john-paul York

Rob Spoor wrote:A Thread ends when its run() method ends.

am I correct in thinking the run() method is like the start() method? I was trying to figure out when the start menu finishs to print a message out....but can't seem to get it to work....I tried using a variable and then something like this:

if(horseOne.var != horseTwo.var)
{
print a message
}

but that did not work. My thought was if the two variables started the same and when one thread was done it could change its variable an they would be different. This if statement would then kick in and print the message...but as mentioned..that did not work.

I am creating a racing program to practice simple threads and this is what I have so far:

class RaceHorse extends Thread { private String str; private int num; boolean finished = false; RaceHorse (String s, int n) { str=new String (s); num=n; } public void run ( ) { for (int i=1; i<=num; i++) { System.out.println(str + " "); if(i==num) { finished = true; } } } }


class Race { public static void main(String args[]) { RaceHorse horseOne = new RaceHorse ("Golden Ticket",50); RaceHorse horseTwo = new RaceHorse ("She's a Winner",50); horseOne.start ( ); horseTwo.start ( ); } }

So this is simple enough, it prints out the name of the horse 50 times each randomly as the threads run at the same time. I am now looking to have a message printed out to say which horse won, this is where I run into issues. Is there a way maybe when a thread stops to print a message out? Can someone point me in the right direction?

I am creating a simple tic tac toe game and when I try to add a JButton array to the applet it displays nothing, so I have for now went to displaying the buttons one at a time. My code as it stands now is as follows:

import java.awt.event.*; import javax.swing.*; import java.awt.*; public class JTicTacToe extends JApplet implements ActionListener { JLabel messagesLabel=new JLabel("Tic Tac Toe - X goes first"); JPanel gamePanel=new JPanel(new GridLayout(3,3)); int count=0; JButton b1=new JButton("1"); JButton b2=new JButton("2"); JButton b3=new JButton("3"); JButton b4=new JButton("4"); JButton b5=new JButton("5"); JButton b6=new JButton("6"); JButton b7=new JButton("7"); JButton b8=new JButton("8"); JButton b9=new JButton("9"); public void init(){ getContentPane().setLayout(new BorderLayout()); getContentPane().add(messagesLabel, BorderLayout.NORTH); add(gamePanel, BorderLayout.CENTER); b1.addActionListener(this); gamePanel.add(b1); b2.addActionListener(this); gamePanel.add(b2); b3.addActionListener(this); gamePanel.add(b3); b4.addActionListener(this); gamePanel.add(b4); b5.addActionListener(this); gamePanel.add(b5); b6.addActionListener(this); gamePanel.add(b6); b7.addActionListener(this); gamePanel.add(b7); b8.addActionListener(this); gamePanel.add(b8); b9.addActionListener(this); gamePanel.add(b9); getContentPane().add(gamePanel, BorderLayout.CENTER); } public void actionPerformed(ActionEvent e) { String actionCommand=e.getActionCommand(); if(actionCommand=="1"){ if(count==0){ b1.setText("X"); b1.setEnabled(false); }else{ b1.setText("O"); count++; } } } public static void main(String[] args) { JTicTacToe game = new JTicTacToe(); } }

the code I tried to use to add a JButton array was like this(I used something like this for checkboxes in another program):

JButton[] buttons = new JButton[9]; //placed where the buttons are now for (int i = 0; i < buttons.length; i++) //placed in the init() { buttons[i] = new JButton(String.valueOf(i + 1)); buttons[i].addActionListener(this); //adding listeners to checkboxes } for (JButton buttons1: buttons) // placed in the init() { gamePanel.add(buttons1); }

using the above my applet comes up blank..doing it the way at the top..it shows fine.

bah...I think I have it...JPanel....if I research JPanel this should put be in the right direction I am thinking?

I am doing a program that is suppose to do the following:

Create a JFrame that uses BorderLayout. Place a JButton in the center region. Each time the user clicks the JButton, change the background colour in one of the other regions.

I am just looking for a answer to a quick question, do you have to add buttons into every region to see them? I keep looking for information on how to kind of have a blank region so I can change the background color, but can't find anything(all the examples I find add buttons/text areas)? I am thinking I should be able to add something else other then a button or text area to the other regions that makes those regions show up and then I can work with them.

