I have a problem which occurs using Labda Expression and JSF 2.2
No matter which tag I use, as soon as the calling method contains a lamda expression, the method ist not called.
<p:commandButton action="#{bean.doSomthing}" />
public void doSomthing() {
// never called
// Lambda stuff happening
List<Customer> charlesWithMoreThan100Points = customers
.stream()
.filter(c -> c.getPoints() > 100 && c.getName().startsWith("Charles"))
.collect(Collectors.toList());
}
Without the Lambda Expression the Method is called as expected.
Debugging the actionListener has shown the this.value.getValue(elContext) does not trigger a call to the action method in the backing bean.
public void processAction(ActionEvent actionEvent) throws AbortProcessingException {
FacesContext context = FacesContext.getCurrentInstance();
ELContext elContext = context.getELContext();
StreamedContent content = (StreamedContent)this.value.getValue(elContext);
// content is null. Value returning method is not called.
Related
Mojarra 2.2
I have two beans`.
public class MyBean1{
private String myProperty1;
//GET, SET, CTOR
public void doAction(){
//assign something to myProperty1
}
}
public class MyBean2{
private String myProperty2;
//GET, SET, CTOR
}
Now, I need to assign the value of the property MyBean1::myProperty1 to MyBean2::myProperty2 after the doAction() method invocation by clicking a button:
<h:commandButton action="#{myBean1.doAction}">
<f:setPropertyActionListener target="#{myBean2.myProperty2}"
value="#{myBean1.myProperty1}" />
</h:commandButton>
But it doesn't work. And I figured out that it doesn't work due to the following reason:
Clicking a button causes ActionEvent to be broadcasted. It performs by this method (javax.faces.component.UICommand):
public void broadcast(FacesEvent event) throws AbortProcessingException {
super.broadcast(event); //1 <-------------------- HERE
if (event instanceof ActionEvent) {
FacesContext context = getFacesContext();
MethodBinding mb = getActionListener();
if (mb != null) {
mb.invoke(context, new Object[] { event });
}
ActionListener listener =
context.getApplication().getActionListener();
if (listener != null) {
listener.processAction((ActionEvent) event);
}
}
}
I've noticed that the ActionEvent broadcasting by clickng the button is being handled by two listeners and one that comes from super.broadcast(event) invokation at //1 is com.sun.faces.facelets.tag.jsf.core.SetPropertyActionListenerHandler.SetPropertyListener.
The handling is performed before invokation of the action method.
Of course, I can embed the action method invokation into the MyBean1:getMyProperty1() getter, so the myProperty1 field will be properly intialized, but it seems quite wierd to me. What is the right way to achieve that?
I'm making page using Primefaces with form with ability to ajax-upload image and preview it before submitting whole form.
To achieve this I made dialog outside main form:
<p:dialog id="imageDlg" header="Load Image" modal="true"
widgetVar="imageUploadWidget">
<h:form id="imageForm" enctype="multipart/form-data">
<p:fileUpload mode="advanced" auto="true" sizeLimit="9999999"
allowTypes="/(\.|\/)(gif|jpe?g|png)$/"
fileUploadListener="#{pageBean.imageUploadHandler}">
</p:fileUpload>
</h:form>
</p:dialog>
Inside main form there is p:graphicImage component to display just uploaded image and button to show dialog. Page is backed by view scoped bean (PageBean), but to pass StreamedContent to p:graphicImage value bean should be session or application scoped (because method called multiply times). So I made second application scoped bean (ImageBean) only for this purpose.
<p:graphicImage value="#{imageBean.imageStreamedContent()}"/>
<p:commandButton value="Choose image" type="button"
onclick="imageUploadWidget.show();"/>
Code of ImageBean:
#ApplicationScoped
#ManagedBean
public class ImagesBean implements Serializable {
private byte[] image;
//getter & setter
public StreamedContent imageStreamedContent() {
FacesContext context = FacesContext.getCurrentInstance();
if (context.getCurrentPhaseId() == PhaseId.RENDER_RESPONSE) {
return new DefaultStreamedContent();
} else {
return new DefaultStreamedContent(new ByteArrayInputStream(getImage()));
}
}
}
The next part is fileUploadListener. Idea is simple — set corresponding fields of PageBean (to save it later on form submit) of ImageBean (to show it after partial refresh) and update part of main form:
#ManagedBean
#ViewScoped
public class PageBean implements Serializable {
#ManagedProperty(value="#{imageBean}")
ImagesBean imagesBean;
...
public void imageUploadHandler(FileUploadEvent event) {
getImagesBean().setImage(event.getFile().getContents());
RequestContext.getCurrentInstance().update("form:tabPanel1");
}
Here comes strange thing. Inside setImage() method everything is OK - field is set, getter works fine. But then page refresh, imageBean.getImage() inside imageBean.imageStreamedContent() returns null.
