NextUnreadServlet.java

package com.commafeed.frontend.servlet;

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

import javax.inject.Inject;
import javax.inject.Singleton;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang3.StringUtils;
import org.hibernate.SessionFactory;

import com.commafeed.CommaFeedConfiguration;
import com.commafeed.backend.dao.FeedCategoryDAO;
import com.commafeed.backend.dao.FeedEntryStatusDAO;
import com.commafeed.backend.dao.FeedSubscriptionDAO;
import com.commafeed.backend.dao.UnitOfWork;
import com.commafeed.backend.model.FeedCategory;
import com.commafeed.backend.model.FeedEntryStatus;
import com.commafeed.backend.model.FeedSubscription;
import com.commafeed.backend.model.User;
import com.commafeed.backend.model.UserSettings.ReadingOrder;
import com.commafeed.backend.service.UserService;
import com.commafeed.frontend.resource.CategoryREST;
import com.commafeed.frontend.session.SessionHelper;
import com.google.common.collect.Iterables;

import lombok.RequiredArgsConstructor;

@SuppressWarnings("serial")
@RequiredArgsConstructor(onConstructor = @__({ @Inject }) )
@Singleton
public class NextUnreadServlet extends HttpServlet {

	private static final String PARAM_CATEGORYID = "category";
	private static final String PARAM_READINGORDER = "order";

	private final SessionFactory sessionFactory;
	private final FeedSubscriptionDAO feedSubscriptionDAO;
	private final FeedEntryStatusDAO feedEntryStatusDAO;
	private final FeedCategoryDAO feedCategoryDAO;
	private final UserService userService;
	private final CommaFeedConfiguration config;

	@Override
	protected void doGet(final HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
		final String categoryId = req.getParameter(PARAM_CATEGORYID);
		String orderParam = req.getParameter(PARAM_READINGORDER);

		SessionHelper sessionHelper = new SessionHelper(req);
		Optional<User> user = sessionHelper.getLoggedInUser();
		if (user.isPresent()) {
			UnitOfWork.run(sessionFactory, () -> userService.performPostLoginActivities(user.get()));
		}
		if (!user.isPresent()) {
			resp.sendRedirect(resp.encodeRedirectURL(config.getApplicationSettings().getPublicUrl()));
			return;
		}

		final ReadingOrder order = (StringUtils.equals(orderParam, "asc") ?
										ReadingOrder.asc :
										(
										StringUtils.equals(orderParam, "desc") ?
											ReadingOrder.desc :
											(
											StringUtils.equals(orderParam, "abc") ?
												ReadingOrder.abc :
												(ReadingOrder.zyx)
											)
										)
									);

		FeedEntryStatus status = UnitOfWork.call(sessionFactory, () -> {
			FeedEntryStatus s = null;
			if (StringUtils.isBlank(categoryId) || CategoryREST.ALL.equals(categoryId)) {
				List<FeedSubscription> subs = feedSubscriptionDAO.findAll(user.get());
				List<FeedEntryStatus> statuses = feedEntryStatusDAO.findBySubscriptions(user.get(), subs, true, null, null, 0, 1, order,
						true, false, null);
				s = Iterables.getFirst(statuses, null);
			} else {
				FeedCategory category = feedCategoryDAO.findById(user.get(), Long.valueOf(categoryId));
				if (category != null) {
					List<FeedCategory> children = feedCategoryDAO.findAllChildrenCategories(user.get(), category);
					List<FeedSubscription> subscriptions = feedSubscriptionDAO.findByCategories(user.get(), children);
					List<FeedEntryStatus> statuses = feedEntryStatusDAO.findBySubscriptions(user.get(), subscriptions, true, null, null, 0,
							1, order, true, false, null);
					s = Iterables.getFirst(statuses, null);
				}
			}
			if (s != null) {
				s.setRead(true);
				feedEntryStatusDAO.saveOrUpdate(s);
			}
			return s;
		});

		if (status == null) {
			resp.sendRedirect(resp.encodeRedirectURL(config.getApplicationSettings().getPublicUrl()));
		} else {
			String url = status.getEntry().getUrl();
			resp.sendRedirect(resp.encodeRedirectURL(url));
		}
	}
}