| org.wings.LowLevelEventListener
All known Subclasses: org.wings.STable, org.wings.SAbstractButton, org.wings.dnd.DragAndDropManager, org.wingx.XDivision, org.wings.SSplitPane, org.wings.SSpinner, org.wings.SForm, org.wingx.XColorPicker, org.wings.SWindow, org.wings.STree, org.wings.SFrame, org.wings.SSlider, org.wings.SAbstractAdjustable, org.wingx.XCalendar, org.wings.SComboBox, org.wings.STabbedPane, org.wings.SFileChooser, org.wings.STextComponent, org.wings.SInternalFrame, org.wings.SList,
| LowLevelEventListener | | public interface LowLevelEventListener (Code) | | For components that take part in the event dispatching process.
WingS event dispatching is complex. This is because we have to process many
requests at once (asynchronous user interaction). There are three levels of
dispatching:
- process http requests (
LowLevelEventListener.processLowLevelEvent ): If a component is
registered at the session specific
org.wings.session.LowLevelEventDispatcher it gets all the
parameters is is registered for. This parameter consists of a name-value
pair. Most time the component itself has encoded this parameter, so it is
able to decode it and change its internal state. This should be done in
LowLevelEventListener.processLowLevelEvent . Be careful, the change of the internal state shold
not trigger any events, because in case of a form request, many requests are
processed and many states of components are changed, so if you trigger an
event, the listener may access a component which has not yet processed its
request parameters and so it is in an inconsistent state.
- fire intermediate events: fire events which describes a "in progress"
state change, like TreeWillExpand, or ListSelectionEvent with
getIsAdjusting() true, ...
After this level are components must be in a consistant state
- fire final events: fire remaining events. In this level all events, which
are important to an application should be fired. All listeners, which are
notified in this level can assume that the components are in a consistent
(considering user interaction) state.
author:
Armin Haaf |
| Method Summary | |
| void | fireFinalEvents()
fire remaining events. | | void | fireIntermediateEvents()
fire events which describes a "in progress"
state change, like TreeWillExpand, or ListSelectionEvent with
getIsAdjusting() true, ... | | String | getLowLevelEventId()
The id of an event which will be forwarded by the dispatcher to this
component for processing. | | String | getName()
If the dispatcher is configured to use named event, the return value of
this method is used to identiy a LowLevelEventListener by name. | | boolean | isEnabled()
SCompontents are typically implemntors of this interface. | | boolean | isEpochCheckEnabled()
Asks the low-level event listener if epoch checking should be perfomed on it. | | void | processLowLevelEvent(String name, String[] values)
Deliver low level/http events (parameters). |
| fireFinalEvents | | void fireFinalEvents()(Code) | | fire remaining events. In this level all events, which
are important to an application should be fired. All listeners, which are
notified in this level can assume that the components are in a consistent
(considering user interaction) state.
|
| fireIntermediateEvents | | void fireIntermediateEvents()(Code) | | fire events which describes a "in progress"
state change, like TreeWillExpand, or ListSelectionEvent with
getIsAdjusting() true, ...
|
| getLowLevelEventId | | String getLowLevelEventId()(Code) | | The id of an event which will be forwarded by the dispatcher to this
component for processing. A component is registered at the
org.wings.session.LowLevelEventDispatcher dispatcher . This
dispatcher forwards servlet parameters (low level events) to each
LowLevelEventListener registered for this event. A LowLevelEventListener
is registered for an event, if the event id is equals to the result of
this method.
|
| getName | | String getName()(Code) | | If the dispatcher is configured to use named event, the return value of
this method is used to identiy a LowLevelEventListener by name. E.g. in a
http request you might give an action a special name, like
"ActivateUpload" to make uploads possible. This action is a SButton in
wings with the name "ActivateUpload" and an ActionListener which make the
upload form visible. A designer might call your servlet with
"servlet/_?ActivateUpload=1" to make the upload form visible by hand. Be
careful, this so called "Named Events" are not under control of wings, so
they will no be outtimed and might lead to strange effects.
|
| isEnabled | | boolean isEnabled()(Code) | | SCompontents are typically implemntors of this interface. No disabled component
should receive any event.
true, if LowLevelEventListener should be addressed |
| isEpochCheckEnabled | | boolean isEpochCheckEnabled()(Code) | | Asks the low-level event listener if epoch checking should be perfomed on it.
If true the Dispatcher will ignore request originating from old views
(typically iniated by triggering browser back and clicking somewhere.)
true if epoch checking should be perfomed, falseif all request for this component should be processed. |
| processLowLevelEvent | | void processLowLevelEvent(String name, String[] values)(Code) | | Deliver low level/http events (parameters).
The name-value-pairs of the HTTPRequest are considered low level events.
Parameters:
name - the name-value-pair's name
Parameters:
values - the name-value-pair's values |
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