Java Calendar Millisecond elapsedMillis(Calendar before, Calendar after)

Description

Retrieve the amount of elapsed milliseconds between the two given calendars.

License

Apache License

Parameter

Parameter	Description
before	The first calendar with expected date before the second calendar.
after	The second calendar with expected date after the first calendar.

Exception

Parameter	Description
IllegalArgumentException	If the first calendar is dated after the second calendar.

Return

The amount of elapsed milliseconds between the two given calendars.

Declaration

public static long elapsedMillis(Calendar before, Calendar after) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.util.Calendar;

public class Main {
    /**/*from w  w w  .  j  a  va  2  s .c o m*/
     * Retrieve the amount of elapsed milliseconds between the two given calendars.
     * @param before The first calendar with expected date before the second calendar.
     * @param after The second calendar with expected date after the first calendar.
     * @return The amount of elapsed milliseconds between the two given calendars.
     * @throws IllegalArgumentException If the first calendar is dated after the second calendar.
     */
    public static long elapsedMillis(Calendar before, Calendar after) {
        return elapsedMillis(before, after, 1); // 1ms is apparently 1ms.
    }

    /**
     * Retrieve the amount of elapsed milliseconds between the two given calendars and directly
     * divide the outcome by the given factor. E.g.: if the division factor is 1, then you will get
     * the elapsed milliseconds unchanged; if the division factor is 1000, then the elapsed
     * milliseconds will be divided by 1000, resulting in the amount of elapsed seconds.
     * @param before The first calendar with expected date before the second calendar.
     * @param after The second calendar with expected date after the first calendar.
     * @param factor The division factor which to divide the milliseconds with, expected to be at
     * least 1.
     * @return The amount of elapsed milliseconds between the two given calendars, divided by the
     * given factor.
     * @throws IllegalArgumentException If the first calendar is dated after the second calendar or
     * if the division factor is less than 1.
     */
    private static long elapsedMillis(Calendar before, Calendar after, int factor) {
        checkBeforeAfter(before, after);
        if (factor < 1) {
            throw new IllegalArgumentException("Division factor '" + factor + "' should not be less than 1.");
        }
        return (after.getTimeInMillis() - before.getTimeInMillis()) / factor;
    }

    /**
     * Check if the first calendar is actually dated before the second calendar.
     * @param before The first calendar with expected date before the second calendar.
     * @param after The second calendar with expected date after the first calendar.
     * @throws IllegalArgumentException If the first calendar is dated after the second calendar.
     */
    private static void checkBeforeAfter(Calendar before, Calendar after) {
        if (before.after(after)) {
            throw new IllegalArgumentException("The first calendar should be dated before the second calendar.");
        }
    }
}

Related

1. calendar(long millis)
2. calendarToGMTMillis(Calendar cal)
3. calendarToGMTMillis(Calendar cal)
4. clearCalendarMillisecond(Calendar cal)
5. getCalendarXDaysFromY(long startTimeInMillis, int daysFromStartDate)
6. getDateMilliseconds(Calendar pDate)
7. getLastMilli(Calendar cal)
8. getMillisecond(Calendar calendar)