Marks a method as a handler for a client side event. The handler method will be invoked when a component triggers an
event. Filters on the type of event and on the originating component ensure that only the appropriate methods are
Client events include a context
of one or more values. These context values are included in the action URI.
The values are optionally supplied to the handler method as parameters. Automatic conversion
from string to the type of the actual parameter occur.
Handlers may return a value. Returning a non-null value will abort the handling of the event, and will usually
control the response sent to the client web browser. The details are somewhat specific to the type of event and the
If a handler is not found within the originating component (or no handler aborts the event handling), then handlers
within the containing component will be searched. This continues up the page hierarchy. In some cases, having no
handlers (or no aborting handlers) is considered acceptible; in others, it is an error. Again, this is defined by the
type of originating component, and the type of event.
If you fail to provide filters on either component or event type, then your method will be invoked for all
component events, possibly including events that bubble up from embedded sub-components.