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Card - Deck - Hand Java Project

I know everyone gets skeptical whenever people put homework on here but I've run out of options and could really use some direction. I have a project where I have to create a deck of cards and allow the user to pick the size of the hand and then fill that hand with random cards and display that to the user. I've found plenty of answers using ArrayLists but mine requires an array and I've tried everything I know and my code is either completely wrong or throws a bunch of errors.
So here are the problems I have:
1) The addCard method in the Hand class can be used to add one Card object at a time to the hand array until it is full. It should increment the cardsInHand counter each time a Card object is added to the Hand as long as there is room for the Card to fit into the Hand.
Here is the code for the Hand class:
public class Hand
{
private int handSize; //Holds the size of the hand
private int cardsInHand; //Holds the number of cards allowed in the hand
private Card[] hand; //Array of card objects
public Hand()
{
this.handSize = 5;
this.cardsInHand = 0;
this.hand = new Card[52];
}//end Default Constructor
public Hand(int handSize)
{
this.handSize = handSize;
}//end Parameterized Constructor
public Hand(Hand handIn)
{
this.handSize = handIn.handSize;
this.cardsInHand = handIn.cardsInHand;
this.hand = handIn.hand;
}//end Copy Constructor
public void addCard(Card card)
{
hand[card]; //--> throws a type mismatch exception (change card param to an int)
}//end addCard()
public int getHandSize()
{
return handSize;
}
public void setHandSize(int handSize)
{
this.handSize = handSize;
}
public int getCardsInHand()
{
return cardsInHand;
}
public void setCardsInHand(int cardsInHand)
{
this.cardsInHand = cardsInHand;
}
public Card[] getHand()
{
return hand;
}
public void setHand(Card[] hand)
{
this.hand = hand;
}
public String toString()
{
String msg = "";
return msg;
}//end toString()
}//end class
My addCard method is just all janky and I could really use some help trying to fill it so my program works. Any help or even a pointing in the right direction would be appreciated!

My addCard method is just all janky and I could really use some help trying to fill it so my program works. Any help or even a pointing in the right direction would be appreciated
Sometimes the best thing to do is stop, turn the screen off, get a pen and piece of paper and just nut it out without any code. Try to understand the problem and get the logic straight in your head.
Basically, you have a series of buckets into which you can put a Card. Before you can put a Card in a bucket, you need to know if you have any free buckets available.
If there are, you need to add the Card to the next available bucket (which should be pointed to by cardsInHand) and increment cardsInHand
Your error is because you're trying reference a "bucket" using a Card, but you can only reference a "bucket" by an index (number) so...
hand[card];
should be more like...
hand[cardsInHand] = card;
but only after you've determined if there is a free "bucket" available, and you should increment cardsInHand AFTER this statement
I'd also be worried about your constructors
public Hand(int handSize)
{
this.handSize = handSize;
}//end Parameterized Constructor
isn't initialising hand, so that's going to be null. A better solution might be to use existing constructors where possible to build a common "initialisation" path
public Hand() {
this(5);
}//end Default Constructor
public Hand(int handSize) {
this.handSize = handSize;
this.cardsInHand = cardsInHand;
this.hand = new Card[handSize];
}//end Parameterized Constructor
Also
public Hand(Hand handIn)
{
this.handSize = handIn.handSize;
this.cardsInHand = handIn.cardsInHand;
this.hand = handIn.hand;
}//end Copy Constructor
is worrying, as it's possible for some external class to make a change to handIn's hand and that change will be reflected by this instance as well (as they are pointing to the same array).
A "copy" constructor should be making a "copy" of the data. Realistically, this should probably be a "deep" copy, so any changes to Card don't mess with the Hand as well, but I'll start with a simple "shallow" copy to get you started
public Hand(Hand handIn) {
this.handSize = handIn.handSize;
this.cardsInHand = 0;
this.hand = new Card[this.handSize];
// Yes, I know there is a better way to do this, but
// I want the OP to learn something
for (int index = 0; index < handIn.hand.length; index++) {
Card card = handIn.hand[index];
if (card != null) {
hand[cardsInHand] = card;
cardsInHand++;
}
}
}//end Copy Constructor

