In Java without arrays,

Create a shopping list program. Write a class called ShoppingList which allows users to add or remove items from a String that you are treating as a shopping list. No arrays allowed in this program. The class ShoppingList has the following methods:

ShoppingList() - a no-args constructor that creates a new, empty ShoppingList

ShoppingList(String items) - a one arg constructor that creates a ShoppingList of the given String (items separated by commas)

String toString() - returns the current contents of the shopping list, separated by commas

void addItem(String anItem) - adds a new item to the end of the shopping list if it's not already on the list

void removeItem(String anItem) - removes an item from the shopping list (if it is on the list)

Current Code:

public class ShoppingList {

String list = "";

public ShoppingList() {

this.list += "";

}

public ShoppingList(String items) {

this.list += list;

}

public String toString() {

String temp = "";

if(this.list.contains(",")) {

temp = list.substring(0,this.list.lastIndexOf(","));

}

return temp;

}

public void addItem(String anItem) {

if(!this.list.contains(anItem)) {

this.list += anItem+",";

}

}

public void removeItem(String anItem) {

this.list.replace(anItem + ","," ");

}

Currently only works for first test but having trouble placing commas in toString, will someone help with that?