UISelectMany - Conversion error with HashMap Property

Question

Hi,
I have a Backing Bean with a HashMap Property.
public HashMap getItem()
public void setItem(HashMap map)
so I bind a Value of an UIInputText Component like that:
<h:inputText id="txtname" value="#{MyBean.item['myKey']}" />
this works pretty well.
But when I try to do the same with an <h:selectManyCheckbox> Component I got a "Conversion Error".
For what reason? I expected an Array or List Object.
Thanks for help
Ralph

Answer 1

I solved the problem by creating a custom converter, which checks if the current valueBinding is null.
If so, it replace the valueBinding with an empty ArrayList().
public class MultiValueConverter implements Converter {
     public final static String CONVERTER_ID = "org.imixs.workflow.j2ee.faces.MultiValueConverter";
     public Object getAsObject(FacesContext context, UIComponent component, String value) throws ConverterException {
// no changes
return value;
     public String getAsString(FacesContext context, UIComponent component, Object value) throws ConverterException {
// Check if current value Binding is bind to an null-Object
javax.faces.el.ValueBinding valueBinding=component.getValueBinding("value");
if (valueBinding!=null && valueBinding.getValue(context)==null) {
// replace binding with empty ArrayList
valueBinding.setValue(context,new ArrayList());
// no changes
return value.toString();
you can find the full code under www.imixs.org (an open source project for a EJB based workflow engine)