Post on 07-Apr-2015
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Classic Mistakes with Oracle Application Development Framework Internal APIs
Duncan Mills, Frank NimphiusOracle Application Development ToolsProduct Management
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Oracle Fusion Middleware
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To err is human and every developer has the right to make mistakes.
Don't abuse this privilege !
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ADF Framework Mistakes
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Using Internal Packages
• ADF Faces, Trinidad and ADF Controller have an API package and an IMPL package– Define logical framework abstractions– Simplifies implementation of future product changes
• APIs in public packages– guaranteed to remain stable from release to release
• APIs in IMPL package are internal-only – Not to be used outside of framework– Can be modified at any time without notice
• Internal packages have "internal" in the naming
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Binding Classes – The Java in ADF
FacesCtrl* Bindings
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FacesCtrlHierBinding
FacesCtrlHierBinding binding expose the convenient methods I need. My expert tip: Always use these classes
<af:table value="#{bindings.allLocations.collectionModel}" selectionListener="#{myBean.onTableSelect}"/>
public void onTableSelect(SelectionEvent selectionEvent) {
// --- perform optional pre-processing here --- //
RichTable _table = (RichTable ) selectionEvent.getSource();
CollectionModel model = (CollectionModel ) _table.getValue();
FacesCtrlHierBinding _binding = (FacesCtrlHierBinding) model.getWrappedData();
FacesCtrlHierBinding.FacesModel treeModel =
(FacesCtrlHierBinding.FacesModel) _binding.getTreeModel();
treeModel.makeCurrent(selectionEvent);
// --- perform optional post-processing here --- //}
Example(s)
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FacesCtrlHierBinding
• Don't use FacesCtrlHierBinding and FacesCtrlHierNodeBinding directly– Internal ADF Faces component model for tree, table and treeTable
• Use EL in Java: #{bindings.allDepartments.treeModel.makeCurrent}– Pro:
• Easy to use• Does it right for all Data Control types
– Con: • Requires knowledge about the PageDef definition
• Use JUCtrlHierBinding, JUCtrlHierNodeBinding– Pro:
• No knowledge about binding layer required– Con:
• More code to write• Requires advanced ADF skills
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Replacing FacesCtrlHierBinding
How-to use JUCtrlHierBinding to make the selected table row the current row in the ADF Binding
public void onTableSelect(SelectionEvent selectionEvent) { // --- perform optional pre-processing here --- //
RichTable _table = (RichTable ) selectionEvent.getSource(); CollectionModel model = (CollectionModel ) _table.getValue(); JUCtrlHierBinding _binding = (JUCtrlHierBinding) model.getWrappedData(); DCIteratorBinding iteratorBinding = _binding.getDCIteratorBinding(); Object _selectedRowData = _table´.getSelectedRowData(); JUCtrlHierNodeBinding node = (JUCtrlHierNodeBinding) _selectedRowData ; Key rwKey = node.getRowKey(); iteratorBinding.setCurrentRowWithKey(rwKey.toStringFormat(true));
// --- perform optional post-processing here --- //}
Example(s)
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Other Mistakes
• Unnecessary casting to Faces binding classes– the reference to Faces Binding object is obtained while
invoking non-faces specific binding methods. – In this case, replaced FacesCtrl* binding with JUCtrl* binding
• Caching as member variables – Faces binding reference as member variable, exposing public
getter and setter methods– In general, don't cache the binding reference
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ADF Bindings Mistakes
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#{data.} Expression Root
I can use the #{data…} root in my EL to pull information from another Binding Container!
<af:outputText value="#{data.demo_v1PageDef.LastName}"/>
public static ApplicationModule getApplicationModuleForDataControl(String name){
return(ApplicationModule)JSFUtils.resolveExpression( "#{data." + name + ".dataProvider}");
}
Example(s)
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#{data.} Expression Root
• Sorry – not reliable, may not always work– #{data.} accesses the binding cache and may not work if• You’ve never instantiated that binding container• You’ve just had a fail-over on a cluster• Plus it’s sloppy design – if the UI needs the data, then say
so!
