I have created a custom component. I add a dynamic input text box to it (from the encode function).
The component is correctly is rendered as HTML.
But I want to bind the value of the text box to some property on the Managed Bean. So some other developer can use the component on his jsp with his managed bean.
I want to know, what should I do, so that the value entered in the text box (which my component dynamically creates) is set to the some Managed bean property.
You need to ensure that your custom component class extends UIInput and that you're in the encodeEnd() method of your renderer writing the component's client ID as name attribute of the HTML input element. Then you can in the overriden decode() method of your renderer just grab the submitted value from the request parameter map with the component's client ID as parameter name and set it as UIInput#setSubmittedValue() and let JSF do the remnant of the job of converting, validating and updating the model value.
#Override
public void decode(FacesContext context, UIComponent component) {
// Do if necessary first validation on disabled="true" or readonly="true", if any.
// Then just get the submitted value by client ID as name.
String clientId = component.getClientId(context);
String submittedValue = context.getExternalContext().getRequestParameterMap().get(clientId);
((UIInput) component).setSubmittedValue(submittedValue);
}
Unrelated to the concrete problem, are you aware of the new composite component support in JSP's successor Facelets? I have the impression that you don't necessarily need a custom component for this purpose. Or are you really restricted to using the legacy JSP as view technology in spite of that you're already on JSF 2.x? See also When to use <ui:include>, tag files, composite components and/or custom components?
Well, the problem is solved.
In the encodeEnd() method I added the element as
HtmlInputHidden hidden = new HtmlInputHidden();
hidden.setParent(this);
hidden.setId("someId");
ValueExpression ve = getValueExpression("value");
hidden.setValueExpression("value", ve);
hidden.encodeBegin(context);
hidden.encodeEnd(context);
This seems to have some problem.
Then I changed this to ...
HtmlInputHidden hidden = new HtmlInputHidden();
hidden.setId("someId");
ValueExpression ve = getValueExpression("value");
hidden.setValueExpression("value", ve);
this.getChildren().add(hidden);
hidden.encodeBegin(context);
hidden.encodeEnd(context);
The use of this.getChildren().add(); solved my problem
P.S. Obviously before adding the element, it needs to be checked if the element is already present.
Related
Seems basic enough...
I have a custom JSF component and its associated renderer. The renderer does the decode and encodeEnd.
In decode i successfully retrie the submitted value via component.setSubmittedValue(ctx.getExternalContext().getRequestParameterMap().get(c.getClientId()));
In encodeEnd, i basically create the markup and if component.getValue() is not null, i insert its contents in the markup. So far so good.
Problem is that getValue() can be only be String. I have custom class that represents a compound data type and i want to use that as the component's local value. But doesn't work - JSF converts to String.
I also tried using component.getAttributes() - from the decode method, where i put my custom object in keyed to private static final String someKey = "asd". But later at encodeEnd there is no value/key in the map.
I want the users of this component to be able to specify in their backing bean the custom data type and not worry about serialization/deserialization to text representation between client/server. Presumably i have to use a converter for that? But how can i set up a default and immutable converter for the custom component?
The problem has a simple enough of a solution. Inside the Renderer class (or right into the Component class if using that directly):
#Override
public Object getConvertedValue(FacesContext context, UIComponent component, Object submittedValue) throws ConverterException {
SomeCustomObject thing;
//... do magic to create SomeCustomObject based on submittedValue
return thing;
}
Now whenever getValue() is called on that component, SomeCustomObject will be returned and you can safely cast to it. Also in the backing beans can use SomeCustomObject as the type.
Also note when calling component.getValue() in the actual Renderer, it will return SomeCustomObject as well, so if you're restoring state, you must convert back to its String representation.
For more details see and #Kukeltje's answer above and check how the same thing is done for primefaces calendar component here: https://github.com/primefaces/primefaces/blob/master/src/main/java/org/primefaces/component/calendar/BaseCalendarRenderer.java
For another more concise and clear illustration, check #BalusC's answer as well.
How can I get the posted form data in the backing component in the
processUpdates method?
#Override
public void processUpdates(FacesContext context) {
//get here rendered html code
}
Or can I get the posted form data in the decode method?
[Edit]:
My goal is to get the posted form data - Not to get the generated html code (Sry I wasn't precisely)
It is unclear what you want to achive, yet. I mean, at high level.
UIComponent.decode and processUpdates are medium-level lifecycle APIs which should be overriden when you want to extend the framework.
If you just need to use the framework, you need a managed bean, not a backing component.
Furthermore, generally only components that extend UIInput need to hook in those phases, because they are bound to a value="#{...}" value expression (which in turn refers to a managed bean, in most cases), and need to synchronize those values with the bound expression.
I suspect you are uselessly complicating your life: hooking into medium or low-level APIs is a real pain if you don't have an excellent understanding about how the framework operates.