JP

Thanks guys for the info...as always your friendly and quick

cheers

JP

I am just doing some trial and error right now..really just spit balling some stuff....but I have researched and can't find anything to do what I am looking to do. Right now I have a JFrame created with a bunch of checkboxes and a button. I am trying to just create a simple game where the person who checks the last checkbox wins. I have the box created and have got it to disable any already checked checkboxes. I am thinking that when the button is clicked it would then do some code to randomly check some boxes (computer plays against the human.) I am at the point where I think I need to be able to read the all the JFrames components and then create some if statements to figure out if a)the component is a checkbox and b) if that checkbox is unchecked..check it. I have been trying to use getComponents() with no success. I am just hoping for a nudge in the right direction.

import java.awt.*; import javax.swing.*; import java.awt.event.*; public class LastManStanding extends JFrame implements ActionListener { JCheckBox one = new JCheckBox ("1"); JCheckBox two = new JCheckBox ("2"); JCheckBox three = new JCheckBox ("3"); JCheckBox four = new JCheckBox ("4"); JCheckBox five = new JCheckBox ("5"); JCheckBox six = new JCheckBox ("6"); JCheckBox seven = new JCheckBox ("7"); JCheckBox eight = new JCheckBox ("8"); JCheckBox nine = new JCheckBox ("9"); JCheckBox ten = new JCheckBox ("10"); JButton turn = new JButton("Complete Turn"); JLabel header = new JLabel ("Please select 1, 2, or 3 boxes."); JLabel footer = new JLabel ("Whoever selects the last box wins."); Font headerFont = new Font("Century", Font.PLAIN, 15); Font footerFont = new Font("Century", Font.PLAIN, 13); public LastManStanding() { final int FRAME_WIDTH = 220; final int FRAME_HEIGHT = 180; JFrame gameFrame = new JFrame("Last Man Standing"); gameFrame.setBounds(600,400,FRAME_WIDTH, FRAME_HEIGHT); header.setFont(headerFont); footer.setFont(footerFont); one.addActionListener(this); two.addActionListener(this); three.addActionListener(this); four.addActionListener(this); five.addActionListener(this); six.addActionListener(this); seven.addActionListener(this); eight.addActionListener(this); nine.addActionListener(this); ten.addActionListener(this); turn.addActionListener(this); gameFrame.setLayout(new FlowLayout()); gameFrame.add(header); gameFrame.add(one); gameFrame.add(two); gameFrame.add(three); gameFrame.add(four); gameFrame.add(five); gameFrame.add(six); gameFrame.add(seven); gameFrame.add(eight); gameFrame.add(nine); gameFrame.add(ten); gameFrame.add(turn); gameFrame.add(footer); gameFrame.setVisible(true); gameFrame.setSize(FRAME_WIDTH, FRAME_HEIGHT); } public static void main(String[] args){ LastManStanding game = new LastManStanding(); System.out.println(game.getComponents()); } public void actionPerformed(ActionEvent e) { Object source = e.getSource(); if(source instanceof JCheckBox) { ((JCheckBox) source).setEnabled(false); } if (source instanceof JButton) { System.out.println("button is triggering this"); //this is where I would put the code to get the components and this is where I have been testing things } } }

Thanks for the tips...when I load up my work laptop later tonight I will definitly play with the file and try your suggestions...much appreciated.

I am working on a program and am 95% done, but am stuck. My program creates a file and the user can file it with account ID's and balances. The issue I am having is that when a user enters a duplicate account ID it needs to throw an error and I am thinking after the error it should then ask for more ID's. At this point I can enter all the ID's I want and after I enter a duplicate entry it does throw the error, but then the program exits. How do I get it to continue asking for ID's.....any hints?

