public class Comment {
    private final String text;
    private final Font font;
    private final Color fontColor;
    
    private double x;
    private int y;
    
    private final int width;
    private final int height;
    private final int margin = 10;
    
    private final long createdDate = System.nanoTime();
    
    // Constructor, getter/setter, equals, hashCode は省略
}

public class CommentFrame extends JFrame {
    public CommentFrame() {
        // 画面中央に寄せる
        setLocationRelativeTo(null);
        // 画面のデコレーション(閉じるボタンとか)を切らないと透明にならない
        setUndecorated(true);
        
        setBackground(new Color(0,0,0,0));
        getContentPane().setBackground(new Color(0,0,0,0));
		
        setSize(800, 600);
        setResizable(true);
        setVisible(true); //表示！
    }
}

public class CommentPanel extends JPanel {
    // 今あるコメントを保存する
    private List<Comment> commentList = new LinkedList<>();

    public CommentPanel(Color backgroundColor, Color borderColor) {
        // 枠の色を設定
        setBorder(new LineBorder(borderColor));
        setBackground(backgroundColor);

        // コメントの位置は絶対座標で指定したいのでレイアウトは指定しない
        setLayout(null);
    }
}

@Override
public void setBackground(Color bg) {
    if(bg.getAlpha() != 0) {
        super.setBackground(bg);
    } else {
        setOpaque(false); //JFrameは透明のときこうしないとバグる
    }
}

@Override
public void paintComponent(Graphics g) {
    super.paintComponent(g);
    // リストにあるコメントを全部描画する
    for(Comment c : commentList) {
        g.setFont(c.getFont());

        // あとで使います
        // g.setColor(Color.GRAY);
        // paintFontBorder(g, c, 2);

        g.setColor(c.getFontColor());
        int x = c.getX();
        int y = c.getY() + c.getHeight() - c.getMargin();
        g.drawString(c.getText(), x, y);
    }
}

public void paintComments(List<Comment> commentList) {
    this.commentList = commentList;
    repaint(); //paintComponentを呼び出すおまじない
}

private void paintFontBorder(Graphics g, Comment c, int borderSize) {
    for(int i = -borderSize; i <= borderSize; i++) {
        for(int j = -borderSize; j <= borderSize; j++) {
            int x = c.getX() + i;
            int y = c.getY() + j + c.getHeight() - c.getMargin();
            g.drawString(c.getText(), x, y);
        }
    }
}

public class CommentProvider {
    // フレーム本体をメモしておく
    private final CommentFrame SCREEN;

    private final List<Comment> ACTIVE_COMMENTS = 
        Collections.synchronizedList(new LinkedList<>());
    private final Queue<String> COMMENT_STR_QUEUE = 
        new ConcurrentLinkedQueue<>();
    private final Set<Comment> NEW_COMMENTS 
        = Collections.synchronizedSet(new HashSet<>());

    private final TreeSet<Integer> INSERTABLE_Y = new TreeSet<>();

    private final Timer TIMER = new Timer(10, e -> moveComments());

    private final int FONT_HEIGHT;

    public CommentProvider(CommentFrame SCREEN) {
        this.SCREEN = SCREEN;
        this.FONT_HEIGHT = config.FONT_SIZE + 20; //20はマージン分
        
        refreshInsertableY();
    }
    
    // 画面をフォントの高さで割って挿入可能な高さリストをつくる
    public void refreshInsertableY() {
        synchronized(INSERTABLE_Y) {
            for(int i = 0; i + FONT_HEIGHT <= SCREEN.getHeight(); i += FONT_HEIGHT) {
                INSERTABLE_Y.add(i);
            }
        }
    }
}

public void addComment(String comment) {
    System.err.println(comment);
    if(!canInsert()) return;
    COMMENT_STR_QUEUE.add(comment);
}

public synchronized boolean canInsert() {
    return !INSERTABLE_Y.isEmpty();
}

private synchronized int pollOptimalY() {
    Integer ret = INSERTABLE_Y.pollFirst();
    return ret == null ? - FONT_HEIGHT : ret;
}

private synchronized void moveComments() {
    
	// Cのポインタみたいなやつ
    Iterator<Comment> it = ACTIVE_COMMENTS.iterator();

    // 2048は速度調整
    double dx = - (commentSpeed * updateInterval) / 2048.0; 
    
    while(it.hasNext()) {
        Comment cmt = it.next();

        cmt.setDoubleX(cmt.getDoubleX() + dx);

