Passing Values To Two Classes And Retrieving Values From Those Classes
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
I have a very standard Lab assignment. It's probably been seen a lot. I wrote the first part not realizing I had to write a second class to do use the methods. I'm not sure how to change my program to call methods from my second class instead of doing all my calculations with user input in my first class.
Here's the first class' code:
package tickets; //Imports classes used for "Ticket" application. import java.util.*; import java.text.DecimalFormat; public class Tickets {
[Code] ......
The code is obviously incomplete. I have not tried to compile, nor would I expect it to compile right. I'm not sure how to move my calculations from the first class shown above into my second class and use them as methods.
I currently building a hotel reservation system, and I'm having issues with retrieving and setting other values from a JTextField.
What I'm trying to do is to retrieve the value that was inputted into a textfield, and then setting that value to a string in another class.
In here, I'm trying to retrieve values from the JTextField:
@Override public void actionPerformed(ActionEvent event) { GuestInfo gi = new GuestInfo(); if (event.getSource()==roomView) { roomViewFrame.setVisible(true); roomViewFrame.setSize(1000, 600);
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();
Basically I am making a paddleball game, like i'm sure everyone does in learning Java. I'm supposed to use different classes for each component, i.e. one for the ball, one for the paddle, and one for the display, then finally one as a 'controller' to implement mouselistener and stuff.
However, I can't quite grasp how to implement the paintComponent method. I know I can only have it in one class extended from JPanel, and I have the syntax for creating an object which I understand is something like this:
public void paintComponent(Graphics g){ //this is the rectangle my game will be played on, super.paintComponent(g); //a gray background to define boundaries for the ball g.setColor(Color.GRAY); g.drawRect(0, 0, Frame.getHeight(), Frame.getWidth());
However what I don't understand is, how do I then pass this graphics object to the ball and paddle to let them draw themselves? I found something that described it like this here
What I don't get is, if I use this, where would I put the drawRect and stuff to make the other shapes I need? in their class, under the entity.Draw(g) method? or in the display class where it calls the graphic object in the first place?
Last, how can I have my controller class refresh the displays of each of these with the timer I have implemented? Is there a simple way to call one refresh command and have it refresh the drawing of both the paddle and ball simultaneously, or would I need to call a separate refresh command for each object?
I have a properties file with a set of commands and their meanings (Command = the meaning). I Populated a jtree with the keys from the properties file, now when I click a node in the jtree (key) I want the value of that selected key to go in the panel that sits in my app next to the jtree.
I am trying to pass the values for UPPER_BOUND and LOWER_BOUND from the main method into the getValidNumber method. However, I'm not sure how to do this. The rest of the code is correct as far as I know, I just need to get the values for the bounds into the getValidNumber method. How would I do this? the notes in the main method explain what I need to do.
public static void main(String[] args) throws FileNotFoundException { Scanner kb = new Scanner (System.in); final double LOWER_BOUND = 0; final double UPPER_BOUND = 100; //Call the getValidNumber method, passing it the values LOWER_BOUND and UPPER_BOUND. //Take the returned value and store it in a variable called num. //Print out the value of num (here in the main method)
I am trying to get the username and password for one class and send them to another. However I cannot send them in the constructor because a database class is getting them and I need that constructor blank. However if I do not pass the class in the constructor I get a NULL error, even better when I do pass it in I seem to get a thread lock. I do try to do my own housekeeping and close the one frame before I open a new one but it doesn't work. I will do my best to show the design of the program.
program starts Java Code: public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { // connects to database and generates a GUI new UserPromptScreen();
[code]....
I have to pass in UserPromptScreen in for it to work. This will cause me issues later with my design.
I'm supposed to write a program that reads in 20 numbers stores them into a one dimensional array and then create a method that will calculate the average of the numbers in a separate method.
I've written a for loop in the main method that will take in the numbers but now I need to know how I can pass those values to a method that will calculate the average.
public class ConstructorHomework { private static double average; //Declaring the Global Variable //This Method Calculates The Average public void avg(int x){ average = x/20;
[Code] .....
This is the main method an it contains the for loop that will take in 20 numbers
public static void main(String[] args) { Scanner input = new Scanner(System.in); final int size = 20; double[] array = new double[size]; for (int i = 0; i < array.length; i++){ array[i] = input.nextDouble(); } //
Here I was trying to create and object and use it to pass value to the method
ConstructorHomework a = new ConstructorHomework(); a.avg(); //Problem is that I don't know what to put in the brackets a.showNum(); } }
How to pass the value of a field in a database from one view to another. I currently have a list of members drawn from a database.
