Java Util Calendar – Report a bug or suggest an improvement See the Java SE documentation for more API references and developer documentation, which contains more detailed, developer-oriented descriptions with conceptual overviews, definitions of terms, procedures, and working code examples.
Java is a trademark or registered trademark of Oracle and/or its affiliates in the United States and other countries. Copyright © 1993, 2018, Oracle and/or its affiliates, 500 Oracle Parkway, Redwood Shores, CA 94065 USA. All rights reserved.
Java Util Calendar
Source: media.cheggcdn.com
Use is subject to license terms and document distribution policy. When a calendar is in non-friendly mode, it throws an exception if there is a mismatch in its calendar fields. For example, a Gregorian calendar always produces DAY_OF_MONTH values between 1 and the length of the month.
Getting And Setting Calendar Field Values
A non-toxic Gregorian calendar throws an exception when calculating its time or calendar field values if an out-of-range field value is set. Like other locale-sensitive classes, Calendar provides a class method, getInstance, to obtain a generally useful object of this type.
The Calendar getInstance method returns a Calendar object whose calendar fields have been initialized with the current date and time: the values of other calendar fields can be counted to determine a set of display names.
For example, if this calendar is a lunisolar calendar system and the year value returned by the YEAR field has a leap month, this method will return month names that contain the leap month name, and month names mapped specifically to their values.
has. year. Note: This standard implementation of Calendar repeatedly calls the roll() version that rolls a unit. This may not always be correct. For example, if the DAY_OF_MONTH field is 31, rolling to February will set it to 28.
Getting And Setting Calendar Field Values
The Gregorian calendar version of this function takes care of this problem. Other subclasses should also override this function to do the right thing. The HOUR_OF_DAY, HOUR and AM_PM fields are treated independently and the resolution rule for time of day is applied.
Deleting one of the fields will not reset the hours of this calendar’s date value. Use Set(Calendar.HOUR_OF_DAY, 0) to reset the hour value. Use the form. To motivate the behavior of add() and roll() , consider a user interface component with increment and decrement buttons for month, day, and year, and an underlying Gregorian calendar.
If the interface reads January 31, 1999 and the user presses the monthly increment button, what should it read? If Set () is used in the basic data implementation, it may read March 3, 1999 .
A better result is February 28, 1999. Moreover, if the user presses the month increment button again, it should read March 31, 1999, net. Mar 28, 1999. Depending on whether to affect large fields by saving the original date and using add() or roll(), the user interface may behave as most users would instinctively expect.
Note: This standard implementation of Calendar repeatedly calls the roll() version that rolls a unit. This may not always be correct. For example, if the DAY_OF_MONTH field is 31, rolling to February will set it to 28.
The Gregorian calendar version of this function takes care of this problem. Other subclasses should also override this function to do the right thing. If you use the WEEK_OF_MONTH or WEEK_OF_YEAR fields, the calendar must determine the first week of the month or year as a reference point.
Source: img-blog.csdnimg.cn
The first week of a month or year is defined as the first seven-day period that begins with getFirstDayOfWeek() and contains at least the least number of days available in InFirstWeek() of that month or year.
week numbered …, -1, 0 before first week; Week 2, 3, … follow it. Note that the average number returned by get() is different. For example, a specific Calendar subclass can name the week before week 1 of the year as week n of the previous year.
Example: Consider a Gregorian calendar initially set to August 31, 1999. Calling set(Calendar.MONTH, Calendar.SEPTEMBER) sets the date to September 31, 1999. This is a temporary internal representation that resolves to October 1, 1999 when getTime() is called.
However, calling set(Calendar.DAY_OF_MONTH, 30) before the call to getTime() sets the date to September 30, 1999, because no recalculation occurs after set(). Add rule 1. The value of the f field after the call minus the value of the f field before the call delta, modulate an overflow that occurred in the f field.
Overflow occurs when a field value exceeds its range, resulting in the next larger field being incremented or decremented and the field value reset to its range. If there is a conflict in the calendar field values, the calendar will take precedence over the most recently set calendar fields.
Below are the default combinations of calendar fields. The last set is the last combination determined by the single field. This method obtains the minimum number of days required in the first week of the year;
For example, if the first week is defined as containing the first day of the first month of a year, this method returns 1 . Add rule 1. The value of the f field after the call minus the value of the f field before the call delta, modulate an overflow that occurred in the f field.
Overflow occurs when a field value exceeds its range, resulting in the next larger field being incremented or decremented and the field value reset to its range. Example: Consider a Gregorian calendar initially set to August 31, 1999.
