Append methods

Post icon Posted 14 February 2009 - 08:28 AM

I wish to add/remove data from the stock and save the appropriate state using the append method.
How would i apply the append method to the Section highlighted (This Section).
Help would truly appreciated.

 import java.util.*;
public class StockData {

	private static class Item {
		Item(String n, double p, int q) {
			name = n;
			price = p;
			quantity = q;
		}

		// get methods
		public String getName() { return name; }
		public double getPrice() { return price; }
		public int getQuantity() { return quantity; }

		// instance variables 
		private String name;
		private double price;
		private int quantity;
	}


	private static Map<String, Item> stock = new HashMap<String, Item>();

	static {
		// if you want to have extra stock items, put them in here
		// use the same style - keys should be 7 digit Strings
		stock.put("0000000", new Item("Bath towel", 5.50, 10));
		stock.put("1111111", new Item("Plebney light", 20.00, 5));
		stock.put("2222222", new Item("Gorilla suit", 30.00, 7));
		stock.put("3333333", new Item("Whizz games console", 50.00, 8));
		stock.put("4444444", new Item("Oven", 200.00, 4));
	}

	public static String getName(String key) {
		Item item = stock.get(key);
		if (item == null) return null; // null means no such item
		else return item.getName();
	}

	public static double getPrice(String key) {
		Item item = stock.get(key);
		if (item == null) return -1.0; // negative price means no such item
		else return item.getPrice();
	}

	public static int getQuantity(String key) {
		Item item = stock.get(key);
		if (item == null) return -1; // negative quantity means no such item
		else return item.getQuantity();
	}
//This section  :^: 
	// update stock levels
	// extra is +ve if adding stock
	// extra is -ve if selling stock
	public static void update(String key, int extra) {//was int extra
		Item item = stock.get(key);
		if (item != null) item.quantity += extra;//was int extra
//This Section :^: 

	}

	public static void close() {
		// Does nothing for this static version.
		// Write a statement to close the database when you are using one
	}
}

Thank u