Árvores-B: Solução

 
class BTreeConcurrencyController {

		 int nww = 0, nwr = 0, nr = 0, ticket = 0;

		 TicketQueue waiting;

		 key mutex;

		 void readerRequestRead() {

		 		 lock(mutex);

		 		 myTicket = ticket++;

		 		 while ((nww > 0)  (!waiting.iAmTheBest(myTicket))) {

		 		 		 waiting.enter(myTicket,mutex);

		 		 }

		 		 nr++;

		 		 waiting.ok(myTicket);

		 		 unlock(mutex);

		 }

		 void writerRequestRead() {

		 		 lock(mutex);

		 		 myTicket = ticket++;

		 		 while ((nww + nwr > 0)  (!waiting.iAmTheBest(myTicket))) {

		 		 		 waiting.enter(myTicket, mutex);

		 		 }

		 		 nwr++;

		 		 waiting.ok(myTicket);

		 		 unlock(mutex);

		 }