jun 15, 2014
I have loaded the combo box at starting of program.When i am adding the element to combo box through database it's not updating visually.But the inserted data is successfully loaded in List.
void update_Attan() {
DefaultComboBoxModel nm = new DefaultComboBoxModel(new StudentMethods().update_combo_AttendanceType());
cmbStdAttType.setModel(nm);
}
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Sep 25, 2014
When I add an element to my array, I have to make sure that it stays a heap, ie every child is smaller than its parent. However the method that I am using for this, trickling up, is not updating the elements properly, it pretty much just leaves is as is.
Here is the relevant code:
public class MaxIntHeap {
int[] array;
int actualSize = 0;
public MaxIntHeap(){
array = new int[20];
[code].....
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Aug 14, 2014
Why the Progress Bar is not Working in Second attempt?When i am Invoking Below Method on actionPerformed at first attempt its Working Fine but After that Its Not Working at all....
void initWait() {
go.setEnabled(false);
browse.setEnabled(false);
choice.setEnabled(false);
wait.setVisible(true);
wait.setMinimum(0);
wait.setMaximum(Info.getMp3().length);
System.out.println(Info.getMp3().length);
wait.setStringPainted(true);
[code]...
for a better Understand see this Mp3Arranger.jar or see the Whole Project SourceCode
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Oct 22, 2014
My program is working fine. When I executes it, it shows me this:
The clock is 54 minutes over 23 (+41 seconds.
and when i press ENTER, it shows me this:
23:54:41
But then it won't show me the update. I want to update the time, for example when I started the execution the time was 23:54:41 but it must show me something like 23:54:45, because I need the current time.
I have searched the whole internet about this but I don't know how to use the "Date.update ();".
Here is my code
package p2;
import java.util.Calendar;
import java.util.Date;
import javax.swing.JOptionPane;
public class Time {
public void myTime() {
Calendar cal = Calendar.getInstance();
[Code] ....
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Jan 11, 2015
Given a reference variable : Car c1 = new Car();
when we create another variable and set it equal to the first : Car c2 = c1;
we're pointing c2 at the same car object that c1 points to (as opposed to pointing c2 at c1, which in turn points at the car). So if we have code like,
Car c1 = new Car();
Car[] cA = {c1, c1, c1, c1};
are we doing the same? Are we creating four *new* reference variables, each of which points at the same car (again as opposed to pointing them at c1 itself)? I think so, but want to make sure I'm understanding this correctly.
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Feb 18, 2015
I have an application scoped and i want to edit it from request scoped data. I use this code but application scoped data are not updating. What i am doing wrong?
Application Scoped Data
@ManagedBean
@ApplicationScoped
public class ApplicationData {
protected String contactEmail;
public String getContactEmail() {
return contactEmail;
[Code] ....
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