PrimeCalendar provides all the java.util.Calendar functionalities for Persian, Hijri, and Japanese dates. PrimeCalendar can be used in every JVM-based projects such as Java/kotlin applications, Android apps, etc.

This library contains three types of calendar systems as well as their conversion to each other.

PrimeCalendar is available on MavenCentral to download using build tools systems.

Add the following lines to your build.gradle file:

dependencies {
    implementation 'com.aminography:primecalendar:1.7.0'
}

Add the following lines to your pom.xml file:

<dependencies>
    <dependency>
        <groupId>com.aminography</groupId>
        <artifactId>primecalendar</artifactId>
        <version>1.7.0</version>
    </dependency>
</dependencies>

Calendar objects can be instantiated by the class constructors or using CalendarFactory.

Java

PrimeCalendar calendar = new PersianCalendar();
// or
PrimeCalendar calendar = CalendarFactory.newInstance(CalendarType.PERSIAN);

Kotlin

val calendar = HijriCalendar()
// or
val calendar = CalendarFactory.newInstance(CalendarType.HIJRI)

Exactly all of the standard Calendar functionalities are implemented in PrimeCalendar including set, add, roll, etc.
To see list of methods and fields, refer to the wiki page.

val civil = CivilCalendar()
civil.set(2019, 5, 17)
println(civil.longDateString)

civil.set(Calendar.DAY_OF_YEAR, 192)
println(civil.longDateString)

civil.add(Calendar.WEEK_OF_YEAR, 14)
println(civil.longDateString)

civil.roll(Calendar.DAY_OF_WEEK, -3)
println(civil.longDateString)

---------------------------
> Monday, 17 June 2019
> Thursday, 11 July 2019
> Thursday, 17 October 2019
> Monday, 14 October 2019

Conversion of dates to each other is simply possible by calling the converter methods.

// Converting calendar instance to PersianCalendar:
val persian = calendar.toPersian()

// Converting calendar instance to HijriCalendar:
val hijri = calendar.toHijri()

// Converting calendar instance to CivilCalendar:
val civil = calendar.toCivil()

// Converting calendar instance to JapaneseCalendar:
val japanese = calendar.toJapanese()

Also, it is possible to convert an instance of java.util.Calendar to an instance of PrimeCalendar. For example:

import java.util.Calendar

val calendar = Calendar.getInstance()

// Converting to PersianCalendar:
val persian = calendar.toPersian()

There is a different way to use get, set, and add methods. Using operators you can do it much simpler. Suppose that the calendar is an instance of PrimeCalendar:

get

val year = calendar.get(Calendar.YEAR)

// equivalent operations:
val year = calendar[Calendar.YEAR]
val year = calendar.year

set

calendar.set(Calendar.MONTH, 7)

// equivalent operations:
calendar[Calendar.MONTH] = 7
calendar.set(Month(7))
calendar.set(7.month)
calendar.month = 7

add

calendar.add(Calendar.DAY_OF_MONTH, 27)

// equivalent operations:
calendar[Calendar.DAY_OF_MONTH] += 27
calendar += DayOfMonth(27)
calendar += 27.dayOfMonth

You can localize digits, month names, and week day names by passing locale in constructor. For Persian and Hijri calendars, the default locale is set to Farsi and Arabic respectively.

val persian = PersianCalendar()
println(persian.longDateString)

---------------------------
> پنج‌شنبه، ۲۳ خرداد ۱۳۹۸

val persian = PersianCalendar(Locale.ENGLISH)
println(persian.longDateString)

---------------------------
> Thursday, 23 Khordad 1398

• ThreeTen-Backport (https://www.threeten.org/threetenbp)

• Migrating to MavenCentral.

• Improving Arabic digits.

• Adding getter/setter field for all the calendar fields, such as dayOfWeek, hour, etc.
• Adding date conversion extension functions for java.util.Calendar instances.
• Adding calendar fields extensions for numbers, e.g. calendar += 27.dayOfMonth

• Japanese month names and other temporal names are changed.
• Month constants are added into calendar classes.

Copyright 2019 Mohammad Amin Hassani.

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.