trendulo.web.date.DateConverter.java Source code

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Here is the source code for trendulo.web.date.DateConverter.java

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// =================================================================================================
// Copyright 2012 Jared Winick
// -------------------------------------------------------------------------------------------------
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this work except in compliance with the License.
// You may obtain a copy of the License in the LICENSE file, or at:
//
//  http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// =================================================================================================

package trendulo.web.date;

import java.util.ArrayList;
import java.util.List;

import org.joda.time.DateTime;
import org.joda.time.DateTimeZone;
import org.joda.time.format.DateTimeFormat;
import org.joda.time.format.DateTimeFormatter;

public class DateConverter {

    // i don't like this. we really need to get everything back to UTC
    private static DateTimeZone mdtDateTimeZone = DateTimeZone.forOffsetHours(-6);

    public static long dateStringToTimestamp(String date) {

        return dateStringToTimestamp(date, DateTimeZone.UTC);
    }

    public static long dateStringToTimestamp(String date, DateTimeZone dateTimeZone) {
        long timestamp = 0;
        DateTimeFormatter formatter = null;

        // Month
        if (date.length() == 6) {
            formatter = DateTimeFormat.forPattern("yyyyMM");
        } else if (date.length() == 8) {
            formatter = DateTimeFormat.forPattern("yyyyMMdd");
        } else if (date.length() == 10) {
            formatter = DateTimeFormat.forPattern("yyyyMMddHH");
        }

        if (formatter != null) {
            timestamp = formatter.withZone(dateTimeZone).parseMillis(date);
        }

        return timestamp;
    }

    /**
     * Get the date string for the start of time period days days ago from timestamp
     * @param days the number of days in the past from timestamp
     * @param timestamp the time reference
     * @return a dateString in the form of yyyyMMdd or yyyyMMddHH
     */
    public static String getStartDateString(int days, long timestamp) {
        DateTimeFormatter formatter = getFormatterForDays(days);

        // Do the date arithmetic ( timestamp - days )
        //DateTime dateTime = new DateTime( timestamp, DateTimeZone.UTC );
        DateTime dateTime = new DateTime(timestamp, mdtDateTimeZone);
        DateTime startDateTime = dateTime.minusDays(days);

        //return formatter.withZoneUTC().print( startDateTime );
        return formatter.withZone(mdtDateTimeZone).print(startDateTime);
    }

    public static String getEndDateString(int days, long timestamp) {
        DateTimeFormatter formatter = getFormatterForDays(days);
        //DateTime dateTime = new DateTime( timestamp, DateTimeZone.UTC );
        DateTime dateTime = new DateTime(timestamp, mdtDateTimeZone);
        //return formatter.withZoneUTC().print( dateTime );
        return formatter.withZone(mdtDateTimeZone).print(dateTime);
    }

    private static DateTimeFormatter getFormatterForDays(int days) {
        DateTimeFormatter formatter = null;
        if (days > 30) {
            formatter = DateTimeFormat.forPattern("yyyyMMdd");
        } else {
            formatter = DateTimeFormat.forPattern("yyyyMMddHH");
        }
        return formatter;
    }

    public static List<String> getDateStringsForRange(String startDateString, String endDateString, int days) {

        List<String> dateStrings = new ArrayList<String>();

        long startDate = dateStringToTimestamp(startDateString, mdtDateTimeZone);
        long endDate = dateStringToTimestamp(endDateString, mdtDateTimeZone);

        // determine the dateIncrement. It is either 1 hour or 1 day
        long dateIncrement = 0;
        if (startDateString.length() == 8) {
            dateIncrement = 1 * 24 * 60 * 60 * 1000; // 1 day in milliseconds
        } else if (startDateString.length() == 10) {
            dateIncrement = 1 * 60 * 60 * 1000; // 1 hour in milliseconds
        }

        // loop through all the dates and build the list of date strings
        for (long currentDate = startDate; currentDate <= endDate; currentDate += dateIncrement) {
            dateStrings.add(getEndDateString(days, currentDate));
        }

        return dateStrings;
    }
}