import javax.swing.*; import java.io.*; public class CreateBankFile { public static void main (String[] args) throws IOException, DuplicateAccountException { int pos; RandomAccessFile bankFile = new RandomAccessFile("BankFile.dat", "rw"); int accountID=0; double balance=0.0; int duplicate=0; final int MAXSIZE = 12; final int MAXRECORDS = 9999; final int END = 99999; try { for (int counter = 0; counter <MAXRECORDS; ++counter) //creates my blank entries I need { bankFile.writeInt(0); bankFile.writeDouble(0.0); } } catch(IOException exception) { System.out.println("Error: " + exception.getMessage()); } finally { bankFile.close(); } bankFile = new RandomAccessFile("BankFile.dat", "rw"); try { accountID = Integer.parseInt(JOptionPane.showInputDialog( null, "Enter customers account ID or " + END + " to quit program.")); //intake account ID while(accountID != END) { for(int x = 0; x < MAXRECORDS; ++x) //search the file for a duplicate entry { bankFile.seek(x*MAXSIZE); duplicate=bankFile.readInt(); if(duplicate==accountID) { throw(new DuplicateAccountException()); //throw error is duplicate found } else { continue; //no duplicates continue on to next if statement } } if((accountID>=0) &&(accountID<=MAXRECORDS)) /* * below I do not have issues if it makes it this fare below works, the * issue I have is after finding one duplicate it just ends the program and bypasses trying to enter more ID's */ { balance = Double.parseDouble(JOptionPane.showInputDialog( null, "Enter customers balance")); pos=accountID; bankFile.seek(pos*MAXSIZE); bankFile.writeInt(accountID); bankFile.writeDouble(balance); accountID = Integer.parseInt(JOptionPane.showInputDialog( null, "Enter customers account ID or " + END + " to quit program.")); } else { JOptionPane.showMessageDialog( null, "Account ID not valid, must be between 1 and 10000."); accountID = Integer.parseInt( JOptionPane.showInputDialog(null, "Enter customers account ID or " + END + " to quit program.")); } } } catch(DuplicateAccountException dae) { JOptionPane.showMessageDialog(null,"Account ID already entered"); } catch(IOException exception) { System.out.println("Error: " + exception.getMessage()); } finally { bankFile.close(); JOptionPane.showMessageDialog(null, "Exiting Program"); } } } [edit]Break long lines and change // comments to /* */ to reduce horizontal scrolling CR[/edit]

seems I make progress...need help..make some progress..and need more help....I am getting a nullPointerException for a project I am doing...I want to display all the info in each object that is in each order, so I got it to work if I fill the max number of items out, but if I don't fill the array it throws a nullPointer. I tried using a counter whenever a object was added and then during the display function just looping through with the max being that counter, but that did not seem to work. Any suggestions

import javax.swing.*; public class GadgetOrderTaker { private static int custID = 100; private static String inputName=""; private static String inputAddress=""; private static int orderInput; private static int orderNum; public static void main (String[] args){ Gadget[] item = new Gadget[5]; item[0] = new Gadget(101, "Electic hand warmer", 12.99); item[1] = new Gadget(124, "Batter-operated plant waterer", 7.55); item[2] = new Gadget(256, "Gerbil trimmer", 9.99); item[3] = new Gadget(512, "Talking Bookmark", 6.89); Order[] order1 = new Order[4]; //create array of 4 order objects for(int j=0;j<=3;j++){ //loop to create 4 order custID = custID +1; //maybe can be used for changing customer order ID later int qty=0; double tempFinalPrice = 0.00; order1[j] = new Order(custID); for (int x = 0; x <= 3; x++) //loop to fill the 4 objects with user input { orderInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Which item would you like to order?\n" + "101 - Electric hand warmer - $12.99\n" + "124 - Battery operated plant warmer - 7.55\n" + "256 - Gerbil trimmer - 9.99\n" + "512 - Talking bookmark - 6.89\n" + "Enter item number only.")); if(orderInput==101) //this if statment is used to choose which gadget object to put in the order array { order1[j].items[x][0] = item[0]; } else if(orderInput==124) { order1[j].items[x][0] = item[1]; } else if(orderInput==256) { order1[j].items[x][0] = item[2]; } else if(orderInput==512) { order1[j].items[x][0] = item[3]; } else if (orderInput==999) { JOptionPane.showMessageDialog(null,"Ending order"); break; } qty=Integer.parseInt(JOptionPane.showInputDialog(null,"Who many would you like?")); //creates a Integer object for qty to go in 2 dimensional array in the order object Integer intObj1 = new Integer(qty); order1[j].items[x][1] = intObj1; tempFinalPrice+=((Gadget)order1[j].items[x][0]).getPrice()*((Integer)order1[j].items[x][1]); order1[j].setTotalPrice(tempFinalPrice); } } for(int q = 0; q<=3; q++) { String gadgetInfo=""; for (int u = 0; u<=3; u++) // This for loop throws the exception if I don't have 4 items { gadgetInfo=gadgetInfo + ((Gadget)order1[q].items[u][0]).getItem() +" " + ((Gadget)order1[q].items[u][0]).getDesc() + " " + ((Gadget)order1[q].items[u][0]).getPrice(); } JOptionPane.showMessageDialog(null,"Order ID: " + order1[q].getOrderID() + "\n" + "Customers Name: " + order1[q].getCustName() + "\n" + "Customer Address: " + order1[q].getCustAddress() + "\n" + gadgetInfo ); } } }

