shoppingcartitem.java

beginJsp2.0外文书籍源代码

package com.wrox.shop;

/**
 * Models a shopping cart item consisting of a Book and a quantity.
 */
public class ShoppingCartItem {
    
    private final Book book;
    private int quantity;

    /** Creates a new shopping cart item
     * @param book The book to create the item for.
     */    
    public ShoppingCartItem(Book book) {
        super();
        this.book = book;
        this.quantity = 1;
    }
    
    /**
     * Retrieves the Book.
     * @return The Book.
     */    
    public Book getBook() {
        return book;
    }
    
    /**
     * Retrieves the quantity for the book.
     * @return The quantity.
     */    
    public int getQuantity() {
        return quantity;
    }
    
    /**
     * Sets the quantity for the book.
     * @param quantity The desired quantity.
     */    
    public void setQuantity(int quantity) {
        this.quantity = quantity;
    }
    
    /** Two items are equal if they both have the same book.
     * @param obj The object to compare to.
     * @return <code>true</code> if the object is a ShoppingCartItem
     * and contains the same book
     */    
    public boolean equals(Object obj) {
        return obj instanceof ShoppingCartItem &&
               equals((ShoppingCartItem)obj);
    }

    /** Two items are equal if they both have the same book.
     * @param that The ShoppingCartItem to compare to.
     * @return <code>true</code> if the object is a ShoppingCartItem
     * and contains the same book
     */    
    public boolean equals(ShoppingCartItem that) {
        return this.book == that.book;
    }
    
    /** Overridden to be consistent with equals().
     * @return A hash code for this object.
     */    
    public int hashCode() {
        return book.hashCode();
    }
}