ADDITEM

package homework;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


import homework.Item;
@WebServlet("/AddItem")
public class AddItem extends HttpServlet {
	private static final long serialVersionUID = 1L;


    public AddItem() {
        super();
    }
    public void init(ServletConfig config) throws ServletException {
        super.init(config);

        ArrayList<String> error = new ArrayList<String>();
        getServletContext().setAttribute("error", error);

    }

	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		response.setContentType( "text/html" );
        PrintWriter out = response.getWriter();
		out.println("<!DOCTYPE html>");
		out.println("<html>");
		out.println("<head>");
		out.println("<title>Add Item</title>");
		out.println("</head>");
		out.println("<body>");
		out.println("<form action=\"AddItem\" method=\"post\">");

		List<String> error = (List<String>) getServletContext().getAttribute("error");

		out.println("Name: <input type=\"text\" name=\"name\"  /> <br /> ");
		if(error.contains("Invalid name"))
		{
			out.println("<p>Invalid name</p>");
		}
		out.println("Description: <input type=\"textarea\" name=\"description\"  /> <br /> ");
		if(error.contains("Invalid desc"))
		{
			out.println("<p>Invalid Description</p>");
		}
		out.println("Quantity: <input type=\"text\" name=\"quantity\"  />  <br />");
		out.println("Price: <input type=\"text\" name=\"price\"  />  <br />");

		out.println("<input type=\"submit\" value=\"Add\"><br/><br/>");

		out.println("</form>");

		out.println("</body>");
		out.println("</html>");
	}

	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		boolean er=true;
		String name= request.getParameter("name");
		String description= request.getParameter("description");
		int quantity= Integer.parseInt(request.getParameter("quantity"));
		Double price= Double.parseDouble(request.getParameter("price"));
		@SuppressWarnings("unchecked")
		List<String> error = (List<String>) getServletContext().getAttribute("error");

		if(name==null || name.trim().length()==0)
		{
			error.add("Invalid name");
			er=true;
		}
		else if(description==null || description.trim().length()==0)
		{
			error.add("Invalid desc");
			er=true;
		}
		else if(request.getParameter("quantity")==null || request.getParameter("quantity").trim().length()==0)
		{
			error.add("Invalid qunaity");
			er=true;
		}
//		try
//		{
//			int i = Integer.parseInt(request.getParameter("quantity"));
//		}
//		catch(NumberFormatException nfe)
//		{
//			error.add("Invalid q");
//			er=true;
//		}


		else
		{
			er=false;
		}

		if(er==false)
		{
		@SuppressWarnings("unchecked")
		List<Item> inventory = (List<Item>) getServletContext().getAttribute("inventory");
		inventory.add(new Item(name, description, quantity, price));
		response.sendRedirect( "Inventory" );
		}
		else if(er==true)
		{
			doGet(request, response);
			return;

		}
	}

}