Log a warning when there are several ajax event behaviors on the same event

[Martin Grigorov]

Hi,

What do you think about this additional code in
AjaxEventBehavior#onComponentTag() (Wicket 1.5) :

@@ -108,6 +112,20 @@ public abstract class AjaxEventBehavior extends
AbstractDefaultAjaxBehavior
                Component myComponent = getComponent();
                if (myComponent.isEnabledInHierarchy())
                {
+                       if (LOG.isWarnEnabled() &&
myComponent.getApplication().usesDevelopmentConfig())
+                       {
+                               String attribute = tag.getAttribute(event);
+                               if (Strings.isEmpty(attribute) == false)
+                               {
+                                       LOG.warn("{} assigned to {} is
overriding the previous value of the inline attribute. " +
+                                               "Maybe there are
several Ajax event behaviors on the same type assigned to this
component."
+                                               new Object[] {
+                                                       this, myComponent
+                                               }
+                                       );
+                               }
+                       }


The problem it tries to solve is that you can add several AEBs on the
same event type to a component and silently the last one wins.
This warning should tell the developer that something bad may happen

-- 
Martin Grigorov
jWeekend
Training, Consulting, Development
http://jWeekend.com