Question

首先，我是线程和共享变量的新手。所以请和我好心;-)

我正在上一个名为Routing的班级。该类接收并处理消息。如果消息的类型为A，则Routing - 对象应将其传递给实现ASender接口的Runnable对象。如果邮件的类型为B，则Routing - 类应将其传递给BSender对象。

但是ASender和BSender对象有共同的变量，应存储在Routing - 对象中。

我现在的想法是在Routing - Object和getter / setter中将变量声明为synchronized / volatile。

这是同步代码的正确方法吗？或者缺少什么？

编辑：添加了基本代码的想法。

RoutingClass

public class Routing {

private synchronized Hashtable<Long, HashSet<String>> reverseLookup;
private ASender asender;
private BSender bsender;

public Routing() {
    //Constructor work to be done here.. 
    reverseLookup = new Hashtable<Long, HashSet<String>>();

}

public void notify(TopicEvent event) {

    if (event.getMessage() instanceof AMessage) {
        asender = new ASender(this, event.getMessage())

    } else if (event.getMessage() instanceof BMessage) {
        bsender = new BSender(this, event.getMessage())

    }
}

public synchronized void setReverseLookup(long l, Hashset<String> set) {
    reverseLookup.put(l, set);

}

public synchronized Hashtable<Long, Hashset<String>> getReverseLookup() {
    return reverseLookup;
}
}

ASender Class

public class ASender implements Runnable {

private Routing routing;
private RoutingMessage routingMessage;

public ASender(Routing r, RoutingMessage rm) {
    routing = r;
    routingMessage = rm;
    this.run();
}

public void run() {
    handleMessage();
}

private void handleMessage() {
    // do some stuff and extract data from the routing message object

    routing.setReverseLookup(somethingToSet)
}
}

Answer 1

一些意见：

Hashtable是一个线程安全的实现，您不需要其他“同步”关键字，请参阅this和this以获取更多信息
避免耦合，尝试使用接口或将哈希表传递给发件人，有关详细信息，请参阅this
根据发件人的数量，您可能希望使用ConcurrentHashMap，这会极大地提高效果，请参阅ConcurrentHashMap and Hashtable in Java和Java theory and practice: Concurrent collections classes

这将结束类似......：

public interface IRoutingHandling {

    void writeMessage(Long key, HashSet<String> value);

}

public class Routing implements IRoutingHandling {

    private final Hashtable<Long, HashSet<String>> reverseLookup;

    private ASender asender;
    private BSender bsender;

    public Routing() {
        //Constructor work to be done here.. 
        reverseLookup = new Hashtable<Long, HashSet<String>>();
    }

    public void notify(TopicEvent event) {
        if (event.getMessage() instanceof AMessage) {
            asender = new ASender(this, event.getMessage())

        } else if (event.getMessage() instanceof BMessage) {
            bsender = new BSender(this, event.getMessage())

        }
    }

    @Override
    public void writeMessage(Long key, HashSet<String> value) {
        reverseLookup.put(key, value);
    }

}

public class ASender implements Runnable {

    private IRoutingHandling _routingHandling;

    public ASender(IRoutingHandling r, RoutingMessage rm) {
        _routingHandling = r;
        routingMessage = rm;
        this.run();
    }

    public void run() {
        handleMessage();
    }

    private void handleMessage() {
        // do some stuff and extract data from the routing message object

        _routingHandling.writeMessage(somethingToSetAsKey, somethingToSetAsValue)
    }

}

读写共享线程变量

1 个答案: