java Guava事件总线：不捕获RuntimeException

Question

我使用guava的EventBus，不幸的是它捕获并记录了事件处理程序抛出RuntimeException时发生的InvocationTargetException。我可以禁用此行为吗

Answer 1

这里是懒惰的代码

public class Events
{
    public static EventBus createWithExceptionDispatch()
    {
        final EventBus bus;

        MySubscriberExceptionHandler exceptionHandler = new MySubscriberExceptionHandler();
        bus = new EventBus(exceptionHandler);
        exceptionHandler.setBus(bus);
        return bus;
    }

    private static class MySubscriberExceptionHandler implements SubscriberExceptionHandler
    {
        @Setter
        EventBus bus;

        @Override
        public void handleException(Throwable exception, SubscriberExceptionContext context)
        {
            ExceptionEvent event = new ExceptionEvent(exception, context);
            bus.post(event);
        }
    }
}

现在，您可以订阅ExceptionEvent

这是我的ExceptionEvent，仅供复制&；粘贴

@Data
@Accessors(chain = true)
public class ExceptionEvent
{
    private final Throwable exception;
    private final SubscriberExceptionContext context;
    private final Object extra;

    public ExceptionEvent(Throwable exception)
    {
        this(exception, null);
    }

    public ExceptionEvent(Throwable exception, Object extra)
    {
        this(exception,null,extra);
    }

    public ExceptionEvent(Throwable exception, SubscriberExceptionContext context)
    {
        this(exception,context,null);
    }

    public ExceptionEvent(Throwable exception, SubscriberExceptionContext context, Object extra)
    {
        this.exception = exception;
        this.context = context;
        this.extra = extra;
    }
}

Answer 2

目前，这是一个经过深思熟虑的决定，并在EventBus文档中进行了讨论：

Handlers should not, in general, throw. If they do, the EventBus will catch and log the exception. This is rarely the right solution for error handling and should not be relied upon; it is intended solely to help find problems during development.

替代解决方案是being considered，尽管我严重怀疑它们能否进入第12版

Answer 3

只需继承guava EventBus，并编写自己的自定义EventBus。 提示：这个类应该用com编写。谷歌。常见的eventbus包，以便可以覆盖内部方法

package com.google.common.eventbus;

import com.google.common.util.concurrent.MoreExecutors;

public class CustomEventBus extends EventBus {

    /**
     * Creates a new EventBus with the given {@code identifier}.
     *
     * @param identifier a brief name for this bus, for logging purposes. Should be a valid Java
     *     identifier.
     */
    public CustomEventBus(String identifier) {
        super(
            identifier,
            MoreExecutors.directExecutor(),
            Dispatcher.perThreadDispatchQueue(),
            LoggingHandler.INSTANCE);
    }

    /**
     * Creates a new EventBus with the given {@link SubscriberExceptionHandler}.
     *
     * @param exceptionHandler Handler for subscriber exceptions.
     * @since 16.0
     */
    public CustomEventBus(SubscriberExceptionHandler exceptionHandler) {
        super(
            "default",
            MoreExecutors.directExecutor(),
            Dispatcher.perThreadDispatchQueue(),
            exceptionHandler);
    }

    @Override
    void handleSubscriberException(Throwable e, SubscriberExceptionContext context) {
        throw new EventHandleException(e);
    }
}