huge refactor

hypervisor now don't rely on collections but only on the SQLite database for saving what post it has computed. It saves each post after each post, and marks it as shared before sharing it so if something bad happens, then it won't crash on it again. RAM usage has been improved too. After 8hrs running, it used more than 1GB. Now it barely uses more than 50MB.
Added a try catch for null pointer exception so it won't crash if a part of the JSON is missing. It'll just continue and don't compute this reddit post.

twitter_techsupportgore_bot/src/TwitterTechSupportGoreBot/Hypervisor.java

@@ -61,16 +61,6 @@ public class Hypervisor {
      */
     private final String tableName;
     
-    /**
-     * All the reddit posts parsed.
-     */
-    private final HashMap<String, RedditPost> redditPosts;
-
-    /**
-     * All the already shared posts, so there are no boule shares.
-     */
-    private final HashMap<String, RedditPost> alreadySharedPosts;
-
     /**
      * Delay between two scans, in seconds.
      */
@@ -120,13 +110,11 @@ public class Hypervisor {
         this.delay = Integer.valueOf(reader.getProperties("delay"));
         this.sqliteDatabase = reader.getProperties("sqlite_db_name");
         this.socialMedias = new ArrayList<>();
-        this.redditPosts = new HashMap<>();
         this.workingDirectory = reader.getProperties("working_directory");
         setupTheBotDirectory();
         this.connexion = DriverManager.getConnection("jdbc:sqlite:"
                 + this.workingDirectory + File.separator + this.sqliteDatabase);
         this.myRedditExtractor = new RedditExtractor(subreddit);
-        this.alreadySharedPosts = new HashMap<>();
         if ("Y".equals(reader.getProperties("clear_database"))) {
             clearDatabase();
         }
@@ -172,7 +160,6 @@ public class Hypervisor {
             for (RedditPost post : myRedditExtractor.getRedditPosts()) {
                 computeRedditPost(post);
             }
-            save();
             System.out.println(
                     "[*] Hypervisor is waiting for " + this.delay + " seconds.");
             Thread.sleep(this.delay * 1000);
@@ -186,70 +173,14 @@ public class Hypervisor {
      * @throws SQLException
      */
     private void load() throws ClassNotFoundException, SQLException {
-        System.out.println("[*] Loading the Reddit posts from database.");
         createTable();
         PreparedStatement recherche = this.connexion.prepareStatement(
-                "SELECT * FROM " + this.tableName + ";");
+                "SELECT COUNT(id) AS cpt FROM " + this.tableName + ";");
         try (ResultSet res = recherche.executeQuery()) {
-            while (res.next()) {
+            res.next();
-                RedditPost post
+            System.out.println("[*] " + res.getInt("cpt") + " posts in database.");
-                        = "image".equals(res.getString("postType"))
-                        ? new RedditPostImage(res.getString("postId"),
-                                res.getString("title"),
-                                res.getBoolean("quarantine"),
-                                res.getDouble("score"),
-                                res.getString("postHint"),
-                                res.getBoolean("crosspostable"),
-                                res.getBoolean("over18"),
-                                res.getString("author"),
-                                res.getString("permalink"),
-                                res.getBoolean("spoiler"),
-                                res.getString("url"))
-                        : "link".equals(res.getString("postType"))
-                        ? new RedditPostLink(res.getString("postId"),
-                                res.getString("title"),
-                                res.getBoolean("quarantine"),
-                                res.getDouble("score"),
-                                res.getString("postHint"),
-                                res.getBoolean("crosspostable"),
-                                res.getBoolean("over18"),
-                                res.getString("author"),
-                                res.getString("permalink"),
-                                res.getBoolean("spoiler"),
-                                res.getString("url"))
-                        : "video".equals(res.getString("postType"))
-                        ? new RedditPostVideo(res.getString("postId"),
-                                res.getString("title"),
-                                res.getBoolean("quarantine"),
-                                res.getDouble("score"),
-                                res.getString("postHint"),
-                                res.getBoolean("crosspostable"),
-                                res.getBoolean("over18"),
-                                res.getString("author"),
-                                res.getString("permalink"),
-                                res.getBoolean("spoiler"),
-                                res.getString("url"))
-                        : new RedditPostText(res.getString("postId"),
-                                res.getString("title"),
-                                res.getBoolean("quarantine"),
-                                res.getDouble("score"),
-                                res.getString("postHint"),
-                                res.getBoolean("crosspostable"),
-                                res.getBoolean("over18"),
-                                res.getString("author"),
-                                res.getString("permalink"),
-                                res.getBoolean("spoiler"),
-                                res.getString("url"));
-                this.redditPosts.put(post.getPostId(), post);
-                if (res.getBoolean("shared")) {
-                    this.alreadySharedPosts.put(post.getPostId(), post);
         }
     }
-        }
-        System.out.println("[*] Loading done. "
-                + this.redditPosts.size() + " posts loaded. "
-                + this.alreadySharedPosts.size() + " posts already shared.");
-    }
 
     /**
      * Clear the database by dropping it.
@@ -268,16 +199,17 @@ public class Hypervisor {
     }
 