#MadProgrammer already give better answer, I only want to chime a little. Knowing the OP project assignment using Java I want to comment a little about the Hand class design.
The task clearly said that user can pick hand with custom size, then the user will add card into the hand until the hand is full. Thus, I would propose the Hand class design like below.
public class Hand {
private int size; // Hold the amount of card can be hold by hand.
private int counter; // Count how many card added.
private Card[] cards; // The card on hand.
public Hand(int size) {
this.counter = 0;
this.size = size;
this.cards = new Card[size];
}
public void addCard(Card card) {
if (this.counter > this.size) {
throw new IllegalStateArgument("The hand is full of card!");
}
this.cards[this.counter] = card;
this.counter++;
}
public String show() {
StringBuilder result = new StringBuilder("The card on hand is: \n");
for (int i=0; i<this.size; i++) {
result.append(this.cards[i].toString()).append("\n");
}
return result.toString();
}
}
In my opinion the Hand class more easy to understand and achieve the goals of the Hand purpose from the task. However, just use this as reference and write code that you understand well.

Using array to minimize variable usage

In the interest of not creating more variables than necessary and cluttering up within the scope of a method that could otherwise have been very slim, I've, instead, created a temporary to hold all of the files I'm going to be referencing throughout the rest of the method.
I dislike this solution because it creates an array object every time it is run when an array object is not necessary to be created.
I could also not use the array or wall of variables, and instead reference the get methods directly, but that creates a lot of redundancy as I am performing the same methods repeatedly, and I dislike that even more.
public void savePrices() {
MFilePrices file[] = {AutoEcon.files().getPrices(), AutoEcon.files().getIntangibles(), AutoEcon.files().getGroups()};
for (String price : sellPrices.keySet()) {
if (EconItem.fromString(price) != null) {
file[0].setPrice(price, sellPrices.get(price).getExpression());
file[0].setBuyRate(price, sellPrices.get(price).getBuyRate());
} else if (file[1].getLabels().contains(price)) {
file[1].setPrice(price, sellPrices.get(price).getExpression());
file[1].setBuyRate(price, sellPrices.get(price).getBuyRate());
} else if (file[2].getLabels().contains(price)) {
file[2].setPrice(price, sellPrices.get(price).getExpression());
file[2].setBuyRate(price, sellPrices.get(price).getBuyRate());
}
}
}
public Double setExpression(String id, String expr) {
savePrices();
MFilePrices file[] = {AutoEcon.files().getPrices(), AutoEcon.files().getIntangibles(), AutoEcon.files().getGroups()};
if (EconItem.fromString(id) != null)
file[0].setPrice(id, expr);
else if (file[1].getLabels().contains(id))
file[1].setPrice(id, expr);
else if (file[2].getLabels().contains(id))
file[2].setPrice(id, expr);
else return null;
sellPrices.clear();
total=0;
loadPrices(AutoEcon.plugin());
return sellPrices.get(id).getPrice();
}
Another solution could be to create an array within the FilePool class where I'm getting the files from, which contains those three configuration files, or a method which puts them into an array and sends over the array. However, the latter just moves the problem over to another class, and the former is still creating a single array that is not totally necessary.
Both of these solutions just moves the problem from one class to another.
public class FilePool {
private Config config;
private Prices prices;
private Intangibles i;
private Groups groups;
private Logs econLogs;
private ItemAliases a;
public FilePool(AutoEcon pl) {
config = new Config(pl);
prices = new Prices(pl);
i = new Intangibles(pl);
econLogs = new Logs(pl);
a = new ItemAliases(pl);
new ReadMe(pl);
}
public Config getConfig() {
return config;
}
public Prices getPrices() {
return prices;
}
public Groups getGroups() {
return groups;
}
public Intangibles getIntangibles() {
return i;
}
public Logs getLogs() {
return econLogs;
}
public ItemAliases getAliases() {
return a;
}
}
(Ignore the dumb variable names in the FilePool class, I just loved the fact that they all line up so perfectly. Will be naming appropriately before publishing)
I know I'm being a bit over-anal about this tiny thing that won't affect the running program at all, but after being constantly harassed for every minor detail of my code by my colleagues in the past, I've grown to be a bit of a perfectionist.
Thanks to anyone who spent their time reading this. <3

