I am, but your post is too long to read :) For what I understood, I had a similar problem, and I solved it encapsulating the "create widgetC" in a DeferredCommand (for your example).
Its really hard for me to understand the modification you purpose, maybe someone from google could see it. But I think that if you found a better way of doing something you should send a patch and make us all happy http://code.google.com/webtoolkit/makinggwtbetter.html (also you will get more help in gwt-code-reviews.appspot.com than here) Regards! // on the WidgetA.EventType reception is decided to create a widget C create widgetC On Tue, Jul 26, 2011 at 5:11 PM, david.herv...@gmail.com < david.herv...@gmail.com> wrote: > No body concerned ? > > On 25 juil, 10:50, "david.herv...@gmail.com" <david.herv...@gmail.com> > wrote: > > Hi, > > > > I'm facing a problem when using the simple implementation of the > > EventBus. > > > > // register widget B to be notified when WidgetA trigger an event > > register handler of WidgetB on WidgetA.EventType > > > > // dispatch (firingDepth is incremented) > > WidgetA.fireEvent > > > > // my widget is really called !!! that's good news > > WidgetB.onWidgetAEvent > > > > // on the WidgetA.EventType reception is decided to create a widget C > > create widgetC > > > > // this widget register himself to be notified on widgetB events -> > > here the widget is registered in the deferredDeltas map (enqueueing) > > register handler of widgetC on WidgetB.EventType > > > > // widget B fired an event which is never trapped by the widget C > > because the handler of Widget C is in the deferredDeltas AND > > firingDepth is not 0 > > WidgetB.fireEvent > > > > I'm doubtful because I was expected Widget C to receive event from > > Widget B. A work around is to encapsulate the WidgetB.fireEvent into a > > DeferredCommand but it's not really a solution. > > > > An other solution is to reconsider the usage of firingDepth, I don't > > really know why it is used (actually I know, but avoid concurrency > > modification that way leads to the upper that strange behavior). > > In simple implementation (thread safe) will be to get rid of the usage > > of this firingDepth/deferredDeltas and that getHandlerList return a > > copy of the handlers to go through and that's it: > > We insert directly the handler when they request for registration and > > we fire on the current map of handlers > > > > Below is a possible implementation of what I think is a better > > implementation (behaviorally speaking) : > > > > package com.google.web.bindery.event.shared; > > > > import java.util.ArrayList; > > import java.util.Collections; > > import java.util.HashMap; > > import java.util.HashSet; > > import java.util.List; > > import java.util.ListIterator; > > import java.util.Map; > > import java.util.Set; > > > > import com.google.web.bindery.event.shared.Event.Type; > > > > public class MySimpleEventBus extends EventBus { > > > > private final boolean isReverseOrder; > > > > /** > > * Map of event type to map of event source to list of their > > handlers. > > */ > > private final Map<Event.Type<?>, Map<Object, List<?>>> map = > > new HashMap<Event.Type<?>, Map<Object, List<?>>>(); > > > > public MySimpleEventBus() { > > this(false); > > } > > > > /** > > * Allows creation of an instance that fires its handlers in the > > reverse of > > * the order in which they were added, although filtered handlers > > all fire > > * before unfiltered handlers. > > * <p> > > * > > * @deprecated This is a legacy feature, required by GWT's old > > HandlerManager. > > * Reverse order is not honored for handlers tied to a > > specific > > * event source (via {@link #addHandlerToSource}. > > */ > > @Deprecated > > protected MySimpleEventBus(boolean fireInReverseOrder) { > > isReverseOrder = fireInReverseOrder; > > } > > > > @Override > > public <H> HandlerRegistration addHandler(Type<H> type, H handler) > > { > > return doAdd(type, null, handler); > > } > > > > @Override > > public <H> HandlerRegistration addHandlerToSource(final > > Event.Type<H> type, final Object source, > > final H handler) { > > if (source == null) { > > throw new NullPointerException("Cannot add a handler with a > > null source"); > > } > > > > return doAdd(type, source, handler); > > } > > > > @Override > > public void fireEvent(Event<?> event) { > > doFire(event, null); > > } > > > > @Override > > public void fireEventFromSource(Event<?