Java весна 2013 лекция 3

public final boolean compareAndSet(int expect, int update) {
return unsafe.compareAndSwapInt(this, valueOffset, expect, update);
}
public final int incrementAndGet() {
while (true) {
int current = get(); //get() возвращает текущее значение (volatile)
int next = current + 1;
if (compareAndSet(current, next))
return next;
}
}

public class Address {
static private AtomicInteger abonentIdCreator = new AtomicInteger();
final private int abonentId;
public Address(){
this.abonentId = abonentIdCreator.incrementAndGet();
}
public int hashCode() {
return abonentId;
}
}
public interface Abonent {
Address getAddress();
}

public abstract class Msg {
final private Address from;
final private Address to;
public Msg(Address from, Address to){
this.from = from;
this.to = to;
}
protected Address getFrom(){
return from;
}
protected Address getTo(){
return to;
}
public abstract void exec(Abonent abonent);
}

public abstract class MsgToFrontend extends Msg {
public MsgToFrontend(Address from, Address to) {
super(from, to);
}
public void exec(Abonent abonent) {
if( abonent instanceof Frontend ){
exec((Frontend)abonent);
}
}
public abstract void exec(Frontend frontend);
}

public class MsgUpdateUserId extends MsgToFrontend {
final private int sessionId;
final private int userId;
public GameInfoMsg(Address from, Address to, int sessionId, int userId) {
super(from, to);
this. sessionId = sessionId;
this. userId = userId;
}
public void exec(Frontend frontend) {
frontend.updateUserId(sessionId, userId);
}
}

Msg
MsgToAS MsgToFrontend
MsgUpdateUserIdMsgGetUserId
- Address from
- Address to
- String name
- Integer sessionId
- Integer sessionId
- Integer userId

private Map<Address, ConcurrentLinkedQueue<Msg>> messages
= new HashMap<Address, ConcurrentLinkedQueue<Msg>>();
public void sendMessage(Msg message){
Queue<Msg> messageQueue = messages.get(message.getTo());
messageQueue.add(message);
}
public void execForAbonent(Abonent abonent) {
Queue<Msg> messageQueue = messages.get(abonent.getAddress());
while(!messageQueue.isEmpty()){
Msg message = messageQueue.poll();
message.exec(abonent);
}
}

public class AddressService {
private Map<Class<?>, Address> addresses = new HashMap<Class<?>, Address>();
public Address getAddress(Class<?> abonentClass) {
return addresses.get(abonentClass);
}
public void setAddress(Abonent abonent) {
addresses.put(abonent.getClass(), abonent.getAddress());
}
}

public void run() {
while (true) {
messageSystem.execForAbonent(this);
Thread.sleep(TICK_TIME);
}
}

14. Плюсы и минусы многопоточных приложений
15. Способы взаимодействия потоков
16. java.util.concurrent
17. MessageSystem. Address и Abonent

Java весна 2013 лекция 3

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Java весна 2013 лекция 3