package com.versefeed.crud;

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

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.swing.text.Utilities;

import com.google.appengine.api.datastore.DatastoreService;
import com.google.appengine.api.datastore.DatastoreServiceFactory;
import com.google.appengine.api.datastore.Entity;
import com.google.appengine.api.datastore.Text;

/*
 i declare and instantiate class variable "private CrudDsUtilities utilities" in the servlet constructor, but it's not seen in other functions of the servlet. it is throwing java.lang.NullPointerException

*/

public class CrudServlet extends HttpServlet {

    private DatastoreService ds;
    private String entityKind;
    private CrudDsUtilities utilities;

    private void CrudServlet() {
        ds = DatastoreServiceFactory.getDatastoreService();
        utilities = new CrudDsUtilities();

    }

    public void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws IOException {

        String operation = req.getParameter("op");
        String verseTitle, verseRef, verseBody;
        long verseId;
        switch (operation) {

        case "view":
            verseId = Long.getLong(req.getParameter("verseId"));
            entityKind = req.getParameter("entityKind");

            break;

        case "viewverses":
            entityKind = req.getParameter("entitykind");
            System.out.println("entityKind: "+ entityKind);
            this.viewVerses(req, resp);
            break;

        default:
            break;
        }

    }

    public void viewVerse(long verseId) {

    }

    public void viewVerses(HttpServletRequest req, HttpServletResponse resp) {

//throwing java.lang.NullPointerException on this line! it doesn't see "utilities" as already instantiated in the constructor.
        List<Entity> verses = utilities.getEntitiesAsList(entityKind);

        try {
            // Set the attribute and Forward to hello.jsp
            req.setAttribute ("verses", verses); // to save your temporary calculations.
            req.getRequestDispatcher("/verses.jsp").forward(req, resp);
        } catch (Exception ex) {
            ex.printStackTrace ();
        }

    }

}// close class

//traceback

java.lang.NullPointerException
    at com.versefeed.crud.CrudServlet.viewVerses(CrudServlet.java:109)
    at com.versefeed.crud.CrudServlet.doGet(CrudServlet.java:68)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:617)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:717)