> event, Object source) { > > if (source == null) { > > throw new NullPointerException("Cannot fire from a null > > source"); > > } > > doFire(event, source); > > } > > > > /** > > * @deprecated required by legacy features in GWT's old > > HandlerManager > > */ > > @Deprecated > > protected <H> void doRemove(Event.Type<H> type, Object source, H > > handler) { > > doRemoveNow(type, source, handler); > > } > > > > /** > > * @deprecated required by legacy features in GWT's old > > HandlerManager > > */ > > @Deprecated > > protected <H> H getHandler(Event.Type<H> type, int index) { > > assert index < getHandlerCount(type) : "handlers for " + > > type.getClass() + " have size: " > > + getHandlerCount(type) + " so do not have a handler at > > index: " + index; > > > > List<H> l = getHandlerList(type, null); > > return l.get(index); > > } > > > > /** > > * @deprecated required by legacy features in GWT's old > > HandlerManager > > */ > > @Deprecated > > protected int getHandlerCount(Event.Type<?> eventKey) { > > return getHandlerList(eventKey, null).size(); > > } > > > > /** > > * @deprecated required by legacy features in GWT's old > > HandlerManager > > */ > > @Deprecated > > protected boolean isEventHandled(Event.Type<?> eventKey) { > > return map.containsKey(eventKey); > > } > > > > private <H> HandlerRegistration doAdd(final Event.Type<H> type, > > final Object source, > > final H handler) { > > if (type == null) { > > throw new NullPointerException("Cannot add a handler with a > > null type"); > > } > > if (handler == null) { > > throw new NullPointerException("Cannot add a null handler"); > > } > > > > doAddNow(type, source, handler); > > > > return new HandlerRegistration() { > > public void removeHandler() { > > doRemove(type, source, handler); > > } > > }; > > } > > > > private <H> void doAddNow(Event.Type<H> type, Object source, H > > handler) { > > List<H> l = ensureHandlerList(type, source); > > l.add(handler); > > } > > > > private <H> void doFire(Event<H> event, Object source) { > > if (event == null) { > > throw new NullPointerException("Cannot fire null event"); > > } > > try { > > > > if (source != null) { > > event.setSource(source); > > } > > > > List<H> handlers = getDispatchList(event.getAssociatedType(), > > source); > > Set<Throwable> causes = null; > > > > ListIterator<H> it = > > isReverseOrder ? handlers.listIterator(handlers.size()) : > > handlers.listIterator(); > > while (isReverseOrder ? it.hasPrevious() : it.hasNext()) { > > H handler = isReverseOrder ? it.previous() : it.next(); > > > > try { > > event.dispatch(handler); > > } catch (Throwable e) { > > if (causes == null) { > > causes = new HashSet<Throwable>(); > > } > > causes.add(e); > > } > > } > > > > if (causes != null) { > > throw new UmbrellaException(causes); > > } > > } finally { > > // no more to do > > } > > } > > > > private <H> void doRemoveNow(Event.Type<H> type, Object source, H > > handler) { > > List<H> l = getHandlerList(type, source); > > > > boolean removed = l.remove(handler); > > assert removed : "redundant remove call"; > > if (removed && l.isEmpty()) { > > prune(type, source); > > } > > } > > > > private <H> List<H> ensureHandlerList(Event.Type<H> type, Object > > source) { > > Map<Object, List<?>> sourceMap = map.get(type); > > if (sourceMap == null) { > > sourceMap = new HashMap<Object, List<?>>(); > > map.put(type, sourceMap); > > } > > > > // safe, we control the puts. > > @SuppressWarnings("unchecked") > > List<H> handlers = (List<H>) sourceMap.get(source); > > if (handlers == null) { > > handlers = new ArrayList<H>(); > > sourceMap.put(source, handlers); > > } > > > > return handlers; > > } > > > > /** > > * Return a copy of handlers to dispatch event to > > */ > > private <H> List<H> getDispatchList(Event.Type<H> type, Object > > source) { > > List<H> directHandlers = getHandlerList(type, source); > > if (source == null) { > > return new ArrayList<H>(directHandlers); > > } > > > > List<H> globalHandlers = getHandlerList(type, null); > > > > List<H> rtn = new ArrayList<H>(directHandlers); > > rtn.addAll(globalHandlers); > > return rtn; > > } > > > > private <H> List<H> getHandlerList(Event.Type<H> type, Object > > source) { > > Map<Object, List<?>> sourceMap = map.get(type); > > if (sourceMap == null) { > > return Collections.emptyList(); > > } > > > > // safe, we control the puts. > > @SuppressWarnings("unchecked") > > List<H> handlers = (List<H>) sourceMap.get(source); > > if (handlers == null) { > > return Collections.emptyList(); > > } > > > > return handlers; > > } > > > > private void prune(Event.Type<?> type, Object source) { > > Map<Object, List<?>> sourceMap = map.get(type); > > > > List<?> pruned = sourceMap.remove(source); > > > > assert pruned != null : "Can't prune what wasn't there"; > > assert pruned.isEmpty() : "Pruned unempty list!"; > > > > if (sourceMap.isEmpty()) { > > map.remove(type); > > } > > } > > > > } > > -- > You received this message because you are subscribed to the Google Groups > "Google Web Toolkit" group. > 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. > > -- Guit: Elegant, beautiful, modular and *production ready* gwt applications. http://code.google.com/p/guit/ -- You received this message because you are subscribed to the Google Groups "Google Web Toolkit" group. 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