Anyway, the standard request parameters decode into input component is this:
String clientId = this.getClientId(context);
Map<String, String> requestMap = context.getExternalContext().getRequestParameterMap();
String newValue = requestMap.get(clientId);
if (newValue != null)
{
this.setSubmittedValue(newValue);
}
Please, post the full xhtml facelet code (not the composite one, but the facelet using that composite), so I can understand where you want to go and I can try to point you to the right tool to use.
I want to validate values dynamically by using a custom validator that I can be used with several components. The custom validator gets those values from different ManagedBeans depending on its usage.
How to determine which ManagedBean the value is retrieved from? So I can get it, validate it, and put it back into a ManagedBean.
My Custom Validator:
#FacesValidator(value = "valid")
public class DateValidator implements Validator {
#Override
public void validate(FacesContext context, UIComponent component,
Object value) throws ValidatorException {
// Bean bean = ?
}
}
I dont think that is good approach as in validation phase model is still not updated, what you are getting is just input value from view. I wonder why you need bean instance there. If your validation depends on other component in view you can refer link # SO and Validator for multiple fields.
As you refer you need to validate it and put back, thats why validation phase is all about, validate it in your validator and if it fails it will not be passed to managed bean.
Have a look at this link for JSF lifecycle JSF Lifecycle
Hope this helps !!!
I am using JSF 2. I am trying to resolve a message bundle reference dynamically the a managed bean property. The value contains the bundle name as well as the key. This is required as the value may come from one of a few different bundles. I have tried many permutations, but the value from the bean seems to be always resolved as a literal String (outputting with EL brackets) and the bundle is never called to resolve and return the value. Any ideas?
I have tried:
#{bundle['key']}
${bundle['key']}
bundle['key']
They are outputted exactly as-is, also in a <h:outputText>. It works fine if I write it directly in the page. My theory is that JSF doesnt realise it has to process the String as an expression. Is there some way to force it?
EL will only be resolved in the view, not in the model. It would otherwise be a huge EL injection attack hole which allows endusers to enter arbitrary EL expressions in input fields and have them resolved. No, you cannot force it in any way.
You need to resolve it yourself. You can do that by either evaluating it programmatically using Application#evaluateExpressionGet():
FacesContext context = FacesContext.getCurrentInstance();
String value = context.getApplication().evaluateExpressionGet(context, "#{bundle['key']}", String.class);
// ...
Or, in this particular case, by just using the ResourceBundle API directly like as JSF is doing under the covers:
ResourceBundle bundle = ResourceBundle.getBundle(basename, FacesContext.getCurrentInstance().getViewRoot().getLocale());
String value = bundle.getString("key");
// ...
Try this..
Resource Bundle referenced by msg
USD=$
xhtml code:
<c:set var="key" value="#{managedBean.currencyCode}" />
<h:outputText value="#{msg[key]}"/>
This should work..
I have a search screen where I search for a customer id and it consumes a webservice a returns list of objects. I display the results in a datatable.For a specific field , I have a method which provides the value based on a key value in each row of the list being iterated. The key value is productID. I set that in a bean named output. In the getCustomerValue method I call the method which provides the relevant value by passing the value of "productID". I use the below listed code to do the same.
<h:outputText id="customerID" binding="#{myBean.output}" value="#{customerBean.customervalue}">
<f:attribute name="myID" value="#{item2.customerService.productID}"/>
</h:outputText>
The value gets displayed properly when the page is loaded. I have hyperlink in the same page which basically calls the same webservice and renders the same page.But this time around all the values except the value listed above is being displayed. When I print the value of attribute "item2.customerService.productID" in the method "customervalue" , it is displayed as null.I am not sure why this value isn't being passed.
You're displaying this in a <h:dataTable>. The <f:attribute> is specific to the component itself, not to its generated HTML output. The <f:attribute> is evaluated during view build time, not during the view render time. At the moment JSF builds the view, the #{item2} is not present in the scope. It's only present in the scope when JSF renders the view.
You need to look for the solution by alternate means. It's unclear what JSF version you're using, but based on your question you're using JSF 1.2 (in the future questions, please explicitly mention the JSF impl/version you're using; in JSF 2.0 a lot of things can be done differently and much more elegantly).
My answer on your previous question of Passing parameters to a method in h:outputtext tag should be the best answer to your current problem. This is apparently not an option somehow. In that case, there are at least 3 alternative ways:
Move the property to the class behind #{item2}:
<h:outputText value="#{item2.customervalue}">
You've in there instant access to the customerservice property.
Get the current item inside the getter by evaluating EL programmatically:
public String getCustomervalue() {
FacesContext context = FacesContext.getCurrentInstance();
Long productID = context.getApplication().evaluateExpressionGet(context, "#{item2.customerService.productID}", Long.class);
// ...
}
(I assume that productID is a Long)
Bind the datatable's value to a DataModel:
private DataModel<Item2> items;
with
<h:dataTable value="#{customerBean.items}" var="item2">
and
public String getCustomervalue() {
Item2 item2 = items.getRowData();
// ...
}