Functional Scope (In-Scope)
- Complete Playing structures: Encapsulate Rank, Suit, and immutable Card representations cleanly.
- Fisher-Yates Shuffling: Distribute and randomize card array indexes uniformly.
- Poker Hand Classification: Evaluate 5-card combinations into ranked bands (Royal Flush, Straight Flush, Four of a Kind, etc.).
- Tie-Breaking Kickers logic: Resolve matching hands by evaluating outstanding high card kickers.
Explicit Boundaries (Out-of-Scope)
- No Pot betting loops: Excludes tracking chips balances or dealer bets calculations.
- No Multi-player Lobby: Bypasses live networks connections or server lobbies.
Clean reference designs demonstrating modular shufflers in Java and Python:
// ─── JAVA BLUEPRINT ──────────────────────────────────────────────────────────
import java.util.*;
import java.util.stream.Collectors;
enum Suit { SPADES, HEARTS, DIAMONDS, CLUBS }
enum Rank {
TWO(2), THREE(3), FOUR(4), FIVE(5), SIX(6), SEVEN(7), EIGHT(8), NINE(9), TEN(10),
JACK(11), QUEEN(12), KING(13), ACE(14);
private final int value;
Rank(int val) { this.value = val; }
public int getValue() { return value; }
}
enum HandRank {
HIGH_CARD(1), ONE_PAIR(2), TWO_PAIR(3), THREE_OF_A_KIND(4), STRAIGHT(5),
FLUSH(6), FULL_HOUSE(7), FOUR_OF_A_KIND(8), STRAIGHT_FLUSH(9), ROYAL_FLUSH(10);
private final int score;
HandRank(int score) { this.score = score; }
public int getScore() { return score; }
}
class Card implements Comparable<Card> {
private final Rank rank;
private final Suit suit;
public Card(Rank rank, Suit suit) {
this.rank = rank;
this.suit = suit;
}
public Rank getRank() { return rank; }
public Suit getSuit() { return suit; }
@Override
public int compareTo(Card other) {
return Integer.compare(this.rank.getValue(), other.rank.getValue());
}
@Override
public String toString() { return rank + " of " + suit; }
}
class Deck {
private final List<Card> cards = new ArrayList<>();
public Deck() { reset(); }
public synchronized void reset() {
cards.clear();
for (Suit s : Suit.values()) {
for (Rank r : Rank.values()) {
cards.add(new Card(r, s));
}
}
}
public synchronized void shuffle() {
Random rand = new Random();
for (int i = cards.size() - 1; i > 0; i--) {
int j = rand.nextInt(i + 1);
Card temp = cards.get(i);
cards.set(i, cards.get(j));
cards.set(j, temp);
}
}
public synchronized List<Card> deal(int count) {
List<Card> hand = new ArrayList<>();
for (int i = 0; i < count; i++) {
if (!cards.isEmpty()) {
hand.add(cards.remove(cards.size() - 1));
}
}
return hand;
}
}
class PokerHand implements Comparable<PokerHand> {
private final List<Card> cards;
private HandRank handRank;
private List<Integer> tieBreakers; // Sorted representation for kicker checks
public PokerHand(List<Card> cards) {
if (cards.size() != 5) throw new IllegalArgumentException("Must have exactly 5 cards.");
this.cards = new ArrayList<>(cards);
Collections.sort(this.cards);
evaluate();
}
public HandRank getHandRank() { return handRank; }
public List<Card> getCards() { return cards; }
private void evaluate() {
boolean isFlush = cards.stream().map(Card::getSuit).distinct().count() == 1;
boolean isStraight = checkStraight();
Map<Integer, Long> freq = cards.stream()
.collect(Collectors.groupingBy(c -> c.getRank().getValue(), Collectors.counting()));
List<Map.Entry<Integer, Long>> sortedFreq = freq.entrySet().stream()
.sorted((e1, e2) -> {
int c = Long.compare(e2.getValue(), e1.getValue());
