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I'm writing my custom table composite component with Mojarra JSF. I'm also trying to bind that composite to a backing component. The aim is to be able to specify the number of elements the table has in a composite attribute, later on the bound backing component will autogenerate the elements itself before view gets rendered. I've this sample code:
Main page:
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:f="http://java.sun.com/jsf/core"
xmlns:h="http://java.sun.com/jsf/html"
xmlns:comp="http://java.sun.com/jsf/composite/comp">
<h:head />
<body>
<h:form>
<comp:myTable itemNumber="2" />
</h:form>
</body>
</html>
myTable.xhtml:
<html xmlns="http://www.w3.org/1999/xhtml"
xmlns:composite="http://java.sun.com/jsf/composite"
xmlns:h="http://java.sun.com/jsf/html">
<h:body>
<composite:interface componentType="components.myTable">
<composite:attribute name="itemNumber"
type="java.lang.Integer" required="true" />
</composite:interface>
<composite:implementation>
<h:dataTable value="#{cc.values}" var="value">
<h:column headerText="column">
#{value}
<h:commandButton value="Action" action="#{cc.action}" />
</h:column>
</h:dataTable>
</composite:implementation>
</h:body>
</html>
MyTable.java:
@FacesComponent("components.myTable")
public class MyTable extends UINamingContainer {
private List<String> values = new ArrayList<String>();
public void action() {
System.out.println("Called");
}
@Override
public void encodeBegin(FacesContext context) throws IOException {
// Initialize the list according to the element number
Integer num = (Integer) getAttributes().get("itemNumber");
for (int i = 0; i < num; i++) {
values.add("item" + i);
}
super.encodeBegin(context);
}
public List<String> getValues() {
return values;
}
}
The issue is table gets rendered properly (in this case with two items), but action method doesn't get called when pressing the button on the lines.
If I follow the wiki page for composite components, I can get it work in that way, but having to initialize the List each time getValues() is called, introducing logic into the getter method :-(.
Any idea about that? It seems to be a trouble related with overriding encodeBegin method. I also tried initializing it on markInitialState, but attributes are not yet available there...
Tested with Mojarra 2.1.27 + Tomcat 6-7 & Mojarra 2.2.5 + Tomcat 7
201
As to the cause, UIComponent instances are inherently request scoped. The postback effectively creates a brand new instance with properties like values reinitialized to default. In your implementation, it is only filled during encodeXxx(), which is invoked long after decode() wherein the action event needs to be queued and thus too late.
You'd better fill it during the initialization of the component. If you want a @PostConstruct-like hook for UIComponent instances, then the postAddToView event is a good candidate. This is invoked directly after the component instance is added to the component tree.
<cc:implementation>
<f:event type="postAddToView" listener="#{cc.init}" />
...
</cc:implementation>
with
private List<String> values;
public void init() {
values = new ArrayList<String>();
Integer num = (Integer) getAttributes().get("value");
for (int i = 0; i < num; i++) {
values.add("item" + i);
}
}
(and remove the encodeBegin() method if it isn't doing anything useful anymore)
An alternative would be lazy initialization in getValues() method.
62
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