The creation of the array is not a problem. Resources to create an array are meaningless. What is more of a problem is that anyone reading your code will struggle to understand what the magic indices represent without referring back to the array. Which means that you should turn them into named constants which will complicate your code even further.
Much better is to have clear variable names that represent what each element represents. Also a good idea to iterate through the map so you can avoid getting the value for each item:
FilePool files = AutoEcon.files();
final MFilePrices prices = files.getPrices();
final MFilePrices intangibles = files.getIntangibles();
final MFilePrices groups = files.getGroups();
sellPrices.forEach((price, value) -> {
if (EconItem.fromString(price) != null) {
setPriceAndBuyRate(prices, price, value);
} else if (intangibles.getLabels().contains(price)) {
setPriceAndBuyRate(intangibles, price, value);
} else if (groups.getLabels().contains(price)) {
setPriceAndBuyRate(groups, price, value);
}
});
private void setPriceAndBuyRate(MFilePrices filePrices, Price price, Value value) {
filePrices.setPrice(price, value.getExpression());
filePrices.setBuyRate(price, value.getBuyRate());
}
If you're concerned that the number of variables make the method difficult to read then move the logic for comparing the price to the labels and setting the price and buy rate into a separate class. That's a good practice in any case as it gives the class a single reason to change.

I keep running into the same problems every time I try to make a new program

My current program is a simple game.. I am trying to make it to help figure out how to properly use OOP. But every time I get a little bit into a new program I run into the same problem:
I make an instance to use in my game. This instance could be anything - the main hero, a monster, whatever. Everything is going good, the instance is exactly what I want it to be. Maybe I manipulate it a little bit.
I then try to use a different class, I guess I create an instance of a different class, in an attempt to further manipulate the original instance. Maybe I originally created my hero and changed his stats, and now at this point I am trying to have my hero say something based on the stats that were chosen.
This point is always where I hit a roadblock. I can't seem to do what I want to do here - I can't use that original instance I made because It was just an instance and I don't know how to manipulate it(or even if I am supposed to) from within a new class.
So.. it's a fundamental design problem/lack of understanding of OOP.
But I feel like I have a decent grasp on how to actually program stuff.. I keep reading and reading and getting advice but I can't seem to get past this barrier.
I know people on this site don't seem to like posts like this but maybe someone here can Identify with what it is I am not grasping.
Here is an example of what I am talking about, the game I am trying to make right now.
package pkgnew.stupid.game;
import java.util.Scanner;
/**
*
* #author whyguy2
*/
public class Hero {
public static int heroattack = 1;
public static int herospeed = 1;
public static int heroarmorpen = 1;
public static int heroarmor = 1;
public static int herohealth = 5;
public static String inputstat;
public static int herothepoints = 0;
Hero(int points){
spendpoint(points);
}
public void attack(){
}
public void die(){
System.exit(0);
}
public void winbattle(){
System.out.println("You win the battle and have one new point to spend!");
spendpoint(1);
new NewEncounter();
}
public void levelup(){
System.out.println("You have leveled up and receive 5 new points to spend");
spendpoint(5);
new NewEncounter();
}
public void spendpoint(int points){
for(int x=0; x<points; x++){
System.out.println("Available Points: " + points);
System.out.println("Available Attributes:");
System.out.println("attack: " + heroattack);
System.out.println("speed: " + herospeed);
System.out.println("armorpen: " + heroarmorpen);
System.out.println("armor: " + heroarmor);
System.out.println("health: " + herohealth);
System.out.println(points);
System.out.println(x);
Scanner keyboard = new Scanner( System.in );
inputstat = keyboard.next( );
if(inputstat.equals("attack")){
heroattack = heroattack + 1;
}
else if(inputstat.equals("speed")){
herospeed = herospeed + 1;
}
else if(inputstat.equals("armorpen")){
heroarmorpen = heroarmorpen + 1;
}
else if(inputstat.equals("armor")){
heroarmor = heroarmor + 1;
}
else if(inputstat.equals("health")){
herohealth = herohealth + 5;
}
else{
System.out.println("Please pick one of the stats");
x = x-1;
}
}
}
}
public class StartGame {
StartGame(){ //runs through output for a new game
System.out.println("Welcome to the game");
System.out.println("Pick your hero's starting stats");
Hero thishero = new Hero(10); //spends your points
System.out.println("Let's Begin!/n/n");
new NewEncounter(); //goes into the encounter loops
}
}
at this point I I try to program an encounter in the NewEncounter class, but that isn't possible because I can't use that instance of my hero that I created. and I am pretty sure that my design is bad in the first place, I think I have read that you should be trying to use static variables as little as possible in the first place. I am still reading trying to grasp this but I have read a lot and I feel like nothing is helping me. I actually think a more "hands on" large scale project/tutorial might help me, but I don't know one. Anyways thanks for any help and sorry for the long/blog-like post.