• Safer approach– Create an explicit binding in the relevant pageDef and use #{bindings.*}
– In the finding the AM case, use an Action Binding• findCtrlBinding() getDataControl() getDataProvider()
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Accessing the "bindings" object using EL
I access the ADF binding layer from EL in Java, using #{bindings} . Objections ?
FacesContext fctx = FacesContext.getCurrentInstance();
ELContext elctx = fctx.getELContext();
Application app = fctx.getApplication();
ExpressionFactory efactory = app.getExpressionFactory();
ValueExpression vex = efactory.createValueExpression(
elctx,"#{bindings}", Object.class);
DCBindingContainer bindings = (DCBindingContainer) vex.getValue(elctx);
Example(s)
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Accessing the "bindings" object using EL
• Yes your honor – objection !• You can use Java instead of EL (things have moved
on)
BindingContext bindingContext = BindingContext.getCurrent();
BindingContainer bindings = bindingContext.getCurrentBindingsEntry();
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Using page fragments
Adding a page fragment to my ADF page does not render the ADF bound data content
<af:document id="d1">
...
<f:subview id="sv1">
<jsp:include page="/allDepartments.jsff"/>
</f:subview>
...
</af:document>
Example(s)
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Using page fragments
• JSP include only include the page content, not the ADF binding dependency• Suggestions– Copy the page fragment PageDef content into the PageDef
file of the parent page– Use ADF Faces page templates if the content you include is
used on many pages• Templates can have bindings
– Use ADF Regions• Bounded task flows• Can have their own bindings
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Adding new Rows
ADF bound table does not show new rows created in View Object
BindingContext bctx = BindingContext.getCurrent();
DCDataControl dc = bctx.findDataControl("AppModuleLocal");
ApplicationModule am = (ApplicationModule)dc.getDataProvider();
ViewObject vo = am.findViewObject("EmployeesVO1");
Row rw = vo.createRow();
rw.setAttribute("EmployeeId", 1234);
…
Example(s)
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Don't fight the framework !
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Adding new Rows
• You almost created a mine field!– Ignoring separation of layers– Bypassing the ADF binding layer– Making assumptions about the Data Control provider– Ignoring our message of what ADF is designed for
• Try working through the ADF binding layer
BindingContext bctx = BindingContext.getCurrentInstance();BindingContainer bindings = bctx.getCurrentBindingEntry()DCIteratorBinding dcIterator = (DCIteratorBinding) bindings.get("IteratorBindingName");Row rw = dcIteratorBinding.getRowSetIterator().createRow();rw.setNewRowState(Row.STATUS_INITIALIZED);
//insert row to iteratordcIteratorBinding.getRowSetIterator().insertRow(rw);
//make new row the currentdcIteratorBinding.setCurrentRowWithKey( rw.getKey().toStringFormat(true));
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Adding new Rows
• Better– if you have access to a table, tree or treeTable component– Does not require knowledge about the binding layer, thus generic
private void createRowInTable(RichTable table){
CollectionModel model = (CollectionModel ) table.getValue();
JUCtrlHierBinding _binding = (JUCtrlHierBinding) model.getWrappedData();
DCIteratorBinding dcIteratorBinding= _binding.getDCIteratorBinding();
Row rw = dcIteratorBinding.getRowSetIterator().createRow();
rw.setNewRowState(Row.STATUS_INITIALIZED);
//insert row to iterator dcIteratorBinding.getRowSetIterator().insertRow(rw);
//make new row the current
Key k = rw.getKey();
dcIteratorBinding.setCurrentRowWithKey(k.toStringFormat(true));
}
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ADF Controller Mistakes
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Task Flow Parameters
I used the expression editor to reference my Task Flow parameter… But it’s always NULL?
<input-parameter-definition> <name>arg</name> <value> #{pageFlowScope.myArg} </value> <class> java.lang.String </class> <required/></input-parameter-definition>
Example
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Task Flow Parameters
• Don’t be fooled by the expression editor!– In this circumstance it can’t quite be trusted.
• By setting the <value> attribute of the param-def you have re-mapped the data from the implied variable• Probably a good idea to explicitly
define a target bean in the task flow definition
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PageFlow scope has Stale Data
PageFlow scope returns old data. Is there a way to refresh the page flow scope ?
private Map<String, Object> scopeVar =
AdfFacesContext.getCurrentInstance().getPageFlowScope();
public void buttonAction() {
//the data read below is "old" !!!