Calling add(Calendar.MONTH, 13) sets the calendar to September 30, 2000. Adding rule 1 sets the MONTH field to September, because adding 13 months becomes September of the following year. Since DAY_OF_MONTH cannot be 31 in September in a Gregorian calendar, adding rule 2 sets DAY_OF_MONTH to 30, the closest possible value.
Although it is a small field, DAY_OF_WEEK is not processed by rule 2, because it is expected to change as the month changes in a Gregorian calendar. Current date: Mon Apr 09 19:26:10 IST 2018 10 days ago: Fri Mar 30 19:26:10 IST 2018 3 months later: Sat Jun 30 19:26:10 IST 2018 4 years later: Thu Jun 30 19:26:10 IST 2018
26:10 IST 2022 Maximum number of days in a week: 7 Maximum number of weeks in a year: 53 Minimum number of days in a week: 1 Minimum number of weeks in a year: 1 Submit a bug or feature For more API reference and developer documentation, see Java SE documentation.
This documentation contains more detailed, developer-targeted descriptions with conceptual overviews, definitions of terms, procedures, and working code examples. Copyright © 1993, 2020, Oracle and/or its affiliates. all rights reserved. Use is subject to license terms. See also redistribution policy documents.
Source: www.btechsmartclass.com
For example, if this calendar is the Gregorian calendar and its date is 2005-01-01, the string representation of the MONTH field is “January” in long style or “Jana” in short style in English. However, there is no string representation for the DAY_OF_MONTH field, and this method returns null.
In this line (int space = 1; space <= firstDayEachMonth; space++) you can completely ignore the firstDayEachMonth result and use your firstDayYear counter. This counter has the starting weekday of the year and is incremented every day.
Also, you need to define whether your week starts at 0 or 1. * If, for whatever reason, you’re stuck with Java 6 or Java 7, you can use ThreeTen’s backport, which backs up much of the java.time functionality to Java 6 and 7.
If you are working on an Android project and your Android API level is not yet compatible with Java-8, check out the Java 8+ API available via Desugaring and How to use ThreeTenABP in an Android Project.
set(f, value) changes the calendar field to the value f. Additionally, it sets an internal member variable to indicate that the calendar field f has been modified. Even if the calendar field f is changed immediately, the calendar time value in milliseconds is not recalculated until the next call to get(), getTime(), getTimeInMillis(), add(), or roll() is made.
Thus, multiple calls to set() will not trigger multiple unnecessary calculations. As a result of changing a calendar field using set(), other calendar fields may also change, depending on the calendar field, the calendar field value, and the calendar system.
Additionally, calls to the set method after calender field recalculation (f) do not necessarily return the value. Concrete calendar is determined by class. The Calendar class in Java is an abstract class that provides methods to set the date between a specific moment and a set of calendar fields such as month, year, hour, etc.
The default implementation of this method uses an iterative algorithm to determine the current minimum value for the calendar field. Subclasses should, if possible, override this with a more efficient implementation – in most cases they can return getMinimum().
I am currently working on a problem set that requires me to create a calendar that displays all the months of the year, including the days within the month. However, I’m having problems with the first line spacing every month.
In class we only learned about switch statements, if, else, while, do-while, for loops Calendar has two ways to interpret calendar fields, fun and not fun. If the calendar is in soft mode, it accepts a wider range of calendar field values than it produces.
When a calendar recalculates the calendar field values to return from get (), all calendar fields are normalized. For example, dear The Gregorian calendar defines MONTH == JANUARY, DAY_OF_MONTH == 32 FEBRUARY 1. The java.util.calendar class is an abstract class that provides methods to manipulate calendar fields and convert between a specific moment and a set of calendar fields such as YEAR, MONTH, DAY_OF_MONTH, HOUR.
Get the date of the next week Following are the important points about calendar – Calendar field values can be set by calling set methods. Any field value set in a calendar is not interpreted until it is needed to calculate its time value (milliseconds from epoch) or the values of the calendar fields.
