calculate business days including holidays
Nager.Date
You can use the JSON API of Nager.Date project. It supports USA, Canada and Europe. The data available for every year you can save the information in your own database.
Example
//https://github.com/FasterXML/jackson-databind/
ObjectMapper mapper = new ObjectMapper();
MyValue value = mapper.readValue(new URL("http://date.nager.at/api/v1/get/US/2017"), PublicHoliday[].class);
PublicHoliday.class
public class PublicHoliday
{
public String date;
public String localName;
public String name;
public String countryCode;
public Boolean fixed;
public Boolean countyOfficialHoliday;
public Boolean countyAdministrationHoliday;
public Boolean global;
public String[] counties;
public int launchYear;
}
Example JSON data retrieved.
[
{
"date": "2017-01-01",
"localName": "New Year's Day",
"name": "New Year's Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-01-16",
"localName": "Martin Luther King, Jr. Day",
"name": "Martin Luther King, Jr. Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-01-20",
"localName": "Inauguration Day",
"name": "Inauguration Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": false,
"counties": [
"US-DC",
"US-LA",
"US-MD",
"US-VA"
],
"launchYear": null
},
{
"date": "2017-02-20",
"localName": "Washington's Birthday",
"name": "Presidents' Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-05-29",
"localName": "Memorial Day",
"name": "Memorial Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-07-04",
"localName": "Independence Day",
"name": "Independence Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-09-04",
"localName": "Labor Day",
"name": "Labor Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-09-09",
"localName": "Columbus Day",
"name": "Columbus Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": false,
"counties": [
"US-AL",
"US-AZ",
"US-CO",
"US-CT",
"US-DC",
"US-GA",
"US-ID",
"US-IL",
"US-IN",
"US-IA",
"US-KS",
"US-KY",
"US-LA",
"US-ME",
"US-MD",
"US-MA",
"US-MS",
"US-MO",
"US-MT",
"US-NE",
"US-NH",
"US-NJ",
"US-NM",
"US-NY",
"US-NC",
"US-OH",
"US-OK",
"US-PA",
"US-RI",
"US-SC",
"US-TN",
"US-UT",
"US-VA",
"US-WV"
],
"launchYear": null
},
{
"date": "2017-11-10",
"localName": "Veterans Day",
"name": "Veterans Day",
"countryCode": "US",
"fixed": false,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
},
{
"date": "2017-12-23",
"localName": "Thanksgiving Day",
"name": "Thanksgiving Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": 1863
},
{
"date": "2017-12-25",
"localName": "Christmas Day",
"name": "Christmas Day",
"countryCode": "US",
"fixed": true,
"countyOfficialHoliday": true,
"countyAdministrationHoliday": true,
"global": true,
"counties": null,
"launchYear": null
}
]
Let's pretend you have a list containing all the holidays, as you mentioned.
ArrayList<Integer> holidays = ...
Just add a condition to your if condition in your do-while:
do {
startCal.add(Calendar.DAY_OF_MONTH, 1);
if (startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SATURDAY
&& startCal.get(Calendar.DAY_OF_WEEK) != Calendar.SUNDAY
&& !holidays.contains((Integer) startCal.get(Calendar.DAY_OF_YEAR))) {
++workDays;
}
} while (startCal.getTimeInMillis() < endCal.getTimeInMillis());
For simplicity's sake, I've assumed holiday contains dates in the format identical to Calendar.DAY_OF_YEAR.
Since the accepted answer still uses the obsolete Calendar class – here's my two cents using the newer Java Date and Time API available in the java.time package.
You have to get the dates of the holidays from somewhere, there is no standard Java library for it. That would be too localized anyway, since holidays heavily depend on your country and region (except for widely known holidays, such as Christmas or Easter).
You could get them from a holiday API, for instance. In the code below, I've hardcoded them as a Set of LocalDates.
Java 9
LocalDate startDate = LocalDate.of(2012, 3, 7);
LocalDate endDate = LocalDate.of(2012, 6, 7);
// I've hardcoded the holidays as LocalDates
// and put them in a Set
final Set<LocalDate> holidays = Set.of(
LocalDate.of(2018, 7, 4)
);
// For the sake of efficiency, I also put the business days into a Set.
// In general, a Set has a better lookup speed than a List.
final Set<DayOfWeek> businessDays = Set.of(
MONDAY, TUESDAY, WEDNESDAY, THURSDAY, FRIDAY
);
List<LocalDate> allDates =
// Java 9 provides a method to return a stream with dates from the
// startdate to the given end date. Note that the end date itself is
// NOT included.
startDate.datesUntil(endDate)
// Retain all business days. Use static imports from
// java.time.DayOfWeek.*
.filter(t -> businessDays.contains(t.getDayOfWeek()))
// Retain only dates not present in our holidays list
.filter(t -> !holidays.contains(t))
// Collect them into a List. If you only need to know the number of
// dates, you can also use .count()
.collect(Collectors.toList());
Java 8
The method LocalDate.datesUntil is not available in Java 8, so you have to obtain a stream of all dates between those two dates in a different manner. We must first count the total number of days in between using the ChronoUnit.DAYS.between method.
long numOfDaysBetween = ChronoUnit.DAYS.between(startDate, endDate);
Then we must generate a sequence of integers exactly as long as the number of days between the start and end date, and then create LocalDates from it, starting at the start date.
IntStream.iterate(0, i -> i + 1)
.limit(numOfDaysBetween)
.mapToObj(startDate::plusDays)
Now we have a Stream<LocalDate>, and you can then use the remaining part of the Java 9 code. You also need to replace the usage of Set.of(), because it's not available in Java 8. Probably by new HashSet<>(Arrays.asList(MONDAY...FRIDAY)).
I don't have any code samples or anything like that, but I did some searching for you and came across this Stack Overflow thread that has some links to web services that can return holiday dates for you, which may help you get to where you need to be: National holiday web service
The top answer in that thread links to this web service: http://www.holidaywebservice.com/
I'm not sure if using a web service for this type of thing is overkill or not, but surely there is a better way. I apologize, I am not the most experienced programmer so I can't help you as much as I'd like to.