Object param1Value = scopeVar.get("param1");
...
}
Example
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PageFlow scope has Stale Data
• Never store a scope map in a member variable of your bean• It does not improve performance and you might be
looking at stale data
public void buttonAction(ActionEvent ae) {
AdfFacesContext facesCtx = null;
facesCtx = AdfFacesContext.getCurrentInstance()
Map<String, Object> scopeVar = facesCtx.getPageFlowScope();
Object param1Value = scopeVar.get("param1"); ... }
Better
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PageFlow scope has Stale Data
• This also applies for other scopes
ADFContext.getCurrent().getApplicationScope();
ADFContext.getCurrent().getSessionScope();
AdfFacesContext.getCurrentInstance().getPageFlowScope();
ADFContext.getCurrent().getRequestScope();
ADFContext.getCurrent().getViewScope();
How-to access memory scope data in ADF
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"We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil"
- Donald Knuth
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Extending AdfcExceptionHandler
I extended the ADFc exception handler, creating oracle.adf. view.rich.context.ExceptionHandler configuration file in .adf/META-DATA/services
public class MyExceptionHandler extends AdfcExceptionHandler{
public void handleException(FacesContext facesContext, Throwable throwable, PhaseId pahseId){ String error = throwable.getMessage(); ...
super.handleException(...);
}
}
Example(s)
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Extending AdfcExceptionHandler
• Ouch ! Hold on ....• ADFc exception handling usually is sufficient and you
don't need to customize the exception handler– Not all exceptions are accessible for the ADFc controller
• If you need to extend the default exception handler– Don't use AdfcExceptionHandler – Internal class that you should not use– Even Product Managers got this wrong
• Extend ExceptionHandler and re-throw exceptions you don't know how to handle• See next slide how to do it right ...
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Extending AdfcExceptionHandler …
import oracle.adf.view.rich.context.ExceptionHandler; public class CustomExceptionHandler extends ExceptionHandler { public CustomExceptionHandler() { super(); } public void handleException(FacesContext facesContext, Throwable throwable, PhaseId phaseId) throws Throwable { String error_message; error_message = throwable.getMessage(); if (error_message != null && error_message.indexOf("ADF_FACES-30108") > -1) { ExternalContext ectx = facesContext.getExternalContext(); ectx.redirect("faces/SessionExpired.jspx"); } else { throw throwable; } }}
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Extending AdfcExceptionHandler
• Configuration– Create oracle.adf.view.rich.context.Exceptionhandler
text file and store it in .adf\META-INF\services – you need to create the “services” folder– Add the absolute name of your custom exception handler • Java class that extends ExceptionHandler
• Configuration is framework wide– Not to be deployed with ADF Library
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queueActionEventInRegion
If it bends, bend it! I found a cool way to execute ADF bindings contained in an ADF Region – Feeling lucky today.
richRegion.queueActionEventInRegion(
"#{bindings.Delete.execute}",
null,
null,
false,
0,
0, PhaseId.INVOKE_APPLICATION); }
Example(s)
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queueActionEventInRegion
public void queueActionEventInRegion(
javax.el.MethodExpression actionExpression,
javax.el.MethodExpression launchListenerMethodExpression,
javax.el.MethodExpression returnListenerMethodExpression,
java.lang.Boolean useWindow,
java.lang.Integer windowWidth,
java.lang.Integer windowHeight,
javax.faces.event.PhaseId phaseId
)
See here ...
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“I don't care about what anything was DESIGNED to do, I care about what it CAN do.”
