Understanding the JSF Immediate Attribute

As, i am working on my project.I have to use cancel button.So somebody said make immediate attribute to true.There is very common myth among ADF and JSF developers that using Immediate attribute will avoid unnecessary validation in any case. It is not 100% correct. Basically , everyone not very much clear about it. If we don’t use correctly , application can work randomly.Let discuss more about it to have better understanding.

In ADF application we have either

1. input component
2. Command component

You can use the immediate attribute to allow components on the page to be validated in the Apply Request Values phase of the life cycle as opposed to the Process Validations phase:

•Input component- Using immediate on an means that that component’s value is validated before any input components that do not have the immediate attribute set to true. Therefore, if a validation error occurs on an immediate input component, the life cycle moves from the Apply Request Values phase (where the immediate attribute is evaluated) to the render phase, and validation does not run on any “nonimmediate” input components. Additionally, if the new value of an immediate input component is different from the existing value, then a ValueChangeEvent is raised. However, instead of the event being processed during the Process Validations phase, the event is processed at the end of the Apply Request Values phase. Therefore, any ValueChangeListener associated with the immediate input component executes before any command component’s ActionListener (assuming the command component occurs later on the page).


• Command Components-
if set to immediate and the component has an action that
returns a value for navigation, the life cycle proceeds directly to the Render Response
phase. The validation and model update phases are skipped. A Cancel button is an example of when this would be used

ADF & JSF: Some handy code for backing beans

Following are the Some code which is very usefull when working in oracle ADF and JSF.Please go through


// print the roles of the current user
for ( String role : ADFContext.getCurrent().getSecurityContext().getUserRoles() ) {
System.out.println("role "+role);
}




// get the ADF security context and test if the user has the role users 
SecurityContext sec = ADFContext.getCurrent().getSecurityContext();
if ( sec.isUserInRole("users") ) {
}


// is the user valid
public boolean isAuthenticated() {
return ADFContext.getCurrent().getSecurityContext().isAuthenticated();
}



// return the user 
public String getCurrentUser() {
return ADFContext.getCurrent().getSecurityContext().getUserName();
}



// get the binding container 
BindingContainer bindings = BindingContext.getCurrent().getCurrentBindingsEntry();



// get an ADF attributevalue from the ADF page definitions 
AttributeBinding attr = (AttributeBinding)bindings.getControlBinding("test");
attr.setInputValue("test");



// get an Action or MethodAction 
OperationBinding method = bindings.getOperationBinding("methodAction");
method.execute();
List errors = method.getErrors();



method = bindings.getOperationBinding("methodAction");
Map paramsMap = method.getParamsMap();
paramsMap.put("param","value") ;
method.execute();



// Get the data from an ADF tree or table
DCBindingContainer dcBindings = (DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry();

FacesCtrlHierBinding treeData = (FacesCtrlHierBinding)bc.getControlBinding("tree");
Row[] rows = treeData.getAllRowsInRange();



// Get a attribute value of the current row of iterator 
DCIteratorBinding iterBind= (DCIteratorBinding)dcBindings.get("testIterator");
String attribute = (String)iterBind.getCurrentRow().getAttribute("field1");



// Get the error 
String error = iterBind.getError().getMessage();



// refresh the iterator 
bindings.refreshControl();
iterBind.executeQuery();
iterBind.refresh(DCIteratorBinding.RANGESIZE_UNLIMITED);



// Get all the rows of a iterator 
Row[] rows = iterBind.getAllRowsInRange();
TestData dataRow = null;
for (Row row : rows) {
dataRow = (TestData)((DCDataRow)row).getDataProvider();
}



// Get the current row of a iterator , a different way 
FacesContext ctx = FacesContext.getCurrentInstance();
ExpressionFactory ef = ctx.getApplication().getExpressionFactory();
ValueExpression ve = ef.createValueExpression(ctx.getELContext(), "#{bindings.testIter.currentRow.dataProvider}", TestHead.class);
TestHead test = (TestHead)ve.getValue(ctx.getELContext());



// Get a session bean 
FacesContext ctx = FacesContext.getCurrentInstance();
ExpressionFactory ef = ctx.getApplication().getExpressionFactory();
ValueExpression ve = ef.createValueExpression(ctx.getELContext(), "#{testSessionBean}", TestSession.class);
TestSession test = (TestSession)ve.getValue(ctx.getELContext());



// main jsf page 
DCBindingContainer dc = (DCBindingContainer)BindingContext.getCurrent().getCurrentBindingsEntry();


// taskflow binding 
DCTaskFlowBinding tf = (DCTaskFlowBinding)dc.findExecutableBinding("dynamicRegion1");


// pagedef of a page fragment 
JUFormBinding form = (JUFormBinding) tf.findExecutableBinding("regions_employee_regionPageDef");



