AjaxEnablingBotServlet.java

package org.aitools.programd.server.servlet;

import java.io.IOException;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.aitools.programd.server.BotAccess;
import org.aitools.util.runtime.Errors;

/**
 * Puts a Bot object into the session context (if it isn't there already) so that the user can conduct a conversation
 * with the bot.
 * 
 * @author <a href="mailto:noel@aitools.org">Noel Bush</a>
 */
public class AjaxEnablingBotServlet extends JSPOrientedBotServlet {

  /**
   * 
   */
  private static final long serialVersionUID = 1L;

  /**
   * Just passes to {@link #setupBot}.
   * 
   * @throws ServletException
   * @see javax.servlet.http.HttpServlet#doGet(javax.servlet.http.HttpServletRequest,
   *      javax.servlet.http.HttpServletResponse)
   */
  @Override
  protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
    this.setupBot(req, resp);
  }

  /**
   * Just passes to {@link #setupBot}.
   * 
   * @throws ServletException
   * @see javax.servlet.http.HttpServlet#doPost(javax.servlet.http.HttpServletRequest,
   *      javax.servlet.http.HttpServletResponse)
   */
  @Override
  protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
    this.setupBot(req, resp);
  }

  /**
   * Creates a {@link org.aitools.programd.Bot Bot} object if necessary, puts it in a session attribute, and forwards to
   * a JSP page.
   * 
   * @param req the request
   * @param resp the response
   * @throws ServletException
   */
  @Override
  protected void setupBot(HttpServletRequest req, HttpServletResponse resp) throws ServletException {
    try {
      super.setupBot(req, resp);
    }
    catch (ServletException e) {
      req.setAttribute("error", Errors.describe(e));
      try {
        JSPOrientedBotServlet.forward(this.errorPage, req, resp);
      }
      catch (IOException ee) {
        throw new ServletException(ee);
      }
      return;
    }

    // See if there is already a bot access object in the session.
    Object botAccessObject = this.session.getAttribute("bot");

    // If it's null, or if it is a bot but there's a bot id specified that doesn't match it, replace it.
    if (botAccessObject == null
        || !(botAccessObject instanceof BotAccess && ((BotAccess) botAccessObject).getBotId().equals(this.botid))) {
      BotAccess botAccess = new BotAccess(this.core, this.botid, this.userid);
      this.session.setAttribute("bot", botAccess);
    }
    else {
      this.bot = ((BotAccess) botAccessObject).getBot();
    }

    String botPage = this.bot.getServletPage();
    if (botPage == null || botPage.length() == 0) {
      botPage = this.defaultBotServletPage;
    }
    try {
      JSPOrientedBotServlet.forward(botPage, req, resp);
    }
    catch (IOException e) {
      throw new ServletException(e);
    }
  }
}