I just want to say thanks guys...I went back and reviewed static variables and from what I understand now is that because they where static it was only making one variable and all the objects I was making where accessing the one variable. I say this only because maybe I am still wrong, but once I read that I cleaned up the top of my file and moved the variables to a different spot and it now works

import javax.swing.*; public class GadgetOrderTaker { private static int custID = 100; private static String inputName=""; private static String inputAddress=""; private static int orderInput; private static int orderNum; public static void main (String[] args){ Gadget[] item = new Gadget[4]; item[0] = new Gadget(101, "Electic hand warmer", 12.99); item[1] = new Gadget(124, "Batter-operated plant waterer", 7.55); item[2] = new Gadget(256, "Gerbil trimmer", 9.99); item[3] = new Gadget(512, "Talking Bookmark", 6.89); Order[] order1 = new Order[4]; //create array of 4 order objects for(int j=0;j<=3;j++){ //loop to create 4 order custID = custID +1; //maybe can be used for changing customer order ID later int qty=0; double tempFinalPrice = 0.00; //[b]removed the static part and moved them here where it starts a new order object and my thinking was when //it creates a new object..it will now have its own variables[/b] order1[j] = new Order(); for (int x = 0; x <= 3; x++) //loop to fill the 4 objects with user input { orderInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Which item would you like to order?\n" + "101 - Electric hand warmer - $12.99\n" + "124 - Battery operated plant warmer - 7.55\n" + "256 - Gerbil trimmer - 9.99\n" + "512 - Talking bookmark - 6.89\n" + "Enter item number only.")); if(orderInput==101) //this if statment is used to choose which gadget object to put in the order array { order1[j].items[x][0] = item[0]; } else if(orderInput==124) { order1[j].items[x][0] = item[1]; } else if(orderInput==256) { order1[j].items[x][0] = item[2]; } else if(orderInput==512) { order1[j].items[x][0] = item[3]; } else if (orderInput==999) { JOptionPane.showMessageDialog(null,"Ending order"); break; } qty=Integer.parseInt(JOptionPane.showInputDialog(null,"Who many would you like?")); //creates a Integer object for qty to go in 2 dimensional array in the order object Integer intObj1 = new Integer(qty); order1[j].items[x][1] = intObj1; System.out.println(((Gadget)order1[j].items[x][0]).getPrice() + "Quantity is: " + order1[j].items[x][1] + "\n"); //system outs to test what the variables are tempFinalPrice+=((Gadget)order1[j].items[x][0]).getPrice()*((Integer)order1[j].items[x][1]); order1[j].setTotalPrice(tempFinalPrice); System.out.println(order1[j].getTotalPrice()); } } } }

Ralph Cook wrote:It would help if you could point to a line of code or an output that shows your error. Otherwise, to help you, I first have to figure out what you mean by "when the loop is done" and where you're creating this object and what evidence you have that the amount is incorrect.

rc

I have updated the file with some comments on what is going on in the GadetOrderTake file, and below is the output when I try to do the orders...

