FAQ: Where is the Zmanim API Main Method?

KosherJava Zmanim API FAQ

Question:

Where is the main method?

Answer:

This is a more technical variant of the “How do I install the Zmanim API Program?”, but coming from someone who already knows that it is a Java program that can’t be installed, but assumes that it can be run. The main method is the entry point to a Java program. Since this is a library/API and not a program, it does not have a main method. The code to generate zmanim is spelled out in the How to Use the Zmanim API page. Below is a full example of a very simple zmanim program that outputs sunrise, sof zman krias shema and sunset for the current day in Lakewood, NJ. Please ensure that the Zmanim jar (download) is in your classpath.

/**
 * This program is a simple demonstration of the kosherjava.com Zmanim API.
 * To compile, ensure that the Zmanim Jar is in your classpath.
 */
import com.kosherjava.zmanim.*;
import com.kosherjava.zmanim.util.*;
import java.util.TimeZone;
public class SimpleZmanim{
	public static void main(String [] args) {
		String locationName = "Lakewood, NJ";
		double latitude = 40.096; //latitude of Lakewood, NJ
		double longitude = -74.222; //longitude of Lakewood, NJ
		double elevation = 0; //optional elevation
		//use a Valid Olson Database timezone listed in java.util.TimeZone.getAvailableIDs()
		TimeZone timeZone = TimeZone.getTimeZone("America/New_York");
		//create the location object
		GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
		//create the ZmanimCalendar
		ZmanimCalendar zc = new ZmanimCalendar(location);
		//optionally set the internal calendar. If not set it will default to the current date
		//zc.getCalendar().set(1969, Calendar.FEBRUARY, 8);
		System.out.println("Today's Zmanim for " + locationName);
		System.out.println("Sunrise: " + zc.getSunrise()); //output sunrise
		System.out.println("Sof Zman Shema GRA: " + zc.getSofZmanShmaGRA()); //output Sof Zman Shema GRA
		System.out.println("Sunset: " + zc.getSunset()); //output sunset
	}
}

The following would compile and execute this code (sample from a DOS prompt in Windows).

C:\path\to\code>javac SimpleZmanim.java

C:\path\to\code>java SimpleZmanim

Today's Zmanim for Lakewood, NJ
Sunrise: Thu Nov 05 06:30:27 EST 2009
Sof Zman Shema GRA: Thu Nov 05 09:05:21 EST 2009
Sunset: Thu Nov 05 16:50:02 EST 2009

Please see the Zmanim API documentation for a more complete view of the API.

FAQ: How do I install the Zmanim API Program?

KosherJava Zmanim API FAQ

Question:

How do I install the Zmanim API Program?

Answer:

The Zmanim API is not a program that can be installed, but a Java programming library often referred to as an API (Application Programming Interface). This is a building block to be used by programmers who want to easily include zmanim in their own programs. The Zmanim API allows them to do this with minimal understanding of the way zmanim are calculated. A sample of a program that uses the Zmanim API library is the Zmanim Calendar Generator. The Zmanim Calendar Generator collects user entered location information on the web page and submits this to a small Java program that calculates a year’s worth of zmanim and outputs it as an Excel spreadsheet (using the Apache POI library). A future FAQ may provide a list of current programs that use the Zmanim API.

Plans for a Zmanim API FAQ

KosherJava Zmanim API FAQ
Questions communicated to me via the contact page far exceed the number of comments in the blog. In the hope of clarifying the most common questions related to the Zmanim API and to a lesser degree other parts of this site, I plan on a series of FAQ posts that will hopefully cut down on the number of questions. The list of FAQs may eventually be consolidated into a FAQ page.

Zmanim Calendar Generator Can Now Output Fewer Zmanim

Sunrise Calendar>After numerous requests, the Zmanim Calendar Generator can now output a less extensive list of zmanim. While the “full” calendar option (the default) generates an Excel spreadsheet with 108 columns of zmanim, the “standard” output generates a spreadsheet with 15 columns containing the most commonly used zmanim. The exact list of what constitutes commonly used zmanim is likely to be tweaked over time. The spreadsheet was initially designed for developers as a sample of the various zmanim available in the API. Developers can compare the output of their zmanim using the API, or a ported version of the API to the spreadsheet for accuracy. Based on feedback, many people use it to generate shul calendars and wanted a less daunting list of zmanim.

Zmanim API 1.1 Released


The Zmanim API 1.1 was released early this morning. Information about what changed in this release can be seen in previous posts about various beta and patch releases. A last-minute change involved the removal of the misheyakir calculations commonly used by the Syrian community. The removal was due to the various different minhagim used, and Chacham Yosef Harari-Raful not endorsing any specific one, nor does he include any in his calendar. The API is flexible enough to be used for any calculation wanted by the various Syrian shuls even without “native” support for a built in “Ateret Torah” misheyakir. Some missing JavaDocs were also added.

I would like to again thank Rabbi Rachamim Ashkenazi the publisher of a zmanim calendar for the Syrian Community, and Victor Grazi for his input, testing and technical expertise used for adding the new “Ateret Torah” zmanim.

The main download is the Zmanim 1.1 release zip file that includes source files and JavaDoc documentation. Also available for download (included in the above zip file) is the main zmanim-1.1.jar and the new zmanimAstronomical-1.1.jar that only includes the AstronomicalCalendar and supporting classes. Additional detail on the downloads can be seen on the Zmanim Download page.