In order to get the row numbers of a datatable I got an answer here that I could bind the dataTable directly to the view (JSF 2 dataTable row index without dataModel).
I'm using that function in a composite component and there may be several of those in the same page. I believe that the binding makes it impossible to use more than one component on each page; is it possible to bind each table "separately" somehow?
Create a backing component class with an UIData property.
#FacesComponent("fooComponent")
public class FooComponent extends UINamingContainer {
private UIData table;
// +getter +setter
}
And bind it to #{cc.table} instead (the #{cc} refers the current backing component instance).
<cc:interface componentType="fooComponent">
...
</cc:interface>
<cc:implementation>
<h:dataTable binding="#{cc.table}" ...>
<h:column>#{cc.table.rowIndex + 1}</h:column>
...
</h:dataTable>
</cc:implementation>
Just use ui:repeat instead, it has built in support via varStatus.index.
Related
Following on from the response by the legendary BalusC to this post:
How to programmatically or dynamically create a composite component in JSF 2
Had I sufficient points I would attach a comment to that post -- but I don't have sufficient points .
Problem as follows.
I'm trying to set up a commandButton which adds a JSF composite component dynamically to an xhtml file. With the intention that clicking it multiple times will put multiple instances of the component on the page.
So I have a button on an XHTML file:
<h:commandButton action="#{assessingController.addQuestion}" value="Add a Question"></h:commandButton>
Which calls a method on AssessingController:
public void addQuestion() {
UIComponent parent = null;
includeCompositeComponent(parent, "http://xmlns.jcp.org/jsf/composite/components", "questionComposite", "someId");
}
UIComponent parent = null; -- because it has to be instantiated or referenced somehow, before being passed into includeCompositeComponent . But as noted below - making it null might be causing the null pointer exception, (so what should I do instead?)
includeCompositeComponent method is as per the JSF 2.2 method referred to by BalusC in the above post:
public void includeCompositeComponent(UIComponent parent, String taglibURI, String tagName, String id) {
FacesContext context = FacesContext.getCurrentInstance();
UIComponent composite = context.getApplication().getViewHandler()
.getViewDeclarationLanguage(context, context.getViewRoot().getViewId())
.createComponent(context, taglibURI, tagName, null);
composite.setId(id);
parent.getChildren().add(composite);
}
When I click on the commandButton, logs as follows:
javax.faces.el.EvaluationException: java.lang.NullPointerException
at javax.faces.component.MethodBindingMethodExpressionAdapter.invoke(MethodBindingMethodExpressionAdapter.java:101)
at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:102)
at javax.faces.component.UICommand.broadcast(UICommand.java:315) ...
Caused by: java.lang.NullPointerException
at controllers.AssessingController.includeCompositeComponent(AssessingController.java:123)
AssessingController.java:123 is this line:
parent.getChildren().add(composite);
Composite is not null (checked that).
So, obviously perhaps, - parent is null and that's where the problem is.
So how can I better reference UIComponent parent to begin with?
Do I need to make it refer to something on the xhtml file? I'm presuming it needs some kind of a placeholder which will serve as the parent(?). Right now all there is on the xhtml page is the commandButton.
Thank you all.
The parent is supposed to represent the component where you'd like to include the composite component in.
Imagine that you ultimately want to end up with this plain XHTML representation:
<h:panelGroup id="questions">
<your:questionComposite />
</h:panelGroup>
You should then supply exactly that <h:panelGroup> component as parent.
<h:form>
<h:commandButton ... action="#{bean.addQuestion}" />
</h:form>
<h:panelGroup id="questions" />
public void addQuestion() {
UIComponent parent = context.getViewRoot().findComponent("questions");
// ...
}
Or, by passing the concrete component itself:
<h:form>
<h:commandButton ... action="#{bean.addQuestion(questions)}" />
</h:form>
<h:panelGroup id="questions" binding="#{questions}" />
public void addQuestion(UIComponent parent) {
// ...