More accurate — it returns old value, as if setter was never called or was called on another instance of bean. I checked it on another String field: initialized it in ImageBean constructor, in handler invoked setter with another value and refreshed part of main form. Same thing: old value from constructor.
I think, that I'm missing something about bean life cycle or scope specific. Or maybe there is less complicated way to implement this task?
There is a problem with using StreamedContent in Primefaces for p:graphicImage and p:media.
You can see Cagatay Civici 's comments on this topic in Primefaces forum here.
In my experience, when I had the slimier(more or less) problem This and This answers by BalusC helped me.
I used a saperate Servlet instead of Managedbean to stream the dynamic content to p:media (in mycase).
Here is my code for your reference(if you need any):
PreviewFileServlet.java
#WebServlet("/PreviewFile")
public class PreviewFileServlet extends HttpServlet {
public PreviewFileServlet() {
super();
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
ServletContext context = request.getServletContext();
String path = request.getParameter("PREVIEW_FILE_PATH");
logger.info("Received pathe for Preview:"+path);
try{
if(null!=path){
java.io.File f = new java.io.File(path);
if(f.exists()){
FileInputStream fin = new FileInputStream(f);
byte b[] = new byte[(int)f.length()];
fin.read(b);
response.setContentLength(b.length);
response.setContentType(context.getMimeType(path));
response.getOutputStream().write(b);
response.getOutputStream().close();
logger.info("File sent successfully for Preview.");
}
else{
logger.warn("File sepecified by path:-"+path+"-:, NOT found");
}
}
}catch(Exception e){
}
}
/**
* #see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
Facelet Code
<p:media value="/PreviewFile?PREVIEW_FILE_PATH=#{fileManager.previewFilePath}" />
Hope this helps.
And there are lot of questions on this topic of StreamedContent in stackoverflow itself, go through them once.
Following java code allows to access any object or variable from faces context:
ELContext elCtx = facesContext.getELContext();
ExpressionFactory exprFac = facesContext.getApplication().getExpressionFactory();
MyProperty myProperty = (MyProperty) exprFac.createValueExpression(elCtx, "#{somebean.someattr.someproperty}", MyProperty.class).getValue(elCtx);
I use the code from within my custom converter to read additional converting parameters from context.
The code works correctly if #{somebean} is defined as normal backing bean within JSF context.
Facelets allow to create 'shortcut' to JSF expressions. Example:
<ui:param name="shortcut" value="#{somebean.someattr.someproperty}" />
<div>#{somebean.someattr.someproperty} equals #{shortcut}</div>
In this case both #{somebean.someattr.someproperty} and #{shortcut} have the same value.
However these 'shortcut' names are not accessible using java code above. For example:
MyProperty myProperty1 = (MyProperty) exprFac.createValueExpression(elCtx, "#{somebean.someattr.someproperty}", MyProperty.class).getValue(elCtx);
// myProperty1 has expected value
MyProperty myProperty2 = (MyProperty) exprFac.createValueExpression(elCtx, "#{shortcut}", MyProperty.class).getValue(elCtx);
// myProperty2 is null
Is there a way to access a facelets context and to read 'shortcut' parameter values, defined on the current JSF page?
I had the same problem and have chosen the following approach:
/**
* Führt eine Expression im aktuellen Faces EL Context
* UND im Facelets El Context aus.
*
* #param facesContext
* #param expression
* #return object
*/
private static Object executeExpressionInUIContext (final FacesContext facesContext, final String expression) {
final ELContext elContext = facesContext.getELContext();
final Application application = facesContext.getApplication();
Object result = executeExpressionInElContext(application, elContext, expression);
if (null == result) {
FaceletContext faceletElContext = (FaceletContext) FacesContext.getCurrentInstance().getAttributes().get(FaceletContext.FACELET_CONTEXT_KEY);
result = executeExpressionInElContext(application, faceletElContext, expression);
}
return result;
}
private static Object executeExpressionInElContext (Application application, ELContext elContext, String expression) {
ExpressionFactory expressionFactory = application.getExpressionFactory();
ValueExpression exp = expressionFactory.createValueExpression(elContext, expression, Object.class);
return exp.getValue(elContext);
}
"ui:param" is part of the Facelet view handling technology. Facelets extends JSF.
Both technologies use their own Context when storing variables.
Beside the Faces El Context there is a Facelet El Context (FaceletContext).
The stated method evaluates expressions in both contexts. Be aware that this will not work if two values are stored under the same name in each context.
It seems that facelet shortcuts do not exist in the context, where I try to access them.
I have made following workaround: On JSF page where my input element is placed, I have added a <f:param> element as child of the input with my converter.