The members view is a list of members. From the list the user clicks view button to view a particular member. This is achieved by using a inputHidden tag with the value of the list of members in a data table.
in the RequestScoped bean I am able to use FacesContext to extract the value of idToken from the requestParameters and create the view for the particular member.
One field in the member view I would like to toggle - "Y" to "N" or vice versa via a commandButton. The issue is I can find no way of passing this single value back to the bean as is.
<td>Active:</td> <td><h:outputText value="#{controllerBean.member.active}" /></td> <td> <h:outputLabel value="To change toggle active button below" /> <h:inputHidden id="actToken" value="#{controllerBean.active}"/> </td> //further down the view <h:commandButton style="float: right" value="Toggle Active" action="#{controllerBean.toggleActive()}"/>
The issue is the value is displayed within the output text - how to pass the value into the inputHidden value.
combo is the private CombinationLocker object I created within the Locker class. Do I need to pass the combo object on to the CombinationLock class? For reason, I do not comprehend, the combination password from the main class is not passing through to the CombinationLock class, and the combination values are all zero.
Long story short: The program takes user values (temperature) and converts them to the opposite (C >> F / F >> C)
I originally started this program with three separate arrays but then decided that it would be a good opportunity to use a two-dimensional array and one other.
The two-dimensional array has 2 rows, 10 columns. The second is a normal String array ...
Java Code:
String[][] myTemperatures = new String[2][9]; String inputAssembly[] = new String[9]; mh_sh_highlight_all('java');
I prompt the user for to enter temperature values, using a GUI and jbutton to distinguish F/C. Each time the user clicks 'continue', the values are stored into the two-dimensional array. One row holds the temperature, the other holds the C or F designation.
Java Code:
// CONTINUE BUTTON CLICK ACTIONS class ContinueButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent arg0) { // TODO Auto-generated method stub input = view.getTempValue();
[Code] ....
This is where I am experiencing the trouble and I cannot seem to get the Debug to work properly here. When the two-dimensional array is full OR the user clicks 'calculate' instead of 'continue', the Calculate event is performed via an ActionListener.
Java Code:
// CALCULATE BUTTON CLICK ACTIONS class CalculateButtonListener implements ActionListener{ @Override public void actionPerformed(ActionEvent arg0) { // TODO Auto-generated method stub String hold; Double temp;
And I get a ton of errrors ...
Java Code:
Exception in thread "AWT-EventQueue-0" java.lang.NumberFormatException: For input string: "[Ljava.lang.String;@7441b1fd" at java.lang.NumberFormatException.forInputString(Unknown Source) at java.lang.Integer.parseInt(Unknown Source) at java.lang.Integer.parseInt(Unknown Source)
[Code] ....
I imagine the issue lies within how I am handling the two-dimensional array in the CALCULATE event and/or converting the String[][] to String then parsing to an Integer.
Would this be better done is separate arrays (not using one two-dimensional, but storing 34C, 45F ... in one. I think this would be difficult for me to parse for conversions).
I just kinda get stuck when it comes to passing values into constructors, using main method or static method functionality. In theory i kind of understand how it work but when i type it, it's totally different! I have to have a junit test too but i guess i could do that in the end.
I have attached the assignment. So, how to proceed with this:
public class Flight { int flight_number, capacity, number_of_seats_left; String origin, destination; String departure_time; double original_price;
I need a way to store the pixels values currently on the screen and compare them to the values on the first frame. Right now I'm using glreadpixels as follows:
currentBuffer= BufferTools.reserveByteData(mapSize); glReadPixels(mapStartX, mapStartY, mapWidth, mapHeight, GL_BLUE, GL_UNSIGNED_BYTE, currentBuffer); for (int i = 0; i < mapSize; i++) { if (currentBuffer.get(i) != baseBuffer.get(i)) { //Do nothing continue; } //Do something }
This works perfectly fine but turns out to be a real bottleneck, dropping the fps to a third of what it was. Is there any quicker way? All I'm after is speed, I don't even need to show it on the screen if the comparison is made "behind the scene".
I have a question in mind that this is my registration form. I am sending these values from HTML form to server and database. I have question that in my case if I click next to Add Another Mobile no in HTML.then a block is genereated and each time a new name is generated.
My Question is if I click 6 times then 6 name attribute are generated. How can I send and differentiate them on my server side.
Because at their I will use something request.getAttribute("Attr_Name");
I have a JScrollPane with two coulmns. In the first column I have an image pane JTable, and in the second a list with names of sections. This second column I try to divide in two columns, one (the second column) to display the names of the sections (each row contains one name), and in the other column (the third) I want to show some values for every section in the row respectively. But, instead of displaying the desired values in the third column, I get the same names of the sections as in the second column.
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.
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;
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.
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 ?
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?