     /**
-     * Save all the reddit posts to the database.
+     * Add a given reddit post to the database.
+     * 
+     * @param current a given reddit post to add to the database
      *
      * @throws ClassNotFoundException
      * @throws SQLException
      */
-    private void save() throws ClassNotFoundException, SQLException {
+    private void addRedditPostToDatabase(RedditPost current)
+            throws ClassNotFoundException, SQLException {
         createTable();
-        for (String postId : this.redditPosts.keySet()) {
+            if (!isInDatabase(current.getPostId())) {
-            RedditPost current = this.redditPosts.get(postId);
-            if (!isInDatabase(postId)) {
                 PreparedStatement ajout = this.connexion.prepareStatement(
                         "INSERT INTO " + this.tableName
                         + "("
@@ -314,10 +246,9 @@ public class Hypervisor {
                 ajout.setString(10, current.getPermalink());
                 ajout.setBoolean(11, current.isSpoiler());
                 ajout.setString(12, current.getUrl());
-                ajout.setBoolean(13, this.alreadySharedPosts
+                ajout.setBoolean(13, false);
-                        .containsKey(current.getPostId()));
                 ajout.execute();
-            }
+            
         }
     }
 
@@ -340,6 +271,28 @@ public class Hypervisor {
         }
     }
 
+    /**
+     * Check if a post is marked as shared in database.
+     *
+     * @param postId the post id
+     * @return if the post is shared in the database
+     *
+     * @throws SQLException
+     * @throws ClassNotFoundException
+     */
+    private boolean isShared(String postId)
+            throws SQLException, ClassNotFoundException {
+        PreparedStatement recherche = this.connexion.prepareStatement(
+                "SELECT shared FROM " + this.tableName + " "
+                + "WHERE postId = '" + postId + "'");
+        try (ResultSet resultats = recherche.executeQuery()) {
+            if (resultats.next()) {
+                return resultats.getBoolean("shared");
+            }
+            return false;
+        }
+    }
+
     /**
      * Set a post as shared onsocial networks.
      *
@@ -348,22 +301,18 @@ public class Hypervisor {
      * @throws SQLException
      * @throws ClassNotFoundException
      */
-    private void setPostAsShared(String postId)
+    private void setPostAsShared(RedditPost r)
             throws SQLException, ClassNotFoundException {
         System.out.println("[+] Post \""
-                + this.redditPosts.get(postId).getTitle()
+                + r.getTitle()
-                + "\" has been shared successfully.");
+                + "\" is about to be shared.");
-        this.alreadySharedPosts.put(postId, this.redditPosts.get(postId));
-        if (isInDatabase(postId)) {
         PreparedStatement update = this.connexion.prepareStatement(
                 "UPDATE " + this.tableName + " "
                 + "SET shared=? "
-                    + "WHERE postId = '" + postId + "';"
+                + "WHERE postId = '" + r.getPostId() + "';");
-            );
         update.setBoolean(1, true);
         update.execute();
     }
-    }
 
     /**
      * Create our working table if it doesn't exists yet.
@@ -404,13 +353,13 @@ public class Hypervisor {
      */
     private void computeRedditPost(RedditPost r)
             throws SQLException, ClassNotFoundException {
-        if (!this.alreadySharedPosts.containsKey(r.getPostId())
+        if (!isShared(r.getPostId()) && !r.isQuarantine()) {
-                && !r.isQuarantine()) {
             System.out.println(
                     "[*] Computing the post \"" + r.getTitle() + "\"");
-            this.redditPosts.put(r.getPostId(), r);
+            addRedditPostToDatabase(r);
             if (r.hasMediaUrl()) {
                 String fileName = saveImage(r.getUrl());
+                setPostAsShared(r);
                 socialMedias.forEach((s) -> {
                     long postRef = s.postImage(
                             formatPost(r.getTitle()), fileName);
@@ -422,8 +371,10 @@ public class Hypervisor {
                     }
                 });
                 deleteFile(fileName);
+                System.out.println("[+] Post \""
+                        + r.getTitle()
+                        + "\" has been shared successfully.");
             }
-            setPostAsShared(r.getPostId());
         }
     }
 

twitter_techsupportgore_bot/src/TwitterTechSupportGoreBot/redditHandler/RedditExtractor.java

@@ -145,6 +145,7 @@ public final class RedditExtractor {
             JsonArray children = new JsonParser().parse(data.get("children")
                     .toString()).getAsJsonArray();
             for (int i = 0; i < children.size(); i++) {
+                try {
                     JsonObject child = new JsonParser().parse(children.get(i)
                             .toString()).getAsJsonObject();
                     JsonObject childData = new JsonParser().parse(child.get("data")
@@ -207,6 +208,11 @@ public final class RedditExtractor {
                                     permalink, spoiler, url));
                         }
                     }
+                } catch (NullPointerException e) {
+                    System.out.println(
+                            "[*] There were a problem while parsing. "
+                            + "Continuing");
+                }
             }
             return set;
         } catch (JsonSyntaxException e) {