if (c != 0) return c;
return Integer.compare(e2.getKey(), e1.getKey());
}).collect(Collectors.toList());
tieBreakers = sortedFreq.stream().map(Map.Entry::getKey).collect(Collectors.toList());
// Straight Adjustment for Ace-low (A, 2, 3, 4, 5)
if (isStraight && cards.get(4).getRank() == Rank.ACE && cards.get(0).getRank() == Rank.TWO) {
tieBreakers = Arrays.asList(5, 4, 3, 2, 1); // Rank the 5 high straight
}
if (isFlush && isStraight) {
if (cards.get(0).getRank() == Rank.TEN) {
handRank = HandRank.ROYAL_FLUSH;
} else {
handRank = HandRank.STRAIGHT_FLUSH;
}
} else if (sortedFreq.get(0).getValue() == 4) {
handRank = HandRank.FOUR_OF_A_KIND;
} else if (sortedFreq.get(0).getValue() == 3 && sortedFreq.get(1).getValue() == 2) {
handRank = HandRank.FULL_HOUSE;
} else if (isFlush) {
handRank = HandRank.FLUSH;
// Overwrite tieBreakers to sort card ranks descending
tieBreakers = cards.stream().map(c -> c.getRank().getValue())
.sorted(Comparator.reverseOrder()).collect(Collectors.toList());
} else if (isStraight) {
handRank = HandRank.STRAIGHT;
} else if (sortedFreq.get(0).getValue() == 3) {
handRank = HandRank.THREE_OF_A_KIND;
} else if (sortedFreq.get(0).getValue() == 2 && sortedFreq.get(1).getValue() == 2) {
handRank = HandRank.TWO_PAIR;
} else if (sortedFreq.get(0).getValue() == 2) {
handRank = HandRank.ONE_PAIR;
} else {
handRank = HandRank.HIGH_CARD;
tieBreakers = cards.stream().map(c -> c.getRank().getValue())
.sorted(Comparator.reverseOrder()).collect(Collectors.toList());
}
}
private boolean checkStraight() {
// Ace-low straight edge case
if (cards.get(0).getRank() == Rank.TWO && cards.get(1).getRank() == Rank.THREE &&
cards.get(2).getRank() == Rank.FOUR && cards.get(3).getRank() == Rank.FIVE &&
cards.get(4).getRank() == Rank.ACE) {
return true;
}
for (int i = 0; i < 4; i++) {
if (cards.get(i).getRank().getValue() + 1 != cards.get(i + 1).getRank().getValue()) {
return false;
}
}
return true;
}
@Override
public int compareTo(PokerHand other) {
int rankCompare = Integer.compare(this.handRank.getScore(), other.handRank.getScore());
if (rankCompare != 0) return rankCompare;
// Kickers check
for (int i = 0; i < this.tieBreakers.size(); i++) {
int comp = Integer.compare(this.tieBreakers.get(i), other.tieBreakers.get(i));
if (comp != 0) return comp;
}
return 0;
}
@Override
public String toString() {
return handRank + " [" + cards.stream().map(Card::toString).collect(Collectors.joining(", ")) + "]";
}
}
public class Main {
public static void main(String[] args) {
Deck deck = new Deck();
deck.shuffle();
List<Card> player1Cards = Arrays.asList(
new Card(Rank.ACE, Suit.HEARTS), new Card(Rank.KING, Suit.HEARTS),
new Card(Rank.QUEEN, Suit.HEARTS), new Card(Rank.JACK, Suit.HEARTS),
new Card(Rank.TEN, Suit.HEARTS)
);
List<Card> player2Cards = Arrays.asList(
new Card(Rank.ACE, Suit.SPADES), new Card(Rank.ACE, Suit.CLUBS),
new Card(Rank.KING, Suit.DIAMONDS), new Card(Rank.KING, Suit.SPADES),
new Card(Rank.TEN, Suit.CLUBS)
);
PokerHand hand1 = new PokerHand(player1Cards);
PokerHand hand2 = new PokerHand(player2Cards);
System.out.println("Player 1 Hand: " + hand1);
System.out.println("Player 2 Hand: " + hand2);
int comparison = hand1.compareTo(hand2);
if (comparison > 0) {
System.out.println("Player 1 Wins!");
} else if (comparison < 0) {
System.out.println("Player 2 Wins!");
} else {
System.out.println("Split Pot (Tie)!");
}
}
}