p:autocomplete with POJO - how to get null value? - primefaces

Question

I have a simple problem. I suggest a list of objects to the user to choose from using p:autocomplete. At the same time the user can create new objects 'on the fly' by typing names that are not in the suggestion. The whole setup is very similar to the vanilla POJO showcase, but I'm posting the code here:
<p:autoComplete id="player" value="#{entry.player}"
completeMethod="{abean.complete}"
var="s1" itemLabel="#{s1.name}" itemValue="#{s1}"
converter="PlayerConverter">
<p:ajax event="itemSelect" listener="#{abean.playerSelected}"/>
</p:autoComplete>
The converter:
#FacesConverter(forClass=Player.class, value = "PlayerConverter")
public class PlayerConverter implements Converter
{
#Override
public Object getAsObject(FacesContext ctx, UIComponent cmp, String value)
{
Player player = null;
if ( !(value==null || value.trim().isEmpty()))
{
// Autocomplete did find a match, the appropriate
// player is returned
try
{
Integer id = Integer.valueOf(value);
player = TeamService.getInstance().getPlayer(id);
}
catch (NumberFormatException e)
{
// Autocomplete found no match, the entered String
// is given. Create an ad-hoc player as response
player = new Player();
player.setName(value);
player.setAdHoc(true);
}
}
return player;
}
#Override
public String getAsString(FacesContext ctx, UIComponent cmp, Object value)
{
String result = null;
if (value instanceof String)
{
result = (String) value;
}
else if (value instanceof Spieler)
{
Integer id = ((Spieler)value).getId();
result = (id == null) ? null : id.toString();
}
return result;
}
}
The problem I am facing seems simple: how do I coerce this construction into allowing the user to simply erase a value? When the user deletes the content of the input field, I would expect to get a call to PlayerConverter with a null or empty value, but that doesn't happen.
How do I get my hands on empty input?

Answer 1

I found a workaround. Use a converter and add a flag to the objects you are displaying in the p:autocomplete. Set the flag to 'false' in the converter's getAsString method. Set it to 'true' in the converter's getAsObject method. The latter is not called when the user emptied the autocomplete field. Therefore the flag remains 'false'. And that you can check in the action method of your command button.
I hope it helps someone.