TG History Histogram

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;

public class Parser {


    public static void main(String[] args) throws Exception {
        File file = new File("history.txt");
        BufferedReader reader = new BufferedReader(new FileReader(file));

        SimpleDateFormat dateFormat = new SimpleDateFormat("dd.MM.yyyy hh:mm:ss");

        final Map<String, Integer> dayHourMap = new HashMap<>();

        String line;
        while ((line = reader.readLine()) != null) {
            if (line.matches("[0-9][0-9]\\.[0-9][0-9]\\.[0-9][0-9][0-9]. [0-9][0-9]:[0-9][0-9]:[0-9][0-9].*$")) {
                if (!line.contains("Cupcake")) {
                    continue;
                }

                String[] split = line.split(",");
                Date date = dateFormat.parse(split[0]);

                Calendar cal = Calendar.getInstance();
                cal.setTime(date);

                String day = "" + cal.get(Calendar.DAY_OF_MONTH);
                String hour = "" + cal.get(Calendar.HOUR_OF_DAY);
                String dayHour = "DAY: " + day + " Hour: " + hour;
                if (!dayHourMap.containsKey(dayHour)) {
                    dayHourMap.put(dayHour, 0);
                }
                dayHourMap.put(dayHour, dayHourMap.get(dayHour) + 1);
            }
        }

        histogram(dayHourMap);

        reader.close();
    }

    private static void histogram(Map<String, Integer> map) {
        map.keySet().stream().sorted().forEach(key -> {
            int amount = map.get(key);
            StringBuilder lines = new StringBuilder();
            for (int i = 0; i < amount; i++) {
                lines.append("|");
            }
            lines.append(" ").append(amount);

            if (key.length() <= 14) {
                System.out.printf("%s   => %s\n", key, lines.toString());
            } else if (key.length() <= 15) {
                System.out.printf("%s  => %s\n", key, lines.toString());
            } else {
                System.out.printf("%s => %s\n", key, lines.toString());
            }
        });
    }

}