public?class?idb02251210
{
???public?static?void?main（String?args[]）
???{
??????//Here?is?the?main?function
??????System.out.println（“This?is?a?barber?shop?with?5?chairs?for?waiting.“）;
??????System.out.println（“Here?is?20?customers?want?to?barber.“）;
??????System.out.println（“Firstthe?barber?is?sleeping?for?there?is?no?customer.“）;
??????Database?server?=?new?Database（）;

??????Barber[]?barberArray?=?new?Barber[NUM_OF_BARBER];

??????for?（int?i?=?0;?i???????{
?????????barberArray[i]?=?new?Barber（i?server）;
?????????barberArray[i].start（）;
?????????try?{//this?try?is?for?controling?the?speed?of?everyone?who?go?into?the?barber?shop
??????????barberArray[i].sleep（1000-20*i）;
????????}
????????catch?（InterruptedException?f）?{
????????}

??????}


???}

???private?static?final?int?NUM_OF_BARBER?=?20;

}

class?Database
{
???public?Database（）?{//set?the?data
??????waitCount?=?0;
??????maxCustomer?=?5;
??????mutex?=?new?Semaphore（1）;
??????db?=?new?Semaphore（maxCustomer?+?1）;
???}

???//?customers?and?barber?will?call?this?to?nap
???public?static?void?napping（）?{
?????int?sleepTime?=?（int）?（NAP_TIME?*?Math.random（）?）;
?????try?{?Thread.sleep（sleepTime*100）;?}
?????catch（InterruptedException?e）?{}
???}


???public?int?startWait（）?{//customers?begin?to?go?into?the?barber?shop
??????db.P（）;

??????++waitCount;//the?number?of?customers?add?one
??????System.out.println（“There?are?“?+?waitCount?+?“?chairs?occupied.“）;

??????if?（waitCount?????????{?mutex.P（）;}
??????waitCount--;
??????db.V（）;//the?number?of?customers?substract?one

??????return?waitCount;
???}

???public?int?endWait（）?{//there?are?no?cuostomers?and?barber?begin?to?sleep
??????db.P（）;

??????if?（waitCount?==?0）
??????{
???????????System.out.println（“The?barber?begin?to?sleep?again.“）;
??????}
??????mutex.V（）;

??????db.V（）;

??????System.out.println（“There?are?“?+?waitCount?+?“?chairs?occupied.“）;
??????return?waitCount;
???}


???private?int?waitCount;
???public?int?maxCustomer;
???Semaphore?mutex;??//?controls?access?to?readerCount
???Semaphore?db;?????//?controls?access?to?the?database

???private?static?final?int?NAP_TIME?=?25;
}

class?Barber?extends?Thread
{
???public?Barber（int?r?Database?db）
???{
??????barberNum?=?r;
??????server?=?db;
??????isFull?=?false;
???}

public?void?run（）
???{
???int?c;

?????while?（true）//people?is?begin?the?detail?behavior
?????{
???????//System.out.println（“customer-“?+?barberNum?+?“?is?going.“）;
???????Database.napping（）;

???????System.out.println（“customer-“?+?barberNum?+?“?enter?shop.“）;
???????c?=?server.startWait（）;

???????if（c?>=?server.maxCustomer）
???????{
?????????????System.out.println（“customer-“?+?barberNum?+?“have?to?go?away?for?no?chairs.“）;
?????????????isFull?=?true;
???????}

???????//?you?have?access?to?have?barbering
???????if（c????????{
?????????????System.out

?屬性????????????大小?????日期????時間???名稱
-----------?---------??----------?-----??----

?????文件???????4001??2004-06-10?22:43??SleepingBarber.java

-----------?---------??----------?-----??----

?????????????????4219????????????????????2