        // コメントが初めて画面に入りきったか
        boolean canInsertOnThisLine = 
            cmt.getDoubleX() + cmt.getWidth() + 10 < SCREEN.getWidth() && NEW_COMMENTS.contains(cmt);
        if(canInsertOnThisLine) {
            synchronized(INSERTABLE_Y){
                INSERTABLE_Y.add(cmt.getY());
            }
            NEW_COMMENTS.remove(cmt);
        }

        boolean inViewerBounds = cmt.getDoubleX() + cmt.getWidth() >= 0;
        if(!inViewerBounds) {
            it.remove();
        }
    }

    // 描画
    SCREEN.getInnerPanel().paintComments(ACTIVE_COMMENTS);

    // 描画できる限りキューのコメントを拾ってくる
    insertCommentsInQueue();
}

private void insertCommentsInQueue() {
    while(canInsert() && !COMMENT_STR_QUEUE.isEmpty()) {
        // 画面の右端にコメントを追加
        Comment newComment = new Comment(COMMENT_STR_QUEUE.poll(), SCREEN.getWidth(), pollOptimalY());
        ACTIVE_COMMENTS.add(newComment);
        NEW_COMMENTS.add(newComment);
    }
}

public class WordStreamReader implements StatusListener {
    private TwitterStream twitterStream;
    private final CommentProvider COMMENT_PROVIDER;

    // TwitterCommentFactoryについてはあとで説明します
    private TwitterCommentFactory commentFactory = new TwitterCommentFactory();

    public WordStreamReader(CommentProvider cp, String filterTextPath) throws IOException {
        COMMENT_PROVIDER = cp;

        // ファイルを読んで行ごとに区切って配列にする
        String[] filterWords =
                Files.readAllLines(Paths.get(filterTextPath))
                .stream()
                .map(String::trim)
                .toArray(String[]::new);
        
		// フィルタに配列を入れる
        FilterQuery filterQuery = new FilterQuery();
        filterQuery.track(filterWords);

        // ストリーミングを開始
        twitterStream = new TwitterStreamFactory().getInstance();
        twitterStream.addListener(this);
        twitterStream.filter(filterQuery);

        // アプリケーション終了時にストリームを閉じるようにする
        Runtime.getRuntime().addShutdownHook(new Thread(() -> {
            twitterStream.shutdown();
        }));
    }
}

@Override
public void onStatus(Status status) {
    String comment = status.getText();
    // RTとリプライを排除
    if(status.isRetweet()) return;
    if(status.getInReplyToUserId() > 0) return;
    COMMENT_PROVIDER.addComment(commentFactory.generate(status));
}

public class TwitterCommentFactory {

    private boolean screenNameVisible = false;
    private boolean nameVisible = false;
    private boolean removeLinks = true;
    private boolean removeHashtags = true;

    public String generate(Status status) {
        String screenName = status.getUser().getScreenName();
        String name       = status.getUser().getName();
        
        // 改行やスペースで分けてハッシュタグやリンクを削除する
        String tweet      =
                Arrays.stream(status.getText().split("[ 　\n]"))
                .filter(e -> !removeLinks || !e.matches("^https://t\\.co/.*"))
                .filter(e -> !removeHashtags || !e.matches("^#.+"))
                .collect(Collectors.joining(" "));
        
        // 4つの形式に対応して表示を加工
        if(screenNameVisible && nameVisible)
            return name + "(@" + screenName + "): " + tweet;
        else if(screenNameVisible)          
            return screenName + ": " + tweet;
        else if(nameVisible)                
            return name + ": " + tweet;
        else                                
            return tweet;
    }
}

public class Main {
    public static void main(String[] args) {
        CommentFrame frame = new CommentFrame(new ScreenConfigs("filePath"));
        CommentStreamReader stream = new CommentStreamReader();
    }
}

class CommentStreamReader implements CommentListner {
    CommentFrame frame;
    CommentStream stream;
    
    public CommentStream(CommentFrame frame) {
        this.frame = frame;
        this.stream = new CommentStream();
        stream.addListener(this);
    }
    
    @Override
    public void onCommentReceived(String comment) {
        frame.getCommentProvider().addComment(comment);
    }
}

class CommentStream {
 	// APIを叩いてストリームに流すやつ
}

interface CommentListener {
	public void onCommentReceived(String comment);
}