Source: i.ytimg.com
Call get, getTimeInMillis, getTime, add and roll such calculations include. package com.w3spoint; import java.util.calendar; public class CalendarTest { public static void main(String args[]){ Calendar calendar = Calendar.getInstance(); System.out.println(“Current Date: ” + calendar.getTime()); calendar.add(calendar.DATE, -10); System.out.println(“10 days ago: ” + calendar.getTime());
calendar.add(calendar.MONTH, 3); System.out.println(“After 3 months: ” + calendar.getTime()); calendar.add(calendar.YEAR, 4); System.out.println(“After 4 years: ” + calendar.getTime()); int maximum = calendar.getMaximum(Calendar.DAY_OF_WEEK); System.out.println(“Maximum number of days in week: ” + max); maximum = calendar.getMaximum(Calendar.WEEK_OF_YEAR); System.out.println(“Maximum number of weeks in year: ” + max);
int minimum = calendar.getMinimum(Calendar.DAY_OF_WEEK); System.out.println(“Minimum number of days in week: ” + minimum); Minimum = calendar.getMinimum(Calendar.WEEK_OF_YEAR); System.out.println(“Minimum number of weeks in year: ” + minimum); } } The HOUR_OF_DAY, HOUR and AM_PM fields are treated independently and the resolution rule for time of day is applied.
Deleting one of the fields will not reset the hours of this calendar’s date value. Use Set(Calendar.HOUR_OF_DAY, 0) to reset the hour value. Use the form. To motivate the behavior of add() and roll() , consider a user interface component with increment and decrement buttons for month, day, and year, and an underlying Gregorian calendar.
If the interface reads January 31, 1999 and the user presses the monthly increment button, what should it read? If Set () is used in the basic data implementation, it may read March 3, 1999 .
A better result is February 28, 1999. Moreover, if the user presses the month increment button again, it should read March 3
1, 1999, net. Mar 28, 1999. Depending on whether to affect large fields by saving the original date and using add() or roll(), the user interface may behave as most users would instinctively expect.
A calendar object can produce any calendar field value required to implement date-time formatting for a particular language and calendar style (for example, Japanese-Gregorian, Japanese-Traditional). Calendar defines the range of values returned by specific calendar fields, as well as their meaning.
For example, the first month of the calendar method has the value MONTH == JANUARY for all calendars. Other values are defined by the concrete subclass, such as ERA. See individual field documentation and subclass documentation for details.
Values of other calendar fields can be entered to determine a set of display names. For example, if this calendar is a lunisolar calendar system and the year value returned by the YEAR field has a leap month, this method will return month names that contain the leap month name, and month names mapped specifically to their values.
has. year. Like other locale-sensitive classes, Calendar provides a class method, getInstance, to obtain a generally useful object of this type. The Calendar getInstance method returns a Calendar object whose calendar fields have been initialized with the current date and time: The standard implementation of this method uses an iterative algorithm to determine the current minimum value for the calendar field.
උපපංති, හැකි නම්, වඩාත් කාර්යක්ෂම ක්රියාත්මක කිරීමකින් මෙය අභිබවා යා යුතුය – බොහෝ අවස්ථාවලදී ඔවුන්ට getMinimum() ආපසු ලබා දිය හැක. සකසන්න (f, අගය) දින දර්ශන ක්ෂේත්රය f අගයට වෙනස් කරයි. මීට අමතරව, එය දින දර්ශන ක්ෂේත්රය f වෙනස් කර ඇති බව දැක්වීමට අභ්යන්තර සාමාජික විචල්යයක් සකසයි.
f යන දින දර්ශන ක්ෂේත්රය වහා වෙනස් කළද, ඊළඟ ඇමතුම ලබා ගන්නා තෙක් (), getTime(), getTimeInMillis(), add(), හෝ roll() සිදු කරන තෙක් මිලි තත්පර වල දින දර්ශන කාල අගය නැවත ගණනය නොකෙරේ. මේ අනුව, සැකසීමට බහු ඇමතුම් () බහු අනවශ්ය ගණනය කිරීම් අවුලුවන්නේ නැත.
set() භාවිතයෙන් දින දර්ශන ක්ෂේත්රයක් වෙනස් කිරීමේ ප්රතිඵලයක් ලෙස, දින දර්ශන ක්ෂේත්රය, දින දර්ශන ක්ෂේත්ර අගය සහ දින දර්ශන පද්ධතිය අනුව අනෙකුත් දින දර්ශන ක්ෂේත්ර ද වෙනස් විය හැක. මීට අමතරව, දින දර්ශන ක්ෂේත්ර නැවත ගණනය කිරීමෙන් පසු ඇමතුම් සිට සකසන ලද ක්රමයට අගය ලබා දීම (f) අවශ්යයෙන්ම ලබා නොදේ.
කොන්ක්රීට් කැලැන්ඩර පන්තිය විසින් නිශ්චිතව තීරණය කරනු ලැබේ.
