Question

I have the following method in my bean

    public void valueChange(ValueChangeEvent event){

        oldValue = (String) event.getOldValue();
        newvalue = (String) event.getNewValue();

 logger.info("values " + oldValue + " to " + newvalue );

And in my JSF

 <h:selectOneListbox size="1" 
 value="#{bean.Emp}"   onchange="this.form.submit()"
 valueChangeListener="#{bean.valueChange}

I could see that oldValue is always null, what could be the reason for this?

My JSF version is 1.1 and page scope is request.

Thanks

Update 1

Backing Bean

public class EmpBackingBean {

    private String selectedItemEmp;

    public void selectedItemEmp(String selectedItemEmp) {
        this.selectedItemEmp= selectedItemEmp;
    }

    public String getSelectedItemEmp() {
        return selectedItemEmp;
    }

Managed Bean

    EmpBackingBean empBackingBean = new EmpBackingBean();


    public EmpBackingBean getVehDetBackingBean() {
        return empBackingBean ;
    }

public void valueChange(ValueChangeEvent event){

        oldValue = (String) event.getOldValue();
        newvalue = (String) event.getNewValue();

logger.info("values " + oldValue + " to " + newvalue );

}

Answer 1

The HTML form does not submit the last rendered form values if that is what you are expecting.

public class Bean {
  private Object emp;
  public Object getEmp() { return emp; }
  public void setEmp(Object emp) { this.emp = emp; }
}

The old value is the value in “bean” when the form is submitted. If “bean” is request scope, a new instance will be created every time. I am guessing “Emp” is not initialized, so it will be null.