}
Unrelated to the concrete problem: there's a thinking/design mistake here. You should rather use an <ui:repeat><your:compositeComponent> and then feed from a #ViewScoped bean to the <ui:repeat> a dynamically sized list of entities representing the composite's model value.
<h:form>
<h:commandButton ... action="#{bean.addQuestion}" />
</h:form>
<ui:repeat value="#{bean.questions}" var="question">
<your:questionComposite value="#{question}" />
</ui:repeat>
private List<Question> questions;
public void addQuestion() {
questions.add(new Question());
}
Anytime you need to deal with raw UIComponent instances in a backing bean, take a pause and carefully research or ask if you're really doing things the right way. Perhaps it belongs in a backing component instead, or could just be done with pure XHTML.
See also:
How to dynamically add JSF components
How does the 'binding' attribute work in JSF? When and how should it be used?
I want to display java arraylist into JSF page. I generated arraylist from database. Now I want to display the list into JSF page by calling the list elements index by index number. Is it possible to pass a parameter to bean method from an EL expression in JSF page directly and display it?
You can access a list element by a specific index using the brace notation [].
#ManagedBean
#RequestScoped
public class Bean {
private List<String> list;
#PostConstruct
public void init() {
list = Arrays.asList("one", "two", "three");
}
public List<String> getList() {
return list;
}
}
#{bean.list[0]}
<br />
#{bean.list[1]}
<br />
#{bean.list[2]}
As to parameter passing, surely it's possible. EL 2.2 (or JBoss EL when you're still on EL 2.1) supports calling bean methods with arguments.
#{bean.doSomething(foo, bar)}
See also:
Our EL wiki page
Invoke direct methods or methods with arguments / variables / parameters in EL
I however wonder if it isn't easier to just use a component which iterates over all elements of the list, such as <ui:repeat> or <h:dataTable>, so that you don't need to know the size beforehand nor to get every individual item by index. E.g.
<ui:repeat value="#{bean.list}" var="item">
#{item}<br/>
</ui:repeat>
or
<h:dataTable value="#{bean.list}" var="item">
<h:column>#{item}</h:column>
</h:dataTable>
See also:
How iterate over List<T> and render each item in JSF Facelets
Hi Have this Wierd Issue in which I am using a Composite Component which I wrote and I get values from the previous use of the backing bean of the CC (the componentType bean)
I don't know how to describe this better than just show the code.
I'll try to be brief about it and cut the redundant parts:
This is the Composite Component definition:
<cc:interface componentType="dynamicFieldGroupList">
<cc:attribute name="coupletClass" />
<cc:attribute name="form" default="#form"/>
<cc:attribute name="list" type="java.util.List" required="true"/>
<cc:attribute name="fieldNames" type="java.util.List" required="true" />
</cc:interface>
<cc:implementation>
<h:dataTable value="#{cc.model}" var="currLine">
<h:column>
<h:outputText id="inner_control_component" value="Inner Look at currLine:#{currLine}"/>
</h:column>
</h:dataTable>
</cc:implementation>
The CC bean defintion:
#FacesComponent(value = "dynamicFieldGroupList")
// To be specified in componentType attribute.
#SuppressWarnings({ "rawtypes", "unchecked" })
// We don't care about the actual model item type anyway.
public class DynamicFieldGroupList extends UIComponentBase implements
NamingContainer
{
private transient DataModel model;
#Override
public String getFamily()
{
return "javax.faces.NamingContainer"; // Important! Required for
// composite components.
}
public DataModel getModel()
{
if (model == null)
{
model = new ListDataModel(getList());
}
return model;
}
private List<Map<String, String>> getList()
{ // Don't make this method public! Ends otherwise in an infinite loop
// calling itself everytime.
return (List) getAttributes().get("list");
}
}
And the use code:
<ui:repeat var="group" value="#{currentContact.detailGroups}">
<h:panelGroup rendered="#{not empty group.values}">
<h:outputText id="controlMsg" value=" list:#{group.values}" /><br/><br/>
<utils:fieldTypeGroupList list="#{group.values}"
fieldNames="#{group.fields}" coupletClass="utils" />
</h:panelGroup>
</ui:repeat>
The text of id controlMsg displays the correct values in #{group.values} while the control output inside the component of id inner_control_component shows the values from the previous use.