// handle to binding container of the region. 
DCBindingContainer dcRegion = form;




// return a methodexpression like a control flow case action or ADF pagedef action 
private MethodExpression getMethodExpression(String name) {
Class [] argtypes = new Class[1];
argtypes[0] = ActionEvent.class;
FacesContext facesCtx = FacesContext.getCurrentInstance();
Application app = facesCtx.getApplication();
ExpressionFactory elFactory = app.getExpressionFactory();
ELContext elContext = facesCtx.getELContext();
return elFactory.createMethodExpression(elContext,name,null,argtypes);
}



// get a value 
private ValueExpression getValueExpression(String name) {
FacesContext facesCtx = FacesContext.getCurrentInstance();
Application app = facesCtx.getApplication();
ExpressionFactory elFactory = app.getExpressionFactory();
ELContext elContext = facesCtx.getELContext();
return elFactory.createValueExpression(elContext, name, Object.class);
}




// an example how to use this 
RichInputText input = new RichInputText();
input.setValueExpression("value",getValueExpression("#{bindings."+item+".inputValue}"));
input.setValueExpression("label",getValueExpression("#{bindings."+item+".hints.label}"));
input.setId(item);
panelForm.getChildren().add(input);





// catch an exception and show it in the jsf page
catch(Exception e) {
FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_ERROR, e.getMessage(), "");
FacesContext.getCurrentInstance().addMessage(null, msg);
}

FacesMessage msg = new FacesMessage(FacesMessage.SEVERITY_WARN, msgHead , msgDetail);
facesContext.addMessage(uiComponent.getClientId(facesContext), msg);




// reset all the child uicomponents 
private void resetValueInputItems(AdfFacesContext adfFacesContext,
UIComponent component){
List items = component.getChildren();
for ( UIComponent item : items ) {

resetValueInputItems(adfFacesContext,item);

if ( item instanceof RichInputText ) {
RichInputText input = (RichInputText)item;
if ( !input.isDisabled() ) {
input.resetValue() ;
adfFacesContext.addPartialTarget(input);
};
} else if ( item instanceof RichInputDate ) {
RichInputDate input = (RichInputDate)item;
if ( !input.isDisabled() ) {
input.resetValue() ;
adfFacesContext.addPartialTarget(input);
};
}
}
}




// redirect to a other url 
ExternalContext ectx = FacesContext.getCurrentInstance().getExternalContext();
HttpServletResponse response = (HttpServletResponse)ectx.getResponse();
String url = ectx.getRequestContextPath()+"/adfAuthentication?logout=true&end_url=/faces/start.jspx";

try {
response.sendRedirect(url);
} catch (Exception ex) {
ex.printStackTrace();
}




// PPR refresh a jsf component 
AdfFacesContext.getCurrentInstance().addPartialTarget(UIComponent);




// find a jsf component 
private UIComponent getUIComponent(String name) {
FacesContext facesCtx = FacesContext.getCurrentInstance();
return facesCtx.getViewRoot().findComponent(name) ;
}




// get the adf bc application module 
private OEServiceImpl getAm(){
FacesContext fc = FacesContext.getCurrentInstance();
Application app = fc.getApplication();
ExpressionFactory elFactory = app.getExpressionFactory();
ELContext elContext = fc.getELContext();
ValueExpression valueExp =
elFactory.createValueExpression(elContext, "#{data.OEServiceDataControl.dataProvider}",
Object.class);
return (OEServiceImpl)valueExp.getValue(elContext);
}




// change the locale 
Locale newLocale = new Locale(this.language);
FacesContext context = FacesContext.getCurrentInstance();
context.getViewRoot().setLocale(newLocale);




// get the stacktrace of a not handled exception 
private ControllerContext cc = ControllerContext.getInstance();

public String getStacktrace() {
if ( cc.getCurrentViewPort().getExceptionData()!=null ) {
StringWriter sw = new StringWriter();
PrintWriter pw = new PrintWriter(sw);
cc.getCurrentViewPort().getExceptionData().printStackTrace(pw);
return sw.toString();
}
return null;
}




// get the selected rows from a table component 
RowKeySet selection = resultTable.getSelectedRowKeys();
Object[] keys = selection.toArray();
List receivers = new ArrayList
(keys.length);
for ( Object key : keys ) {
User user = modelFriends.get((Integer)key);
}




// get selected Rows of a table 2 
for (Object facesRowKey : table.getSelectedRowKeys()) {
table.setRowKey(facesRowKey);
Object o = table.getRowData();
JUCtrlHierNodeBinding rowData = (JUCtrlHierNodeBinding)o;
Row row = rowData.getRow();
Test testRow = (Test)((DCDataRow)row).getDataProvider() ;
}


Read more-http://tamanmohamed.blogspot.com/2011/08/adf-jsf-some-handy-code-for-backing.html