Java中的事件通知
在java中,我对观察者模式或JMS感到非常困惑。我想使用下面的事件通知让我们忘掉那些JMS或观察家吧,你认为这是可能的还是可行的?如果是,如何完成Java中的事件通知,java,events,Java,Events,在java中,我对观察者模式或JMS感到非常困惑。我想使用下面的事件通知让我们忘掉那些JMS或观察家吧,你认为这是可能的还是可行的?如果是,如何完成 newSalesOrder = new SalesOrder(); newSalesOrder.notified("new SalesOrder order ID="+orderId); EventRegister.bindEvent(SalesOrder.class, Delivery.class); EventRegister.bindEve
newSalesOrder = new SalesOrder();
newSalesOrder.notified("new SalesOrder order ID="+orderId);
EventRegister.bindEvent(SalesOrder.class, Delivery.class);
EventRegister.bindEvent(SalesOrder.class, Warehouse.class);
////////////
Delivery delivery = new Delivery();
delivery.listerning(new Event(source){
if(source == SalesOrder.class){
}
});
//////////
Warehouse warehouse = new Warehouse();
warehouse.listerning(new Event(source){
if(source == SalesOrder.class){
}
});
///////////
EventRegister{
static bindEvent(Class source, Class destination){
//???
}
}
您需要注册(绑定)对象而不是类。您可以在EventRegister中保持注册列表的静态,但我认为最好在SalesOrder中将它们作为实例。因此,这将是:
import java.util.ArrayList;
import java.util.List;
public class Test {
public static void main(String[] args) {
SalesOrder mySalesOrder = new SalesOrder();
Warehouse myWarehouse = new Warehouse();
mySalesOrder.addListener(myWarehouse);
Delivery myDelivery = new Delivery();
mySalesOrder.addListener(myDelivery);
Event myEvent = new Event();
// Now 'myDelivery' and 'myWarehouse' objects will receive 'myEvent'
// object on their 'onEvent(Event event)' method
System.out.println("Event to be published: " + myEvent);
mySalesOrder.publishEvent(myEvent);
}
}
interface Listener {
public void onEvent(Event event);
}
class Event {
// Add reqired detail here!
}
class SalesOrder {
private List<Listener> listeners = new ArrayList<Listener>();
public void addListener(Listener listener) {
listeners.add(listener);
}
public void removeListener(Listener listener) {
listeners.remove(listener);
}
// Use proper access modifier
public void publishEvent(Event event) {
System.out.println(this + " is goint to publish " + event
+ " to " + listeners + " listeners.");
for (Listener listener : listeners) {
listener.onEvent(event);
}
}
// ...
}
class Warehouse implements Listener {
public void onEvent(Event event) {
// Do something when event received
System.out.println(event + " received at " + this);
}
// ...
}
class Delivery implements Listener {
public void onEvent(Event event) {
// Do something when event received
System.out.println(event + " received at " + this);
}
// ...
}
import java.util.ArrayList;
导入java.util.List;
公开课考试{
公共静态void main(字符串[]args){
SalesOrder mySalesOrder=新SalesOrder();
仓库myWarehouse=新仓库();
mySalesOrder.addListener(myWarehouse);
交货期myDelivery=新交货期();
mySalesOrder.addListener(myDelivery);
Event myEvent=新事件();
//现在“myDelivery”和“myWarehouse”对象将接收“myEvent”
//对象的“onEvent(Event)”方法上的
System.out.println(“要发布的事件:+myEvent”);
mySalesOrder.publishEvent(myEvent);
}
}
接口侦听器{
公共无效事件(事件);
}
班级活动{
//在此添加所需的详细信息!
}
类销售订单{
私有列表侦听器=新的ArrayList();
公共void addListener(侦听器侦听器){
添加(侦听器);
}
公共void RemovelListener(侦听器侦听器){
删除(侦听器);
}
//使用适当的访问修饰符
公共事件(事件){
System.out.println(此+“将发布”+事件
+“到”+侦听器+“侦听器”);
for(侦听器:侦听器){
onEvent(事件);
}
}
// ...
}
类仓库实现侦听器{
公共无效事件(事件){
//收到事件后做某事
System.out.println(事件+”在“+此”接收);
}
// ...
}
类传递实现侦听器{
公共无效事件(事件){
//收到事件后做某事
System.out.println(事件+”在“+此”接收);
}
// ...
}
如果您运行它,它将打印如下内容:
待公布的活动:Event@190d11
SalesOrder@a90653即将出版Event@190d11到[Warehouse@de6ced, Delivery@c17164]听众
Event@190d11在收到Warehouse@de6ced
Event@190d11在收到Delivery@c17164
这是一个琐碎的例子,在实际的用例中,你可以考虑使用线程安全的实现和重构,使用构图或继承从Suffice订单中注册。
你还没有真正描述你想要的东西。您刚刚给出了一些方法签名,但没有真正表明您希望从它们那里获得的行为(甚至您的“事件”来自何处)……为什么不允许使用观察者模式这一看似武断的限制?