Gene Kranz, Apollo 13 (Movie, 1995)
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queueAction
• Queues an ActionEvent so that it behaves as if you queued it on a command component inside of the region– Used to navigate region from outside– Navigation cases are discoverable
• Though executes any method, it is not what this is designed for– Available actions are not discoverable– Result of method invocation may not display– Works against TaskFlow encapsulation
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Product Demonstration
queueActionEventInRegion
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Redirect to Current Page
My page needs to redirect to current page. Using JSF ExternalContext redirect() works but seems to loose ADF controller state
FacesContext fctx = FacesContext.getCurrentInstance():
ExternalContext ectx = fctx.getExternalContext();
UIViewRoot root = fctx.getViewRoot();
String viewId = root.getViewId();
ectx.redirect("/faces/"+viewId);
Example
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Redirect to Current Page
• JSF doesn't know about ADF Controller and ADF Region states• Use ControllerContext to create redirect URL
private void redirectToSelf(){
FacesContext fctx = FacesContext.getCurrentInstance();
ExternalContext ectx = fctx.getExternalContext();
String viewId = fctx.getViewRoot().getViewId();
ControllerContext controllerCtx = null;
controllerCtx = ControllerContext.getInstance();
String activityURL = controllerCtx.getGlobalViewActivityURL(viewId);
try{
ectx.redirect(activityURL);
} catch (IOException e) {
//Can't redirect
e.printStackTrace();
}
}
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Navigation in Bounded Task Flow
JSF NavigationHandler.handleNavigation() is not recommended for use to navigate in bounded task flows though it appears to work. Why ? And what should I use instead ?
FacesContext fctx = FacesContext.getCurrentInstance();
NavigationHandler nh =
fctx.getApplication().getNavigationHandler();
nh.handleNavigation(fctx, null, "doEmployeesFiltered");
Example
Navigation case
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Navigation in Bounded Task Flow
• Let's do the "why" first– Directly invocation of methods on the NavigationHandler
doesn't conform with JSF specification• Bypasses JSF lifecycle– invoke application phase is missed out– Pending changes are not submitted– E.g, using ADF, no MDS commit would happen
• It's a bad thing to do even if you don't notice incorrect behavior
– The specification assumes that the framework will invoke the NavigationHandler in response to an ActionEvent
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Navigation in Bounded Task Flow
• I have a several options for you – 1. Use setViewId() on the controller context• Navigates to viewId in bounded task flow• Does not navigate to routers and method call activities
– 2. queue an action event on a command component– 3. Use queueActionEventOnRegion
ControllerContext ccontext = ControllerContext.getInstance();
//set the viewId to display
String viewId = "EmployeesView";
ccontext.getCurrentViewPort().setViewId(viewId);
Example
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Navigation in Bounded Task Flow
• A several options for you – 1. Use setViewId() on the controller context– 2. queue an action event on a command component• Component can be hidden
– 3. Use queueActionEventOnRegion
private void onQueueC3ButtontAction() {
FacesContext fctx = FacesContext.getCurrentInstance();
UIViewRoot root = fctx.getViewRoot();
RichCommandButton button =
(RichCommandButton) root.findComponent("r1:cb3");
ActionEvent actionEvent = new ActionEvent(button);
actionEvent.queue();
}
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Navigation in Bounded Task Flow
• A couple of options for you – 1. Use setViewId() on the controller context– 2. queue an action event on a command component– 3. Use queueActionEventOnRegion• Queues an action by its navigation case
Private void navUsingQueueAction(ActionEvent actionEvent) {
UIComponent comp = actionEvent.getComponent();
while(!(comp instanceof RichRegion)){
comp = comp.getParent();
}
((RichRegion) comp).queueActionEventInRegion( createMethodExpressionFromString("doEmployees"), null, null, false, 0, 0,PhaseId.INVOKE_APPLICATION);
}
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Navigation in Bounded Task Flow
• Helper Method
private MethodExpression createMethodExpressionFromString(String s){
FacesContext fctx = FacesContext.getCurrentInstance();
ELContext elctx = fctx.getELContext();
ExpressionFactory exprFactory =
fctx.getApplication().getExpressionFactory();
MethodExpression methodExpr = exprFactory.createMethodExpression(
elctx,
s,
null,
new Class[]{});
return methodExpr;
}
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Product Demonstration
Navigation in bounded Task Flow
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Expression Language Mistakes
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Accessing Managed Beans #{requestScope.<…>}
I prefix all my managed bean EL references with the scope the bean is in, for example, #{requestScope. BeanName.propertyName}
<af:outputText value="#{requestScope.BeanName.LastName}"/>
Example(s)
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Accessing Managed Beans #{requestScope.<…>}
• Doesn’t always work for beans in default Servlet scopes– requestScope, sessionScope, applicationScope– Bypasses JavaServer Faces managed bean facility• Only looks for in-memory objects• Does not instantiate managed beans
– Only good idea if looking up memory attributes you know exist or you want to create
• Works for ADF specific scopes– viewScope, pageFlowScope, backingBeanScope– ADFc controller takes care of managed bean instantiation if
configuration is available
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JavaServer Faces Mistakes
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I have a command button that when pressed should update a text field. Just its not working … Arrrgs
<af:inputtext value="#{mybacking.firstName}" .../>
<af:commandButton action="#{mybacking.updateFirstNameVal}" immediate="true" .../>
Example(s)
JSF Lifecycle - immediate="true"
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JSF Lifecycle - immediate="true"
• Understand the JSF Request Lifecycle• JSF Phases
• Immediate means "execute first" not "execute only"– Command button is special case– Use "immediate" on button to bypass model update
Render Response
Restore View
Apply Request Values
Process Validation
Update Model Values
Invoke Application
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ADF Lifecycle "extends" JSF Lifecycle
Render Response
Restore View
Apply Request Values
Process Validation
Update Model Values
Invoke Application
ChangedView?