12.99Quantity is: 1

12.99
7.55Quantity is: 1

20.54
9.99Quantity is: 1

30.53
6.89Quantity is: 1

37.42

Above is the first object and I just have system outs showing the price of the item orders, the quantity and the total price at that time, as you can see I am entering just 1 of the item and the total price is going up fine, but below is where the new object is created (so it asks for a new customer name and address) and then the total price just keeps going up where I would expect instead of 47.41 I would see 9.99

9.99Quantity is: 1

47.410000000000004

I am working on a school assignment and I have run into an issue where I am creating 4 objects and in each object I have to get a total price of all the items in the order. So I create 4 order objects and I fill it with information, one of the items is "final price" and for the first object everything is fine the total keeps going up as needed, but when the loop is done and a new object is created the new object keeps the "final price" value and does not reset back to zero. I thought when a new object was created it would go back to zero and start a new final price value. Can anyone take a look at this file and see if I am doing something wrong (which I am sure I am)

import javax.swing.*; public class GadgetOrderTaker { private static int custID = 100; private static String inputName=""; private static String inputAddress=""; private static int orderInput; private static int qty; private static int orderNum; protected static double total = 0.00; protected static double tempPrice = 0.00; protected static double tempFinalPrice = 0.00; protected static int tempQty=0; public static void main (String[] args){ Gadget[] item = new Gadget[4]; item[0] = new Gadget(101, "Electic hand warmer", 12.99); item[1] = new Gadget(124, "Batter-operated plant waterer", 7.55); item[2] = new Gadget(256, "Gerbil trimmer", 9.99); item[3] = new Gadget(512, "Talking Bookmark", 6.89); Order[] order1 = new Order[4]; //create array of 4 order objects for(int j=0;j<=3;j++){ //loop to create 4 order custID = custID +1; //maybe can be used for changing customer order ID later order1[j] = new Order(); for (int x = 0; x <= 3; x++) //loop to fill the 4 objects with user input and Gadget objects { orderInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Which item would you like to order?\n" + "101 - Electric hand warmer - $12.99\n" + "124 - Battery operated plant warmer - 7.55\n" + "256 - Gerbil trimmer - 9.99\n" + "512 - Talking bookmark - 6.89\n" + "Enter item number only.")); if(orderInput==101) //this if statment is used to choose which gadget object to put in the order array { order1[j].items[x][0] = item[0]; } else if(orderInput==124) { order1[j].items[x][0] = item[1]; } else if(orderInput==256) { order1[j].items[x][0] = item[2]; } else if(orderInput==512) { order1[j].items[x][0] = item[3]; } else if (orderInput==999) { JOptionPane.showMessageDialog(null,"Ending order"); break; } qty=Integer.parseInt(JOptionPane.showInputDialog(null,"Who many would you like?")); //creates a Integer object for qty to go in 2 dimensional array in the order object Integer intObj1 = new Integer(qty); order1[j].items[x][1] = intObj1; System.out.println(((Gadget)order1[j].items[x][0]).getPrice() + "Quantity is: " + order1[j].items[x][1] + "\n"); //system outs to test what the variables are tempFinalPrice+=((Gadget)order1[j].items[x][0]).getPrice()*((Integer)order1[j].items[x][1]); //create a tempTotalPrice from the gadget item and qty entered order1[j].setTotalPrice(tempFinalPrice); //pass the tempFinalPrice to the order object and set it System.out.println(order1[j].getTotalPrice()); //retrieve the Total price that I believe should reset to 0.00 when a new object is created. } } } }

If you want the other files to do this here they are:

import javax.swing.*; public class Gadget { private int item; private String desc; private double price; public Gadget(int i, String d, double p) { item=i; desc=d; price=p; } public int getItem() { return item; } public String getDesc() { return desc; } public double getPrice() { return price; } }

import javax.swing.*; public class Order { protected int orderID; protected Object[][] items = new Object[4][2]; protected String custName; protected String custAddress; protected double totalPrice; protected double shipFee; public Order() { custName=JOptionPane.showInputDialog(null, "What is the customers name?"); custAddress=JOptionPane.showInputDialog(null, "What is the customers street address?"); orderID=0; totalPrice=0; shipFee=0.00; } public void displayPrice() { System.out.println(items[0][0]); } public void displayShipFee() { System.out.println(shipFee); } public double setShipFee() { if ((totalPrice >= 0) && (totalPrice <= 24.99)) { shipFee=5.55; } else if ((totalPrice >= 25) && (totalPrice <= 49.99)) { shipFee=8.55; } else { shipFee=11.55; } return shipFee; } public double getTotalPrice() { return totalPrice; } public void setTotalPrice(double price) { totalPrice=price; } public int getOrderID() { return orderID; } public String getCustName() { return custName; } public String getCustAddress() { return custAddress; } public double getShipFee() { return shipFee; } }

fred rosenberger wrote:If you know your array needs to hold four items, I'd declare it as a member variable...

