I have a
little problem to solve earlier this week - misbehaving <af:panelBox> components... What do I mean by that? Well here's
the scenario, I have a page fragment containing a set of panelBoxes arranged vertically. As it happens, they are stamped out in a loop but that does not really matter. What I want to be able to do is to provide
the user with a simple UI to close and open all of
the panelBoxes in concert. This could also apply to showDetailHeader and similar items with a disclosed attrubute, but in this case it's good old panelBoxes.
Ok, so
the basic solution to this should be self evident. I can set up a suitable scoped managed bean that
the panelBoxes all refer to for their disclosed attribute state. Then
the open all / close commandButtons in
the UI can simply set
the state of that bean for all
the panelBoxes to pick up via EL on their disclosed attribute. Sound OK? Well that works basically without a hitch, but turns out that there is a slight problem and this is where
the framework is attempting to be a
little too helpful.
The issue is that is
the user manually discloses or hides a panelBox then that will override
the value that
the EL is setting. So for example.
I start
the page with all panelBoxes collapsed, all set by
the EL state I'm storing on
the session
I manually disclose panelBox no 1.
I press
the Expand All button - all works as you would hope and all
the panelBoxes are now disclosed, including of course panelBox 1 which I just expanded manually.
Finally I press
the Collapse All button and everything collapses except that first panelBox that I manually disclosed.
The problem is that
the component remembers this manual disclosure and that overrides
the value provided by
the expression. If I change
the viewId (navigate away and back) then
the panelBox will start to behave again, until of course I touch it again! Now,
the more astute amoungst you would think (as I did) Ah, sound like
the MDS personalizaton stuff is getting in
the way and
the solution should simply be to set
the dontPersist attribute to disclosed | ALL. Alas this does not fix
the issue.
After a
little noodling on
the best way to approach this I came up with a solution that works well, although if you think of an alternative way do let me know.
The principle is simple. In
the disclosureListener for
the panelBox I take a note of
the clientID of
the panelBox component that has been touched by
the user along with
the state. This all gets stored in a Map of Booleans in ViewScope which is keyed by clientID and stores
the current disclosed state in
the Boolean value.
The listener looks like this (it's held in a request scope backing bean for
the page):
public void handlePBDisclosureEvent(DisclosureEvent disclosureEvent) {
String clientId = disclosureEvent.getComponent().getClientId(FacesContext.getCurrentInstance());
boolean state = disclosureEvent.isExpanded();
pbState.addTouchedPanelBox(clientId, state);
}
The pbState variable referenced here is a reference to
the bean which will hold
the state of
the panelBoxes that lives in viewScope (recall that everything is re-set when
the viewid is changed so keeping this in viewScope is just fine and cleans things up automatically).
The addTouchedPanelBox() method looks like this:
public void addTouchedPanelBox(String clientId, boolean state) {
//create
the cache if needed this is just a Map<String,Boolean>
if (_touchedPanelBoxState == null) {
_touchedPanelBoxState = new HashMap<String, Boolean>();
}
// Simply put / replace
_touchedPanelBoxState.put(clientId, state);
}
So that's
the first part, we now have a record of every panelBox that
the user has touched. So what do we do when
the Collapse All or Expand All buttons are pressed? Here we do some JavaScript magic. Basically for each clientID that we have stored away, we issue a client side disclosure event from JavaScript - just as if
the user had gone back and changed it manually.
So here's
the Collapse All button action:
public String CloseAllAction() {
submitDiscloseOverride(pbState.getTouchedClientIds(true), false);
_uiManager.closeAllBoxes();
return null;
}
The _uiManager.closeAllBoxes() method is just manipulating
the master-state that all of
the panelBoxes are bound to using EL.
The interesting bit though is
the line:
submitDiscloseOverride(pbState.getTouchedClientIds(true), false);
To break that down,
the first part is a call to that viewScoped state holder to ask for a list of clientIDs that need to be "tweaked":
public String getTouchedClientIds(boolean targetState) {
StringBuilder sb = new StringBuilder();
if (_touchedPanelBoxState != null && _touchedPanelBoxState.size() > 0) {
for (Map.Entry<String, Boolean> entry : _touchedPanelBoxState.entrySet()) {
if (entry.getValue() == targetState) {
if (sb.length() > 0) {
sb.append(',');
}
sb.append(entry.getKey());
}
}
}
return sb.toString();
}
You'll notice that this method only processes those panelBoxes that will be in
the wrong state and returns those as a comma separated list.
This is then processed by
the submitDiscloseOverride() method:
private void submitDiscloseOverride(String clientIdList, boolean targetDisclosureState) {
if (clientIdList != null && clientIdList.length() > 0) {
FacesContext fctx = FacesContext.getCurrentInstance();
StringBuilder script = new StringBuilder();
script.append("overrideDiscloseHandler('");
script.append(clientIdList);
script.append("',");
script.append(targetDisclosureState);
script.append(");");
Service.getRenderKitService(fctx, ExtendedRenderKitService.class).addScript(fctx, script.toString());
}
}
This method constructs a JavaScript command to call a routine called overrideDiscloseHandler() in a script attached to
the page (using
the standard <af:resource> tag). That method parses out
the list of clientIDs and sends
the correct message to each one:
function overrideDiscloseHandler(clientIdList, newState) {
AdfLogger.LOGGER.logMessage(AdfLogger.INFO, "Disclosure Hander newState " + newState + " Called with: " + clientIdList);
//Parse out
the list of clientIds
var clientIdArray = clientIdList.split(',');
for (var i = 0; i < clientIdArray.length; i++){
var panelBox = flipPanel = AdfPage.PAGE.findComponentByAbsoluteId(clientIdArray[i]);
if (panelBox.getComponentType() == "oracle.adf.RichPanelBox"){
panelBox.broadcast(new AdfDisclosureEvent(panelBox, newState));
}
}
}
So there you go. You can see how, with a few tweaks
the same code could be used for other components with disclosure that might suffer from
the same problem, although I'd point out that
the behavior I'm working around here us usually desirable.
You can download
the running example (11.1.2.2) from here.