JSF Restore View
Init Context
Prepare Model
JSF Apply Request Values
JSF Process Validation
JSF Update Model Values
Validate Model Updates
JSF Invoke Applications
Meta Data Commit
yes
no
New
Context
Init Context
Prepare Model
Prepare Render
Prepare Render
For Same View
Render Response
For Same View
ADF Lifecycle PhasesJSF Lifecycle Phases
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Product Demonstration
Immediate = true
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One to Print on a T-Shirt
Immediate = true ≠ PartialSubmit = true
PartialSubmit = true ≠ Immediate = true
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ADF Faces Component Mistakes
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Mixing JSF and HTML
HTML helps me to create the layout I want. Sometimes however it seems to break ADF Faces. Is this a bug ?
<af:form>
<table>
<tr valign="top">
<td><af:inputText ... label="search" /></td>
<td><af:commandButton ... text="go" /></td>
</tr>
</table>
...
</af:form>
Example(s)
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Mixing JSF and HTML
• HTML only theoretically works in JSF– JSF 1.2 synchronizes lifecycle so that HTML "waits" for JSF– Not all components accept HTML as a child component– HTML binds to data using JSTL, which can only supports
deferred expressions ${ ... }
• ADF Faces RC layout component handle geometry management, which may conflict with HTML• ADF Faces components canbe accessed and
manipulated from managed beans• HTML elements don't participate in PPR• Recommendation: Don't mix and match !
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Examples
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Inline Style CSS
Some components seem to ignore CSS. Others apply it wrong
<af:inputText label="PhoneNumber" id="it2"
inlineStyle="background-color:Red; color:Green;"/>
Example(s)
????
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Inline Style CSS
<tbody><tr id="j_id_id16" <td> <label for="j_id_id16::content"> PhoneNumber </label> </td> <td> <input id="j_id_id16::content" type="text" value="650.507.9833"/> </td></tr></tbody>
=
• ADF Faces Components are far more complex than simple HTML elements
• Styles are applied to the root DOM element, not the component itself• ContentStyle styles the inner area of a component• Solution: Skinning
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Nesting Tables – Failed Use Case I
I want nested ADF Faces tables. This does not seem to work.
Example(s)
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Nesting Tables – Failed Use Case I
• Sample already optimized as much as possible– Its as good as it gets– Used tree binding for m/d to work (!)– Auto row sizing to trim table layout– Still, not a good idea– Messes with ADF Faces geometry management
No layout boundaries
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Not everything that compiles can be shipped!
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af:forEach, af:iterator
• af:forEach and af:Iterator tags are often confused• af:Iterator– Behaves like a table without chrome– Stamps children– Can be used with JSF DataModel and Trinidad
CollectionModel– Child items can access EL variables defined on a parent• e.g. "row" in a table
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af:forEach, af:iterator
• af:forEach– Replaces JSTL c:forEach, which does not support varStatus– Only iterates java.util.Lists
• Does not support java.util.Collection
– Use to generate components• For example: <f:selectItem …>• Components are remembered by their index
– items created by <af:forEach> should not be added, removed or re-ordered once the component tree has been created
– Use cases• Components should be created conditionally based item in the loop. • Different JSP includes, page templates, and dynamic declarative
components should be included per loop iteration
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Nesting Tables – Failed Use Case II
Need help! I am trying to build a nested table. Doesn't work in ADF Faces. Must be a bug. Screw you Oracle !
