Can I lock a table in a session bean?

[keithbannister]

Hi,

I'm trying to create a session bean that checks the contents of a potential new record against a table before adding that record to the table. The table is a list of (funnily enough) hotel bookings. I want to make sure that the booking dates don't clash for a particular room. Because a booking has a start date and end date, it's not sufficient to have a compound primary key based on dates.

I'm using EJB3 on JBOSS 4

If I were doing it in normal java it would look something like:

List<Booking> bookings = ....
Object bookingLock = new Object();


public void create(Boooking booking) {
 synchronized(bookingLock) {
 if (!roomBookedForInterval(booking)) {
 saveBooking(booking)
 }
 }
}

private boolean roomBookedForInterval(Booking booking) {
 for(Booking b : bookings) {
 if (b.endDate() > booking.startDate() ||
 b.startDate() < booking.endDate() ) {

 return true;
 }
 }

 return false;
}

private void saveBooking(Booking booking) {
 bookings.add(booking);
}

My question is, what is the EJB3 equivalent of the

synchronized{}

block? IS it a transaction? If so, how does it work?