public class Order { private int [] orderID; protected String custName; protected String custAddress; private double totalPrice; private double shipFee; ...
then your constructor would be something like

public Order (int [] orders) { orderID = new int[4]; if orders.length > 4 //there is a problem else for (int i = 0; i < orders.length; i++ { orderID[i] = orders[i]; } }
(note - i'm working on a loaner pc, which does not have the JDK installed, so I can't test/verify my example)

Obviously you'd need to adjust it to pass in the other params, but this might give you a few ideas.

Once again thanks a bunch Fred, while working on it today I have changed my GadgetOrderTaker file to the following:
import javax.swing.*; public class GadgetOrderTaker { private static int custID = 100; private String inputName=""; private String inputAddress=""; private static int orderInput; private static int qty; private static int orderNum; public static void main (String[] args){ Gadget[] item = new Gadget[4]; item[0] = new Gadget(101, "Electic hand warmer", 12.99); item[1] = new Gadget(124, "Batter-operated plant waterer", 7.55); item[2] = new Gadget(256, "Gerbil trimmer", 9.99); item[3] = new Gadget(512, "Talking Bookmark", 6.89); Order order1 = new Order(); for (int x = 0; x <= 3; ++x) { orderInput = Integer.parseInt(JOptionPane.showInputDialog(null, "Which item would you like to order?\n" + "101 - Electric hand warmer - $12.99\n" + "124 - Battery operated plant warmer - 7.55\n" + "256 - Gerbil trimmer - 9.99\n" + "512 - Talking bookmark - 6.89\n" + "Enter item number only.")); if(orderInput==999) { JOptionPane.showMessageDialog(null,"Ending order"); break; } order1.items[x][0] = orderInput; qty=Integer.parseInt(JOptionPane.showInputDialog(null,"Who many would you like?")); order1.items[x][1] = qty; } System.out.println(order1.items[0][0] + " Quantity: " + order1.items[0][1]); System.out.println(order1.items[1][0] + " Quantity: " + order1.items[1][1]); System.out.println(order1.items[2][0] + " Quantity: " + order1.items[2][1]); System.out.println(order1.items[3][0] + " Quantity: " + order1.items[3][1]); } }

the reason I came up with this is that now everytime I create a Order object it would then fill it with a item number and matching quantity. I am testing with just one object right now and am working on a good way to automatically create another object that I can then fill again with the same info. Once I am able to create 4 seperate Order objects with upto 4 items with quantity I am thinking I can start to build around them with regards to calculating total price/S&H/etc.

I post this because if you see an issue maybe I might be heading int that would be great....thanks again for the continued input

fred rosenberger wrote:I'm not sure I can answer all your questions, but...

A "list of item numbers ordered (up to four)" to me sounds like you'd want an array of size four. you'll need methods to add or delete items, and to make sure you don't try and add a fifth.

Alternatively, you could just have four integers called something like "orderId1", "orderID2", etc. you could have specific methods for adding or deleting each of the four, plus a method for getting each. Using an array could be simpler, and make your life easier if next week you need to update it to have 8 orders (or 12, or 2000).

My PERSONAL opinion would be you should NOT have a variable holding the price of all items. If you have a list of the items, you should calculate the total when you need it. If you have a variable, you need to do a lot more updating each and every time an item is added or deleted, and you're data can become out of sync if that gets messed up.

Another tip would be to not store prices as floats. you are dooming your code to weird rounding issues. Money should be stored as an atomic unit, which (for the U.S.) is pennies. Then you can re-format it as needed when you want to print/display it.

Thanks for the info Fred, unfortunately I have to have a variable to hold the total price as the project says it needs it. I agree with the array size four for the list, but when I thought of that it made me think of more questions...such as do I create a array of size four in the Order constructor then? that sounded incorrect to me, but the project says "Include a constructor to set the field values" so I am think I need to set the array somehow and for some reason....the array of item numbers would have to be based on input from the user, so how would that work? I am re reading the array, "methods, classes, and objects" chapters as I think they might help me out in this situation....