<af:table … value="#{bindings.allDepartments.collectionModel}">
...
<af:column>
<af:table ... Value="#{bindings.dependentEmployees.collectionModel">
...
</af:table>
</af:column>
</af:table>
Example(s)
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Nesting Tables
• Tables are rendered on the server– Valid children is af:column• Valid children are any output component and layout
element– Tables are stamped, which means that a row is not a new
instance of a component• No single table row refresh• No query issued to fetch m/d dependent data per row
– If nested layouts are needed, use af:forEach or afIterator
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af:iterator in table columns
My table rows have nested information I want to show to users. How do I do this then ?
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af:iterator in table columns
• Create a detail node binding• Use #{row.children} in af:iterator
Var="row"
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Opening popup dialogs
I want to open a popup from a command link in a table using af:showPopupBehavior. The popup does not show and instead the page is refreshed
<af:commandButton text="commandButton 1" id="cb1">
<af:showPopupBehavior popupId="popup1"
triggerType="action"
align="afterEnd"
alignId="it1"/>
</af:commandButton>
<af:popup id="popup1" ...>
...
</af:popup>
Example(s)
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Opening popup dialogs
• Popups must be opened using a partial submit• Its a lighweight dialog that is part of the page HTML
output– Repainting the page closes the popup
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File Upload in ADF Region
• Same code works in JSPX page• I see no exception
File uploads don't work in ADF Regions. I am scratching my head in disbelief
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File Upload in ADF Region
• ADF Region uses page fragments• Page fragments don't have an af:form tag on their
own• af:form tag is in parent page, or if parent page is
fragment too, in the parent's parent page• Make sure af:form tag has usesUpload="true" set
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JavaScript Mistakes
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Using the Browser DOM
I am a JavaScript expert and "DOM" is my corporate nickname.: DOM, James DOM
function cancelEventAndUpdateWithDom(evt){
evt.cancel();
var txtfield1 = document.getElementById("it1::content");
txtfield1.value = "Hello OOW 2010"
}
Example(s)
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Using the Browser DOM
• Accessing the browser DOM operates on HTML markup– Markup is generated by component renderers – HTML output may change without notice as it is an implementation
detail of the JSF component renderer– HTML markup does not • provide same set of component properties• Allow PPR
• Better– If you need to use JavaScript, use the ADF Faces client frameworkfunction cancelEventAndUpdateWithAdfFaces(evt){
evt.cancel();
var txtfield1 = AdfPage.PAGE.findComponentByAbsoluteId('it1');
txtfield1.setValue("Hello OOW 2010");
}
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Using the Browser DOM
Tried what you said – just doesn't work. Back to direct DOM manipulation ?
var txtfield1 = AdfPage.PAGE.findComponentByAbsoluteId('it1');
Example(s)
Always returns null
<af:inputText id="it1" value="#{SampleBean.txt1}"/>
<af:commandButton text="Update" id="cb1" partialSubmit="true">
<af:clientListener method="cancelEventAndUpdateWithAdfFaces"
type="action"/>
</af:commandButton>
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Using the Browser DOM
• ADF Faces is performance optimized– Most of the components rendered byserver side generated HTML
markup– JavaScript objects are created for components with rich functionality– Developers can enforce JavaScript object to be rendered• Setting component property clientComponent = "true" or ...• ... apply clientListener
<af:inputText id="it1" value="#{SampleBean.txt1}"
clientComponent="true"/>
<af:commandButton text="Update" id="cb1" partialSubmit="true">
<af:clientListener method="cancelEventAndUpdateWithAdfFaces"
type="action"/>
</af:commandButton>
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Related Oracle Press Books
• Quick Start Guide to Oracle Fusion Development• Oracle JDeveloper 11g Handbook• Oracle Fusion Developer Guide