The values are correct the first time...
I guess it's a fundemental error in use of a CC bean, otherwise it could be a bug with MyFaces 2.1 (Which I'm using)
The explanation for this behaviour is simple: there's only one component definied in the view. So there's also only one backing component with one model. Since the model is lazily loaded on first get, the same model is been reused in every iteration of a parent iterating component.
The <ui:repeat> doesn't run during view build time (as JSTL does), but during view render time. So there are physically not as many components in the view as items which are iterated by <ui:repeat>. If you were using <c:forEach> (or any other iteration tag which runs during view build time), then the composite component would have behaved as you'd expect.
You would like to change the way how the datamodel is kept in the backing component. You would like to preserve a separate datamodel for each iteration of a parent iterating component. One of the ways is to replace the model property as follows:
private Map<String, DataModel> models = new HashMap<String, DataModel>();
public DataModel getModel() {
DataModel model = models.get(getClientId());
if (model == null) {
model = models.put(getClientId(), new ListDataModel(getList()));
}
return model;
}
See also:
What's the view build time?
The problem described here is an old known isse in JSF, hidden by the usage of composite components. It is so important and so difficult, that instead answer here I create a detailed answer in a blog entry for this one: JSF component state per row for datatables
To keep this answer short, I'll say to you it is not a bug in MyFaces 2.1. Please use 2.1.1, because that is a quick bug fix version of 2.1.0. In JSF 2.1 there is a new property for h:dataTable called rowStatePreserved, and this scenario is just one case where "this little baby" becomes useful. Just replace ui:repeat with h:dataTable and add rowStatePreserved="true". That will do the trick. If you need to manipulate the model (add or remove rows) you can use tomahawk t:dataTable and t:dataList, but you will have to take an snapshot version for now. Note this is new stuff not available in any different JSF framework an the moment (JUN 2011).
If you need more info, keep tuned with MyFaces Team on Twitter or ask to the experts on MyFaces Users and Dev Mailing Lists.
I have a managed bean under ViewScope. It has an instance variable inside it.
MetaData object has a inputItem object List.
#ManagedBean
#ViewScoped
public class ConBean implements Serializable {
private MetaData metadata;
#PostConstruct
#SuppressWarnings("unchecked")
public void init() throws IOException {
this.metadata = new MetaData ();
}
public void proc(){
List<InputItem> inputs= new ArrayList<InputItem>();
inputs.add(***** code to populate the inputItem List);
//after populating, inputs added to the metadata
metadata.setInputs(inputs);
}
//getters & setters
}
in my JSF , input list is populated inside a UI repeat.
<div id="inputplaceholder">
<ui:repeat value="#{conBean.metaData.inputs}" var="content">
</ui:repeat>
</div>
the div inputplaceholder is periodically updated using a richfaces poll.
<a4j:poll id="poll" interval="12000" action="#{conBean.proc}"
execute="#form" render="inputplaceholder"/>
The problem that I have is even though inputItems are set to the metaData object correctly inside the proc() method, when the view is rendered/partially updated, it doesn't get highlighted in the UI. so partial update takes no effect. I tried moving
this.metadata = new MetaData ();
inside the proc method but had no luck.
any ideas and help is highly appreciated.
thanks ...
Did the partial render really take place? This is impossible. There is namely no JSF component with the ID inputplaceholder. You assigned it to a plain HTML <div> element. Replace it by a fullworthy JSF component:
<h:panelGroup layout="block" id="inputplaceholder">
Also, since you used a relative ID in the render attribute, it will only scan for components in the same parent naming container component. The <ui:repeat> is such one, however the component with the desired ID is placed outside it. You'd like to use an absolute ID instead. Assuming that it's inside a <h:form> with a fixed ID:
<h:form id="myform">
<h:panelGroup layout="block" id="inputplaceholder">
...
then you should be referencing it in the render attribute as follows
render=":myform:inputplaceholder"
I have a problem to bind list of h:selectBooleanCheckbox to my bean.