<h:inputText id="myid" value="#{action.myinput}">
<f:converter converterId="myConverter" />
<f:param name="converterParameters" shortcut="#{somebean.someattr.someproperty}"/>
</h:inputText>
Then in converter I'm able to find UIParam element as one of the input children and read my shortcuts from it.
public Object getAsObject(FacesContext context, UIComponent component, String value) {
MyProperty myProperty = null;
try {
for (final UIComponent child : component.getChildren()) {
if ("converterParameters".equals(child.getAttributes().get("name"))) {
final ELContext elCtx = context.getELContext();
myProperty = (MyProperty) child.getValueExpression("shortcut").getValue(elCtx);
break;
}
}
if (myProperty == null) {
throw new NullPointerException("My property is undefined.");
}
} catch (Exception e) {
LOG.error("Cannot convert " + value + ". Use <f:param name=\"converterParameters\" "
+ "shortcut=\"#{here.comes.shortcut}\"/> for your input element. ", e);
throw new ConverterException("Cannot initialize converter.", e);
}
//...
}
The mapping of ui:param is not stored in context, it's in the VariableMapper of each individual ValueExpression.
So if you need to create ValueExpression programmatically, relying on another ValueExpression's varMapper, you can do something like this:
VariableMapper varMapper = new DefaultVariableMapper();
varMapper.setVariable(mappingName, component.getValueExpression(mappedAttributeName));
return new ValueExpressionImpl(expression, null, null, varMapper, expectedType);
in my JSF application i need to update ui component during invoke application phase. Can it be done? Here's the code i've produced so far:
public void resetDataScroller(ActionEvent actionEvent) {
final FacesContext ctx = FacesContext.getCurrentInstance();
ctx.getViewRoot().invokeOnComponent(ctx, "paginator_and_table:scroll_1", new ContextCallback() {
public void invokeContextCallback(FacesContext facesContext, UIComponent uiComponent) {
HtmlDatascroller htmlDatascroller = (HtmlDatascroller) uiComponent;
htmlDatascroller.setPage(1);
htmlDatascroller.setValue(1);
}
});
}
This action listener looks up dataScroller component and sets page and value to 1. Unfortunatelly it doesn't seem to work at all, because rendered dataScroller has page different than 1.
Am i missing something?
I imagine that your resetDataScroller a method called by an actionListener attribute of a command button/link on your page?
I don't really understand what you are trying to do... Do you just need to write this code? :
public void resetDataScroller(ActionEvent evt) {
final FacesContext ctx = FacesContext.getCurrentInstance();
HtmlDatascroller htmlDatascroller = (HtmlDatascroller) ctx.getViewRoot().findComponent("paginator_and_table:scroll_1");
htmlDatascroller.setPage(1);
htmlDatascroller.setValue(1);
}
If you change these properties of the HtmlDatascroller during this phase, they will be used by JSF during the last phase (the Render Response phase) to generate your HTML code...
I have to create some commandLinks dynamically and attach some action listener to it, So I've put <h:panelGrid> on the JSP page and used such code to add the commandLinks and to assign action listeners to:
public ManagedBean(){
List<UIComponenet> child = panelGrid.getChilderen();
list.clear();
List<MyClass> myList = getSomeList();
for (MyClass myObj : myList){
FacesContext ctx = FacesContext.getCurrentContext();
HtmlCommandLink cmdLink = (HtmlCommandLink) ctx.getApplication.createComponent(HtmlCommandLink.COMPONENT_TYPE);
cmdLink.setValue(myObj.getName());
cmdLink.setActionLinstner(new ActionListener(){
public void processAction(ActionEvent event) throws AbortProcessingException{
System.out.println (">>>>>>>>>>>>>>>>>I am HERE ");
}
});
child.add(cmdLink);
}
}
But unfortunately, when I press this commandLinks, an exception thrown! How can I add component event listeners at runtime?
(Note, the code above my contain syntax/compilation errors as I just wrote).
First, you need to manually assign ID to any dynamically created UINamingContainer, UIInput and UICommand components. Otherwise JSF can't locate them in the component tree based on the request parameters, because it wouldn't match the autogenerated ID's.
Thus, at least do:
HtmlCommandLink link = new HtmlCommandLink();
link.setId("linkId");
// ...
Second, you're supposed to create an ActionListener as MethodExpression as follows:
FacesContext context = FacesContext.getCurrentInstance();
MethodExpression methodExpression = context.getApplication().getExpressionFactory().createMethodExpression(
context.getELContext(), "#{bean.actionListener}", null, new Class[] { ActionEvent.class });
link.addActionListener(new MethodExpressionActionListener(methodExpression));
// ...
...and of course have the following method in the backing bean class behind #{bean}:
public void actionListener(ActionEvent event) {
// ...
}
All the above dynamic stuff basically does the same as the following raw JSF tag:
<h:commandLink id="linkId" actionListener="#{bean.actionListener}" />
I had the same problem.
Transient components do not work with actionListeners.
Do not call
FacesContext.getCurrentInstance().getViewRoot().setTransient(true);
or
component.setTransient(true);
As soon as I removed it, it was OK.