io.spring.springoverflow.controller.PostController.java Source code

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Here is the source code for io.spring.springoverflow.controller.PostController.java

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/*
 * Copyright 2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.spring.springoverflow.controller;

import io.spring.springoverflow.domain.PageWrapper;
import io.spring.springoverflow.domain.Post;
import io.spring.springoverflow.domain.PostRepository;
import io.spring.springoverflow.domain.Tag;
import io.spring.springoverflow.domain.User;
import io.spring.springoverflow.domain.UserRepository;
import org.apache.mahout.cf.taste.recommender.ItemBasedRecommender;
import org.apache.mahout.cf.taste.recommender.RecommendedItem;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.PageRequest;
import org.springframework.data.domain.Pageable;
import org.springframework.security.core.context.SecurityContextHolder;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;

import java.util.ArrayList;
import java.util.Collections;
import java.util.Date;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

/**
 * @author Michael Minella
 */
@Controller
public class PostController {

    @Autowired
    ItemBasedRecommender recommender;

    @Autowired
    PostRepository postRepository;

    @Autowired
    UserRepository userRepository;

    @RequestMapping("/")
    public String list(Pageable pageable, Model model) {
        Page<Post> curPage = postRepository.findAllByPostTypeIdOrderByCreationDateDesc(1, pageable);

        PageWrapper<Post> page = new PageWrapper<>(curPage, "/");
        model.addAttribute("page", page);
        return "post/index";
    }

    @RequestMapping("/post/{id}")
    public String show(@PathVariable long id, Model model) {
        Post curPost = postRepository.findOne(id);

        curPost.setViewCount(curPost.getViewCount() + 1);
        postRepository.save(curPost);

        model.addAttribute("post", curPost);
        if (!model.containsAttribute("recommendations")) {
            model.addAttribute("recommendations", new ArrayList<Post>());
        }

        return "post/show";
    }

    @RequestMapping(value = "/post/save", method = RequestMethod.POST)
    public String save(@RequestParam(value = "postId", required = true) long parentPostId,
            @RequestParam(value = "body", required = true) String body, Model model) throws Exception {
        String username = SecurityContextHolder.getContext().getAuthentication().getName();

        User currentUser = userRepository.findByDisplayName(username);
        long userId = currentUser.getId();

        Post post = new Post();
        post.setBody(body);
        post.setCreationDate(new Date());
        post.setOwnerUser(currentUser);
        post.setPostTypeId(2);

        Post parentPost = postRepository.findOne(parentPostId);
        parentPost.getAnswers().add(post);
        parentPost.setAnswerCount(parentPost.getAnswerCount() + 1);

        postRepository.save(parentPost);

        List<RecommendedItem> items;
        List<Post> matchingPosts = new ArrayList<>();

        // Recommendations by Question's Tags
        matchingPosts.addAll(recommendPostsByItemsTags(parentPost));

        // Recommendations by User's History
        //      matchingPosts.addAll(recommendPostsByUsers(currentUser));

        // Recommendations By Both
        //      matchingPosts.addAll(recommendPostsByUsers(currentUser));
        //      matchingPosts.addAll(recommendPostsByItemsTags(parentPost));

        if (matchingPosts.size() < 3) {
            items = recommendItems(parentPost.getTags());

            for (RecommendedItem item : items) {
                List<Post> posts = postRepository.findByTagId(item.getItemID(), new PageRequest(0, 3));

                matchingPosts.addAll(posts);
            }
        }

        Set<Post> recommendedPosts = new HashSet<>(3);

        if (matchingPosts.size() > 3) {
            Collections.shuffle(matchingPosts);
            recommendedPosts.addAll(matchingPosts.subList(0, 3));
        } else {
            recommendedPosts.addAll(matchingPosts);
        }

        model.addAttribute("post", parentPost);
        model.addAttribute("recommendations", recommendedPosts);

        return "post/show";
    }

    private List<Post> recommendPostsByItemsTags(Post parentPost) throws Exception {
        List<RecommendedItem> items = new ArrayList<>();

        for (Tag tag : parentPost.getTags()) {
            items.addAll(recommender.mostSimilarItems(tag.getId(), 10));
        }

        List<Post> matchingPosts = new ArrayList<>();

        for (RecommendedItem item : items) {
            List<Post> posts = postRepository.findByTagId(item.getItemID(), new PageRequest(0, 3));

            matchingPosts.addAll(posts);
        }

        return matchingPosts;
    }

    private List<Post> recommendPostsByUsers(User user) throws Exception {
        List<RecommendedItem> items = recommender.recommend(user.getId(), 10);
        List<Post> matchingPosts = new ArrayList<>();

        for (RecommendedItem item : items) {
            List<Post> posts = postRepository.findByTagId(item.getItemID(), new PageRequest(0, 3));

            matchingPosts.addAll(posts);
        }

        return matchingPosts;
    }

    private List<RecommendedItem> recommendItems(Set<Tag> tags) throws Exception {
        List<RecommendedItem> items = new ArrayList<>();

        for (Tag tag : tags) {
            items.addAll(recommender.mostSimilarItems(tag.getId(), 10));
        }

        return items;
    }
}