The standard way to use an instance of one class within another is to either store a reference to it or to pass it into the method that stores or uses it.
For example:
class Encounter {
private final Hero mainHero;
private final List<Hero> participants;
public Encounter(Hero mainHero) {
this.mainHero = mainHero;
participants = new ArrayList<>();
}
public void addParticipant(Hero hero) {
participants.add(hero);
}
}
Allows:
Encounter encounter = new Encounter(hero);
or:
encounter.addParticipant(hero);
These can then be used within the class. For example:
class Encounter {
public void moveAllParticipants() {
participants.forEach(Hero::move);
}
}
I notice you have used a lot of public static class variables. This is unusual and there are few good reasons to use them. One is to define constants. If that's your intent then I suggest you use the following standard form:
private static final int HERO_ATTACK = 1;
If you intend for these to be instance variables (i.e. different for each hero) then they should not be static nor public.
This is the sort of area that is well covered in the various Java tutorials. I suggest working through one of them and coming back here if you have further issues.

sorting a string array and an int array [closed]

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Closed 9 years ago.
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I am working on making a dating website on java. I want to find the three most compatible matches for a user. So i have an array of three ints and if a user is more compatible the least compatible score will be replaced. I do this using selection sort. I also need the references to be correct so i Can return the proper names. I can't figure our how to sort the string array. Thanks for the help and heres the code:
public void findMatches(String matchName)
{
String nameA = null;
String nameB = null;
String nameC = null;
int matchA = -1;
int matchB = -2;
int matchC = -3;
Member ref = userList.get(matchName);
if(ref.getDesiredAge()>=45 && ref.getDesiredSex().equalsIgnoreCase("Male"))
{
for(String na : userListMaleOld.keySet())
{
Member refA = userListMaleOld.get(na);
int numberOfMatches=findQuestionMatches(ref, refA);
int [] counts = {matchA, matchB, matchC};
String [] names = {nameA, nameB, nameC};
counts = doSelectionSort(counts);
if(numberOfMatches>counts[0]);
{
counts[0] = numberOfMatches;
?!?!?!?!?!??!??!??!WHAT HERE?!?!
}

Use a Map instead.
Concrete this means that you can do something like this:
Map<User, Integer> bestMatches = new HashMap<>();
void validateUser(User user, int value) {
if(bestMatches.size() < 3) {
bestMatches.put(User, 3);
return;
}
Map<User, Integer> newMap = new HashMap<User, Integer>();
User minValue = Collections.min(bestMatches.values());
if(value > minValue) {
for(Map.Entry<User, Integer> entry: bestMatches.entrySet()) {
if(entry.getValue() != minValue) {
newMap.put(entry.getKey(), entry.getValue());
}
}
newMap.put(user, value);
}
bestMatches = newMap;
}
It's probably not very optimized, but you can fix that as you wish. Basically just check if the value of the current user is higher than the lowest value among the existing users in the collection. If it is, create a new collection with the 2 other users and assign that to your first collection.
For large datasets this would be impractical, but we're talking about 3 users here so it shouldn't be an issue.

If these are actually supposed to be name / score pairs (i.e. scoreA is the score for nameA, scoreB is the score for nameB and so on), then the simple solution is something like this:
public class Score {
private String name;
private int score;
// Declare a constructor and getters
}
... and to use this appropriately. For instance, you could now sort a list or array of these Score objects, by name or by score.
Unfortunately, it is not possible to figure out what the code you've shown us is supposed to do, and how it is supposed interact with the rest of your code. Therefore, it is not entirely clear how you should modify your code to use this. And it maybe that you are best of starting over following Jeroen's advice and completely redesigning your data structures.

