我试图用rxjava创建一个eventbus，我会抛出一些命令，即使发生错误也会继续。我正在调查onErrorFlatMap，但这已经不存在了，我无法理解并实现非物质化。
这就是我已经拥有的：
我的小测试
public class EventBusTest {
private EventBus eventBus = new EventBus();
@Test
public void test() {
//listeners in service layer
eventBus.on(createOf(BeanA.class))
.subscribe(this::handleBeanAInService1);
eventBus.on(createOf(BeanA.class))
.doOnNext(BeanA::validateBusinessLogic)
.subscribe(this::handleBeanAInService2);
eventBus.on(createOf(BeanB.class))
.subscribe(this::handleBeanBInService);
//incoming requests in rest layer
List<String> incomingCalls = new ArrayList<>();
Collections.addAll(incomingCalls, "firstRequest", "secondRequestErrorOnValidate", "thirdRequest", "fourthRequestErrorInService", "fifthRequest");
incomingCalls.stream().forEach(this::incomingCallsEgHttpCalls);
}
public void incomingCallsEgHttpCalls(String string) {
Observable.just(string)
.map(aName -> new BeanA(aName))
.doOnNext(bean -> eventBus.post(new CreateCommand(bean)))
.subscribe(bean -> System.out.println("\tReturn ok to client: " + bean.getName()), error -> System.out.println("\tReturning error to client: " + string + "; " + error.getMessage()));
}
public void handleBeanAInService1(BeanA beanA) {
System.out.println("BeanAService1 handling BeanA " + beanA.getName());
if(beanA.getName().contains("ErrorInService")) {
throw new RuntimeException("service exception for " + beanA.getName());
}
eventBus.post(new CreateCommand(new BeanB(beanA.getName())));
}
public void handleBeanAInService2(BeanA beanA) {
System.out.println("BeanAService2 handling BeanA " + beanA.getName());
}
public void handleBeanBInService(BeanB beanB) {
System.out.println("BeanBService handling BeanB " + beanB.getName());
}
}
EventBus
@Named
public class EventBus {
private PublishSubject<Object> publishSubject = PublishSubject.create();
public EventBus post(Object object) {
//publishSubject.onNext(object); => does not work, OnErrorNotImplementedExceptions if eventbus observers throw errors in validate
//To prevent OnErrorNotImplementedException
try {
publishSubject.onNext(object);
} catch (OnErrorNotImplementedException e) {
Throwable cause = e.getCause();
if (cause instanceof RuntimeException) {
throw (RuntimeException) cause;
}
throw new RuntimeException(cause);
}
return this;
}
public Observable<Object> observe() {
//I also tried
//return publishSubject.onErrorResumeNext(publishSubject);
return publishSubject;
}
public <F, T> Observable<T> on(Observable.Transformer<F, T> onCommand) {
return onCommand.call((Observable<F>) publishSubject);
}
}
CreateCommand
public class CreateCommand {
private Object object;
public CreateCommand(Object object) {
this.object = object;
}
public Class<?> type() {
return object.getClass();
}
public <T> T value() {
return (T) object;
}
public static <F, T> Observable.Transformer<F, T> createOf(Class<T> clazz) {
return observable -> observable
.ofType(CreateCommand.class)
.filter(createCommand -> clazz.isInstance(createCommand.object))
.map(createCommand -> clazz.cast(createCommand.object));
}
}
BeanA
public class BeanA {
private String name;
public BeanA(String name) {
this.name = name;
}
public String getName() {
return name;
}
public static void validateBusinessLogic(BeanA beanA) {
if (beanA.getName().contains("ErrorOnValidate")) {
throw new RuntimeException("validate exception for " + beanA.getName());
}
}
}
BeanB
public class BeanB {
private String name;
public BeanB(String name) {
this.name = name;
}
public String getName() {
return name;
}
}
实际输出
BeanAService1 handling BeanA firstRequest
BeanBService handling BeanB firstRequest
BeanAService2 handling BeanA firstRequest
Return ok to client: firstRequest
BeanAService1 handling BeanA secondRequestErrorOnValidate
BeanBService handling BeanB secondRequestErrorOnValidate
Returning error to client: secondRequestErrorOnValidate; validate exception for secondRequestErrorOnValidate
BeanAService1 handling BeanA thirdRequest
BeanBService handling BeanB thirdRequest
Return ok to client: thirdRequest
BeanAService1 handling BeanA fourthRequestErrorInService
Returning error to client: fourthRequestErrorInService; service exception for fourthRequestErrorInService
Return ok to client: fifthRequest
通缉输出
BeanAService1 handling BeanA firstRequest
BeanBService handling BeanB firstRequest
BeanAService2 handling BeanA firstRequest
Return ok to client: firstRequest
BeanAService1 handling BeanA secondRequestErrorOnValidate
BeanBService handling BeanB secondRequestErrorOnValidate
Returning error to client: secondRequestErrorOnValidate; validate exception for secondRequestErrorOnValidate
BeanAService1 handling BeanA thirdRequest
BeanBService handling BeanB thirdRequest
BeanAService2 handling BeanA thirdRequest
Return ok to client: thirdRequest
BeanAService1 handling BeanA fourthRequestErrorInService
BeanAService2 handling BeanA fourthRequestErrorInService
Returning error to client: fourthRequestErrorInService; service exception for fourthRequestErrorInService
BeanAService1 handling BeanA fifthRequest
BeanBService handling BeanB fifthRequest
BeanAService2 handling BeanA fifthRequest
Return ok to client: fifthRequest
任何想法如何解决？我看到rxjava中有关于EventBus实现的例子但是没有找到它的问题。
我也希望我的服务不需要做一些特定的rxjava错误处理。
或者是否有另一种方法将事件推送到多个其他可观察对象然后再次压缩结果？
答案 0 :(得分：1)
RxJava中的错误是拆除可观察流的终端事件（除非由onErrorXXX和onException运算符捕获/恢复）。如果要保持流存活，则需要将错误包装成其他值类型（即通知）并在相关位置打开它。
Here is an example gist显示了对RxJava构造的eventbus实现。请注意以下事项：