Deck.java

/*******************************************************************************
 * Companion code for the book "Introduction to Software Design with Java",
 * 3rd edition by Martin P. Robillard.
 *
 * Copyright (C) 2025 by Martin P. Robillard
 *
 * This code is licensed under a Creative Commons 
 * Attribution-NonCommercial-NoDerivatives 4.0 International License.
 * 
 * See http://creativecommons.org/licenses/by-nc-nd/4.0/
 * 
 *******************************************************************************/
package e3.chapter2;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

/**
 * Represents a deck of playing cards. In this version, the cards in the 
 * deck are stored in a list and the list of cards in the deck can 
 * be obtained by client code using an immutable wrapper object.
 */
public class Deck {
	
	private List<Card> aCards = new ArrayList<>();
	
	/**
	 * Creates a new deck of 52 cards, shuffled.
	 */
	public Deck() {
		shuffle();
	}
	
	/**
	 * Reinitializes the deck with all 52 cards, and shuffles them.
	 */
	public void shuffle() {
		aCards.clear();
		for (Suit suit : Suit.values()) {
            for (Rank rank : Rank.values()) {
                aCards.add( new Card(rank, suit));
            }
		}
		Collections.shuffle(aCards);
	}
	
	/**
	 * Places pCard on top of the deck.
	 * 
	 * @param pCard The card to place on top of the deck.
	 * @pre pCard !=null
	 */
	public void push(Card pCard) {
		assert pCard != null;
		aCards.add(pCard);
	}
	
	/**
	 * Draws a card from the deck: removes the card from the top of the deck and
	 * returns it.
	 * 
	 * @return The card drawn.
	 * @pre !isEmpty()
	 */
	public Card draw() {
		assert !isEmpty();
		return aCards.removeLast();
	}
	
	/**
	 * @return True if and only if there are no cards in the deck.
	 */
	public boolean isEmpty() {
		return aCards.isEmpty();
	}
	
	/**
	 * @return An unmodifiable list of all the cards in the deck.
	 */
	public List<Card> cards() {
		return Collections.unmodifiableList(aCards);
	}
}