io.horizondb.model.core.util.TimeUtils.java Source code

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Here is the source code for io.horizondb.model.core.util.TimeUtils.java

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/**
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License 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 io.horizondb.model.core.util;

import java.text.ParsePosition;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;

import org.apache.commons.lang.ArrayUtils;
import org.apache.commons.lang.Validate;

import static java.lang.String.format;

/**
 * Utility methods to work with date/time.
 * 
 * @author Benjamin
 */
public final class TimeUtils {

    /**
     * Europe/Berlin time zone.
     */
    public static final TimeZone EUROPE_BERLIN_TIMEZONE = TimeZone.getTimeZone("Europe/Berlin");

    private static final int[] TRUNCATING_FIELDS = new int[] { Calendar.MILLISECOND, Calendar.SECOND,
            Calendar.MINUTE, Calendar.HOUR_OF_DAY, Calendar.DAY_OF_MONTH, Calendar.MONTH, Calendar.YEAR };

    /**
     * Parses the specified <code>String</code> representing a date/time.
     * <p>The supported patterns are: 'yyyy-MM-dd', 'yyyy-MM-dd HH:mm:ss' and 
     * 'yyyy-MM-dd HH:mm:ss.SSS'.</p>
     * 
     * @param dateTime the <code>String</code> representing a date/time.
     * @return the time in millisecond since epoch
     */
    public static long parseDateTime(String dateTime) {

        return parseDateTime(TimeZone.getDefault(), dateTime);
    }

    /**
     * Parses the specified <code>String</code> representing a date/time.
     * <p>The supported patterns are: 'yyyy-MM-dd', 'yyyy-MM-dd HH:mm:ss' and 
     * 'yyyy-MM-dd HH:mm:ss.SSS'.</p>
     * 
     * @param timeZone the date TimeZone
     * @param dateTime the <code>String</code> representing a date/time.
     * @return the time in millisecond since epoch
     */
    public static long parseDateTime(TimeZone timeZone, String dateTime) {

        String pattern = getPattern(dateTime);
        SimpleDateFormat format = new SimpleDateFormat(pattern);

        Calendar calendar = Calendar.getInstance(timeZone);
        calendar.clear();
        calendar.setLenient(false);

        format.setCalendar(calendar);

        Date date = format.parse(dateTime, new ParsePosition(0));

        if (date == null) {
            throw new IllegalArgumentException(format("The value %s cannot be parsed into a valid date", dateTime));
        }
        return date.getTime();
    }

    /**
     * Returns the pattern to use to parse the specified dateTime.
     * 
     * @param dateTime the dateTime
     * @return the pattern to use to parse the specified dateTime
     */
    private static String getPattern(String dateTime) {

        int length = dateTime.length();

        if (length == 10) {
            return "yyyy-MM-dd";
        }

        if (length == 19) {
            return "yyyy-MM-dd HH:mm:ss";
        }

        if (length == 23) {
            return "yyyy-MM-dd HH:mm:ss.SSS";
        }

        throw new IllegalArgumentException(format(
                "The format of the date/time: %s does not match the expected one:" + " yyyy-MM-dd HH:mm:ss.SSS",
                dateTime));
    }

    /**
     * Truncate this date, leaving the field specified as the most significant field.
     * 
     * @param calendar the calendar to truncate
     * @param field the most significant field
     */
    public static void truncate(Calendar calendar, int field) {

        Validate.isTrue(ArrayUtils.contains(TRUNCATING_FIELDS, field),
                "the specified field cannot be used to truncate the specified calendar");

        for (int calendarField : TRUNCATING_FIELDS) {

            if (field == calendarField) {

                return;
            }

            calendar.set(calendarField, calendar.getActualMinimum(calendarField));
        }
    }

    private TimeUtils() {

    }
}