Anybody helps ?
This is not working:
<ui:repeat value="#{cartBean.productsList}" var="cartProduct" varStatus="i">
<h:selectBooleanCheckbox binding="#{cartBean.checkboxes[i.index]}" />
</ui:repeat>
public class CartBean extends BaseBean {
public List<Product> getProductsList() {...}
private HtmlSelectBooleanCheckbox[] checkboxes;
public HtmlSelectBooleanCheckbox[] getCheckboxes() {
return checkboxes;
}
public void setCheckboxes(HtmlSelectBooleanCheckbox[] checkboxes) {
this.checkboxes = checkboxes;
}
}
I get error:
javax.faces.FacesException: javax.el.PropertyNotFoundException: /WEB-INF/flows/main/cart.xhtml #26,97 binding="#{cartBean.checkboxes[i.index]}": Target Unreachable, 'checkboxes' returned null
I solved my problem. I used code like below and get what i want (thanks to BalusC blog - http://balusc.blogspot.com/2006/06/using-datatables.html#SelectMultipleRows):
<ui:repeat value="#{cartBean.productsList}" var="cartProduct" varStatus="i">
<h:selectBooleanCheckbox value="#{cartBean.selectedIds[cartProduct.id]}" />
</ui:repeat>
public class CartBean extends BaseBean {
private Map<Integer, Boolean> selectedIds = new HashMap<Integer, Boolean>();
public Map<Integer, Boolean> getSelectedIds() {
return selectedIds;
}
}
Your concrete problem is caused because the binding attribute is evaluated during view build time, that moment when the XHTML source code is turned into a JSF UI component tree, while the <ui:repeat> runs during view render time, that moment when the JSF UI component tree needs to produce HTML.
In other words, the #{i.index} is only available during view render time and evaluates as null during view build time. In effects, you're doing a binding="#{cartBean.checkboxes[null]}"
There's another conceptual mistake here: you seem to expect that the <ui:repeat> produces physically multiple <h:selectBooleanCheckbox> components. This is untrue. There's physically only one <h:selectBooleanCheckbox> which is reused multiple times to produce HTML based on the currently iterated variable. Actually, binding="#{cartBean.checkbox}" was been sufficient. However, collecting the values is a story apart. I won't go in detail, but you can find several hints in this answer: Validate order of items inside ui:repeat.
In order to achieve the (apparent) concrete functional requirement of generating physically multiple <h:selectBooleanCheckbox> components and binding each to a separate array item, you should be using an iteration component which runs during view build time instead of view render time. That's the JSTL <c:forEach>:
<c:forEach items="#{cartBean.productsList}" var="cartProduct" varStatus="i">
<h:selectBooleanCheckbox binding="#{cartBean.checkboxes[i.index]}" />
</c:forEach>
But, after all, using binding on a bean property should be avoided as much as possible. Use instead exactly that attribute which you ultimately need: the value attribute. This way you don't need to do a HtmlSelectBooleanCheckbox#getValue() everytime. You already figured the right solution with a Map<Integer, Boolean> selectedIds:
<ui:repeat value="#{cartBean.productsList}" var="cartProduct">
<h:selectBooleanCheckbox value="#{cartBean.selectedIds[cartProduct.id]}" />
</ui:repeat>
See also:
JSTL in JSF2 Facelets... makes sense?
I don't know if you can bind elements stored in an array. But in your code, the problem is that your HtmlSelectBooleanCheckbox[] is null. So maybe change your Java code to:
public HtmlSelectBooleanCheckbox[] getCheckboxes() {
if (checkboxes == null) {
checkboxes = new HtmlSelectBooleanCheckbox[getProductsList().size()];
}
return checkboxes;
}
but I am really not sure if it will work... Maybe the solution is to not bind your HtmlSelectBooleanCheckbox elements in the Java code. Why do you need to bind them?