war/src/main/java/pnews/servlet/ArticleProvider.java

   1 package pnews.servlet;
   2
   3 import java.io.IOException;
   4 import java.net.MalformedURLException;
   5 import java.net.URL;
   6 import java.util.ArrayList;
   7 import java.util.Collections;
   8 import java.util.Comparator;
   9 import java.util.Date;
  10 import java.util.HashMap;
  11 import java.util.List;
  12 import java.util.Map;
  13 import java.util.concurrent.Executors;
  14 import java.util.concurrent.ScheduledExecutorService;
  15 import java.util.concurrent.TimeUnit;
  16 import java.util.logging.Level;
  17 import java.util.logging.Logger;
  18
  19 import org.jsoup.Jsoup;
  20
  21 import com.rometools.rome.feed.synd.SyndEnclosure;
  22 import com.rometools.rome.feed.synd.SyndEntry;
  23 import com.rometools.rome.feed.synd.SyndFeed;
  24 import com.rometools.rome.io.FeedException;
  25 import com.rometools.rome.io.SyndFeedInput;
  26 import com.rometools.rome.io.XmlReader;
  27
  28 import pnews.Article;
  29 import pnews.Category;
  30 import pnews.Feed;
  31
  32 public class ArticleProvider {
  33         private static final Logger LOG = Logger.getLogger(ArticleProvider.class.getName());
  34         private final Map<Category, List<Article>> articlesByCategory = new HashMap<>();
  35         private final ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(2);
  36         private final Config config;
  37
  38         public ArticleProvider(Config config) {
  39                 this.config = config;
  40                 for (Category cat: config.getCategories())
  41                         scheduler.scheduleAtFixedRate(new Refresher(cat), 2, 600, TimeUnit.SECONDS);
  42         }
  43
  44         private static SyndFeed getSyndFeed(String u) throws IllegalArgumentException, FeedException, MalformedURLException, IOException {
  45                 XmlReader r;
  46
  47                 r = new XmlReader(new URL(u));
  48
  49                 return new SyndFeedInput().build(r);
  50         }
  51
  52         private List<Article> getArticlesForUpdate(Category cat) {
  53                 List<Article> result;
  54
  55                 synchronized (articlesByCategory) {
  56                         result = articlesByCategory.get(cat);
  57                         if (result == null) {
  58                                 result = new ArrayList<>();
  59                                 articlesByCategory.put(cat, result);
  60                         }
  61                         return result;
  62                 }
  63         }
  64
  65         private boolean exists(String articleLink, List<Article> articles) {
  66                 synchronized (articles) {
  67                         for (Article a: articles)
  68                                 if (a.link.equals(articleLink))
  69                                         return true;
  70                 }
  71                 return false;
  72         }
  73
  74         private static Article toArticle(String link, SyndEntry entry, SyndFeed feed) {
  75                 String desc, title, thumbnail, feedTitle, str;
  76                 Date date;
  77
  78                 feedTitle = feed.getTitle();
  79                 if (feedTitle != null) {
  80                         feedTitle = feedTitle.trim();
  81                 }
  82
  83                 thumbnail = null;
  84                 for (SyndEnclosure e: entry.getEnclosures()) {
  85                         if (e.getType().startsWith("image/"))
  86                                 thumbnail = e.getUrl();
  87                         break;
  88                 }
  89
  90                 if (thumbnail == null && feed.getImage() != null)
  91                         thumbnail = feed.getImage().getUrl();
  92
  93
  94                 title = entry.getTitle().trim();
  95
  96                 if (entry.getDescription() != null) {
  97                         str = entry.getDescription().getValue();
  98                         desc = Jsoup.parse(str).text();
  99                 } else {
 100                         desc = null;
 101                         LOG.severe("No description for " + feedTitle + " - " + title);
 102                 }
 103
 104                 date = entry.getPublishedDate();
 105                 if (date == null)
 106                         date = entry.getUpdatedDate();
 107                 if (date == null)
 108                         LOG.severe("The article " + feedTitle + " - " + title + " does not have a date");
 109
 110                 return new Article(link, title, desc, thumbnail, date, feedTitle);
 111         }
 112
 113         private void addArticles(Category cat, SyndFeed feed) {
 114                 String feedTitle;
 115                 List<Article> articles;
 116                 Article a;
 117
 118                 feedTitle = feed.getTitle().trim();
 119
 120                 LOG.info("addArticles " + cat.getLabel() + " " + feedTitle + " number of articles: " + feed.getEntries().size());
 121
 122                 for (SyndEntry entry: feed.getEntries()) {
 123                         String link = entry.getLink().trim();
 124                         articles = getArticlesForUpdate(cat);
 125                         if (exists(link, articles)) {
 126                                 LOG.fine("addArticles " + link + " is already present");
 127                                 continue ;
 128                         }
 129
 130                         a = ArticleStore.singleton.getArticle(link, ()->toArticle(link, entry, feed));
 131
 132                         synchronized (articles) {
 133                                 articles.add(a);
 134
 135                                 Collections.sort(articles, new Comparator<Article>() {
 136                                         @Override
 137                                         public int compare(Article o1, Article o2) {
 138                                                 if (o1.publicationDate == o2.publicationDate)
 139                                                         return 0;
 140                                                 if (o1.publicationDate == null)
 141                                                         return 1;
 142                                                 if (o2.publicationDate == null)
 143                                                         return -1;
 144                                                 return o2.publicationDate.compareTo(o1.publicationDate);
 145                                         }
 146                                 });
 147                         }
 148                 }
 149
 150                 LOG.info("addArticles done " + cat.getLabel());
 151         }
 152
 153         private void retrieveArticles(Category cat) throws IllegalArgumentException, MalformedURLException, FeedException, IOException {
 154                 List<Feed> feeds;
 155
 156                 feeds = config.getFeedsByCategory().get(cat);
 157
 158                 if (feeds != null)
 159                         for (Feed f: feeds)
 160                                 try {
 161                                         addArticles(cat, getSyndFeed(f.getURL()));
 162                                 } catch (Throwable e) {
 163                                         LOG.log(Level.SEVERE,
 164                                                 "retrieveArticles failure " + cat.getLabel() + " " + f.toString(),
 165                                                 e);
 166                                 }
 167                 else
 168                         LOG.severe("No feed for category " + cat);
 169         }
 170
 171         /**
 172          * Returns a copy.
 173          */
 174         public List<Article> getArticles(Category cat)
 175                         throws IllegalArgumentException, MalformedURLException, FeedException, IOException {
 176                 List<Article> articles;
 177
 178                 synchronized (articlesByCategory) {
 179                         articles = getArticlesForUpdate(cat);
 180                 }
 181
 182                 synchronized (articles) {
 183                         return new ArrayList<>(articles);
 184                 }
 185         }
 186
 187         private class Refresher implements Runnable {
 188                 private final Category category;
 189
 190                 public Refresher(Category category) {
 191                         this.category = category;
 192                 }
 193
 194                 @Override
 195                 public void run() {
 196                         LOG.info("refresher "+ category.getLabel());
 197
 198                         try {
 199                                 retrieveArticles(category);
 200                         } catch (IllegalArgumentException | FeedException | IOException e) {
 201                                 LOG.log(Level.SEVERE, "refresher failure", e);
 202                         }
 203
 204                         LOG.info("refresher "+ category.getLabel() + " done");
 205                 }
 206         }
 207 }