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Why does @PostConstruct callback fire every time even though bean is @ViewScoped? JSF

Asked 2010-05-09T09:45:10.483
32

I am using datatable on page and using binding attribute to bind it to my backing bean. This is my code :-

<?xml version='1.0' encoding='UTF-8' ?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://java.sun.com/jsf/html"
      xmlns:p="http://primefaces.prime.com.tr/ui">
    <h:head>
        <title>Facelet Title</title>
    </h:head>
    <h:body>
            <h:form prependId="false">

                <h:dataTable var="item" value="#{testBean.stringCollection}" binding="#{testBean.dataTable}">
                    <h:column>
                        <h:outputText value="#{item}"/>
                    </h:column>
                    <h:column>
                        <h:commandButton value="Click" actionListener="#{testBean.action}"/>
                    </h:column>
                </h:dataTable>

            </h:form>

    </h:body>
</html>

This is my bean :-

package managedBeans;

import java.io.Serializable;
import java.util.ArrayList;
import java.util.List;
import javax.annotation.PostConstruct;
import javax.faces.bean.ManagedBean;
import javax.faces.bean.ViewScoped;
import javax.faces.component.html.HtmlDataTable;

@ManagedBean(name="testBean")
@ViewScoped
public class testBean implements Serializable {

    private List<String> stringCollection;

    public List<String> getStringCollection() {
        return stringCollection;
    }

    public void setStringCollection(List<String> stringCollection) {
        this.stringCollection = stringCollection;
    }

    private HtmlDataTable dataTable;

    public HtmlDataTable getDataTable() {
        return dataTable;
    }

    public void setDataTable(HtmlDataTable dataTable) {
        this.dataTab
jsf facelets view-scope postconstruct
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2 Answers

4

As other said, I would say that the best thing to do is to drop component binding (you don't need it here).

But I would add that you can achieve the same as you're trying to do in a more object-oriented fashion by using action parameters, like this:

<h:commandButton value="Click" action="#{testBean.action(item)}"/>

... and in your java code:

  public void action(Item item){
    System.out.println("Clicked!!" + item);
}
answered 2011-03-16T15:10:16.787
0

If you have a viewscoped bean and if you want to retain values that were entered on the form or don't want postconstruct fired, you should return null from your action method.

If you return some outcome (e.g. invalid) and then point the invalid outcome to the same page using faces-config.xml, then the viewscoped bean gets recreated and thus it causes postconstruct to fire again.

answered 2013-03-26T17:20:53.753

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