Java - Add an object to an arraylist, then adding another to the arraylist causes the first element to be overwritten

I'm currently doing my third year programming project and its a folio tracker. :/ I have crated Stock_API and Portfolio_API interfaces (and implementations of them) and a GUI class which when instantiated takes two parameters as so:
public GUI(Portfolio_API p, Stock s){
tempPort = p;
tempStock = s;
}
I use this constructor as a way of getting implementations of these interfaces into the GUI without exposing the implementation to the GUI (which is one of the main objectives of this project). A portfolio object has a name(string) and an ArrayList. A stock object has a ticker symbol(string), a stock name(string), a share value(float), a number of shares(int) and a value of holding(float).
In the GUI i have a portCollection array list which holds objects of type portfolio_API and this is so the system can keep track of multiple portfolios. Also as mentioned in the block of code above has a tempStock and tempPort object.
Sorry to give u so much detail about the program but i thought it best so i could get the context across. Anyway, the problem at hand. I have a method which uses the GUI to get a ticker symbol, a stock name and a number of shares and adds the stock to the current portfolio open(each portfolio has its own tab). The method looks like this:
public void addStock() {
int num_shares = 0;
float dailyChange = 0.0f;
float stockValue = 0.0f;
boolean succeed = true;
// GUI gets information of stock from user
String ticker = JOptionPane.showInputDialog(frame,
"Enter the ticker symbol:");
String stockName = JOptionPane.showInputDialog(frame,
"Enter the Stock name:");
try {
num_shares = Integer.parseInt(JOptionPane.showInputDialog(frame,
"Enter the number of shares:"));
} catch (NumberFormatException e) {
JOptionPane.showMessageDialog(frame,
"Number of shares was not an integer. Try again");
succeed = false;
}
// If parsing was successful...
if (succeed) {
tempStock.setTicker(ticker);
tempStock.setNumberOfShares(num_shares);
tempStock.setStockName(stockName);
// Fetches newest value using the current ticker symbol
boolean succeedUpdate = tempStock.updateShareValue();
if (succeedUpdate) {
tempStock.calculateValueOfHolding();
// Adds to the current portfolio...
String tabName = tabbedPane.getTitleAt(tabbedPane
.getSelectedIndex());
System.out.println(tabName);
findPortfolio(tabName).addStock(tempStock);
findPortfolio(tabName).sort();
// ...Then adds it to the table
JPanel j = (JPanel) tabbedPane.getSelectedComponent()
.getComponentAt(0, 0);
JViewport v = ((JScrollPane) j.getComponent(0)).getViewport();
JTable table = (JTable) v.getComponent(0);
float currentTotal = findPortfolio(tabName).getTotal();
// Updates the total label
((JLabel) j.getComponent(1)).setText("Total: " + currentTotal);
Object[] newStock = { tempStock.getTicker(),
tempStock.getStockName(),
tempStock.getNumberOfShares(),
tempStock.getShareValue(),
tempStock.getValueOfHolding() };
((DefaultTableModel) table.getModel()).addRow(newStock);
}
}
}
When I add more than one stock, the new stock takes place of the old one an effectively overwrites it. I think its the reuse of tempStock that is doing it. Not sure why though as surely if i add the variable to an arraylist it becomes part of that arraylist and needs no association with the tempStock variable?
Methods that are used with the mentioned arraylists :
private Portfolio_API findPortfolio(String name) {
Portfolio_API p = null;
for (int i = 0; i < portCollection.size(); i++) {
if (portCollection.get(i).getName() == name) {
p = portCollection.get(i);
}
}
These two are in the Portfolio class:
#Override
public boolean addStock(Stock_API s) {
if (!doesExist(s)) {
portfolio.add(s);
return true;
} else {
return false;
}
}
#Override
public boolean doesExist(Stock_API s) {
boolean found = false;
for (int i = 0; i < portfolio.size(); i++) {
if (portfolio.get(i).getTicker() == s.getTicker()) {
found = true;
}
}
return found;
}
I've only come here for help because i have hit a brick wall and I really need help. If anyone could give me any suggestions, i'd be eternally in your debt.
Thanks,
Chris

Yes, I think you are right when you say you think it's because you're reusing the tempStock variable. This variable still references the original object so calling setTicker() etc on tempStock also changes the object referenced by your ArrayList because it's the same object. Try reinitialising your tempStock and see if it makes a difference:
// If parsing was successful...
if (succeed) {
tempStock = new Stock(); // or however you instantiate this object
tempStock.setTicker(ticker);
tempStock.setNumberOfShares(num_shares);
tempStock.setStockName(stockName);

Thanks guys for all your input. #oracle certified professor helped with the stock problems after adding an overloaded method for addStock but turned out the same problems plagued portfolio.
What I did was create a makePortfolio method in Portfolio_API to create a new portfolio and return it. That way it avoids any nasty overwrite, gonna add it to stock too just now.
Thanks again guys. Good night! :)