Re: A static EventBus / SimpleEventBus: Pro Contra
Injecting an EventBus allows you to pass the one instance you want (SimpleEventBus, ResettableEventBus, CountingEventBus, RecordingEventBus, or your own subtype), and change that between dev, production, and tests. -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/x7AlvB4OuZkJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: A static EventBus / SimpleEventBus: Pro Contra
Maybe I've misguided you mentioning the SimpleEventBus implementation of
the EventBus interface. The actual question was whether I should use a
*static* EventBus that can be defined in a Common class and reference
this static EventBus from any other view.
E.g. using
*MyView() {*
*// MyView Constructor*
*}*
*
*
*Common.myEventBus.fireEvent(new MyEvent()); // the _static_ way*
VS.
*MyView(final EventBus myEventBus) {*
*this.myEventBus = myEventBus;*
*// The rest of MyView Constructor*
*}*
*
*
*myEventBus.fireEvent(new MyEvent()); // the _non-static_ way*
On Mon, Nov 7, 2011 at 12:15 PM, Thomas Broyer t.bro...@gmail.com wrote:
Injecting an EventBus allows you to pass the one instance you want
(SimpleEventBus, ResettableEventBus, CountingEventBus, RecordingEventBus,
or your own subtype), and change that between dev, production, and tests.
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Re: A static EventBus / SimpleEventBus: Pro Contra
I had understood, so that doesn't change my answer. With the static instance, everyone shares exactly the same. With an injected instance, you can wrap your global singleton eventbus within a ResettableEventBus in some cases (depending on how you manage your classes lifecycle), or some other custom similar eventbus, and/or you can pass a CountingEventBus or RecordingEventBus in your unit tests. -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/bRzvMXRuXEkJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: A static EventBus / SimpleEventBus: Pro Contra
As GIN also supports static injection it seems like there is not much of a difference, but: 1.) Using the static way you somehow hide the fact that a class depends on an event bus 2.) Sometimes its nice to have multiple instances of an event bus. Especially having multiple ResettableEventBus's are pretty handy that wrap that singleon app wide event bus. -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/T8SRhnObNAUJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: A static EventBus / SimpleEventBus: Pro Contra
Sorry if I didn't make it clear enough: With the static instance, everyone shares exactly the same [instance], which means that you cannot choose, for a particular object, to use a different instance (e.g. ResettableEventBus), unless you make that object depend explicitly on the other instance (in other words, this is a everyone *must* use the same instance, not a everyone uses the same instance by default). That means you're tightly coupling your objects with the eventbus, when you chose to use an EventBus in the first place to decouple your objects [sic]. (oh, and injecting doesn't necessarily mean GIN or a DI framework/tool ;-) ) -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/NukiqMbwIuMJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
Re: A static EventBus / SimpleEventBus: Pro Contra
Not that it's really what you asked (I agree with the replies you've
received), but if you're using the idiom shown in some of the Google
presentations/samples/vids, instead of direct references to the EventBus
instance (which is a class and not an interface ... I don't know why), you
may have something like this:
MyEvent.register(...);
MyEvent.fire(new MyEvent(...));
That's pretty convenient, but suffers from the same problem mentioned in
the other replies.
I've gone to something like this:
I inject/construct with instances of a class like MyEventBroker, which
looks like:
public class MyEventBroker {
EventBus eventBus;
public MyEventBroker(EventBus eventBus) { ... }
public HandlerRegistration registerEventOneHandler(...) { ... }
public void fireEventOne(EventOne eventOne) { ... }
public HandlerRegistration registerEventTwoHandler(...) { ... }
public void fireEventTwo(EventTwo eventTwo) { ... }
...
}
I used to have a lot of events, but since moving to MVP, I have far fewer.
Nevertheless, I find it convenient, while YMMV.
Anyway, most of my classes don't need direct references to EventBus
instances, just the MyEventBroker instance. I never liked the static
methods I saw in the Google samples. Statics always seem to bite me if I
am not careful, and messing with my testing seems to be one of the first
places.
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A static EventBus / SimpleEventBus: Pro Contra
EventBus is a really nice mechanism to *decouple methods from callbacks* by adding corresponding event handlers to an EventBus. By nature EventBus is something that should be known to both classes, the calling and the called class. So you can *1. pass an EventBus in a constructor or* *2. use a static EventBus that can be called from any View* Is there a rule of thumb how you should use an EventBus? So far I saw only constructor usage examples. Are there some significant disadvantages that come with a static EventBus? -- You received this message because you are subscribed to the Google Groups Google Web Toolkit group. To view this discussion on the web visit https://groups.google.com/d/msg/google-web-toolkit/-/1W_HXJS76-AJ. To post to this group, send email to google-web-toolkit@googlegroups.com. To unsubscribe from this group, send email to google-web-toolkit+unsubscr...@googlegroups.com. For more options, visit this group at http://groups.google.com/group/google-web-toolkit?hl=en.
