de.micmun.android.workdaystarget.DayCalculator.java Source code

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Here is the source code for de.micmun.android.workdaystarget.DayCalculator.java

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/**
 * Copyright 2013-2014 by Michael Munzert
 *
 * This program is free software: you can redistribute it and/or modify it under 
 * the terms of the GNU >General Public License as published by the 
 * Free Software Foundation, either version 3 of the License, or >
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but 
 * WITHOUT ANY WARRANTY; >without even the implied warranty of MERCHANTABILITY 
 * or FITNESS FOR A PARTICULAR PURPOSE. >See the GNU General Public License 
 * for more details.
 *
 * You should have received a copy of the GNU General Public License along with 
 * this program. If not, see >http://www.gnu.org/licenses/.
 */

package de.micmun.android.workdaystarget;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;

/**
 * Calculates the difference to target in days.
 *
 * @author MicMun
 * @version 1.2, 22.05.2014
 */
public class DayCalculator {
    private static final String TAG = "DayCalculator";
    private static final int POS_HOLIDAY = 7; // position of holiday
    private static final int POS_SUNDAY = 6; // position of sunday
    private Calendar today = null;
    private Calendar target = null;

    /**
     * Creates a new DayCalculator with target date.
     */
    public DayCalculator() {
        today = Calendar.getInstance();
        target = Calendar.getInstance();
        setMidnight(today);
    }

    /**
     * Returns the number of days between today and target, skipped days in
     * appliance of checkedDays.
     *
     * @param t           Date of the target, to which to calculate the working days.
     * @param checkedDays Array with boolean flags, which says if a weekday should count
     *                    or not.
     * @return days to target.
     * @throws JSONException if an error occurs while getting the holidays from web service.
     */
    public int getDaysLeft(Date t, boolean[] checkedDays) throws JSONException {
        // sets target time at midnight
        target.setTime(t);
        setMidnight(target);

        int sign = 1;

        if (target.getTimeInMillis() < today.getTimeInMillis()) {
            Calendar tmp = Calendar.getInstance();
            tmp.setTimeInMillis(target.getTimeInMillis());
            target.setTimeInMillis(today.getTimeInMillis());
            today.setTimeInMillis(tmp.getTimeInMillis());
            sign = -1; // negative days in the past
        }

        // Holidays
        ArrayList<Date> holidays = getHolidays();

        // current time
        Calendar curr = Calendar.getInstance();
        curr.setTime(today.getTime());

        int count = 0;

        while (curr.getTimeInMillis() != target.getTimeInMillis()) {
            curr.add(Calendar.DAY_OF_MONTH, 1);
            int dayOfWeek = curr.get(Calendar.DAY_OF_WEEK);

            if (!checkedDays[POS_HOLIDAY] && holidays.contains(curr.getTime())) {
                continue;
            } else if (!checkedDays[POS_SUNDAY] && dayOfWeek == Calendar.SUNDAY) {
                continue;
            } else if (dayOfWeek != Calendar.SUNDAY && !checkedDays[dayOfWeek - Calendar.MONDAY]) {
                continue;
            }
            count++;
        }

        count *= sign; // if target is in the past, sign == -1

        return count;
    }

    /**
     * Returns the list with holydays between now and target.
     *
     * @return the list with holydays between now and target.
     * @throws JSONException if parsing the holidays fails.
     */
    private ArrayList<Date> getHolidays() throws JSONException {
        ArrayList<Date> holidays = new ArrayList<Date>();

        String basisUrl = "http://kayaposoft.com/enrico/json/v1.0/"
                + "?action=getPublicHolidaysForDateRange&fromDate=%s&toDate=%s" + "&country=ger&region=Bavaria";
        SimpleDateFormat sdf = new SimpleDateFormat("dd-MM-yyyy", Locale.getDefault());

        String url = String.format(basisUrl, sdf.format(today.getTime()), sdf.format(target.getTime()));
        BufferedReader br = null;
        String text = null;

        try {
            URL httpUrl = new URL(url);
            HttpURLConnection con = (HttpURLConnection) httpUrl.openConnection();
            con.setRequestMethod("GET");
            con.connect();
            InputStream is = con.getInputStream();
            br = new BufferedReader(new InputStreamReader(is));
            StringBuffer sb = new StringBuffer();
            String line;

            while ((line = br.readLine()) != null) {
                sb.append(line);
                sb.append('\n');
            }
            br.close();
            text = sb.toString();
        } catch (MalformedURLException e) {
            System.err.println("FEHLER: " + e.getMessage());
            holidays = null;
        } catch (IOException e) {
            System.err.println("FEHLER: " + e.getMessage());
            holidays = null;
        } finally {
            if (br != null) {
                try {
                    br.close();
                } catch (IOException ignored) {
                }
            }
        }

        if (text != null) {
            JSONArray array = new JSONArray(text);
            for (int i = 0; i < array.length(); ++i) {
                JSONObject h = array.getJSONObject(i);
                JSONObject o = h.getJSONObject("date");
                int day = o.getInt("day");
                int month = o.getInt("month");
                int year = o.getInt("year");
                Calendar cal = Calendar.getInstance();
                cal.set(Calendar.DAY_OF_MONTH, day);
                cal.set(Calendar.MONTH, month - 1);
                cal.set(Calendar.YEAR, year);
                setMidnight(cal);
                holidays.add(cal.getTime());
            }
        }

        return holidays;
    }

    /**
     * Sets the time of given calendar to midnight.
     *
     * @param c calendar to set the time.
     */
    private void setMidnight(Calendar c) {
        c.set(Calendar.HOUR_OF_DAY, 0);
        c.set(Calendar.MINUTE, 0);
        c.set(Calendar.SECOND, 0);
        c.set(Calendar.MILLISECOND, 0);
    }
}