JSF 2 convertNumber permille - jsf

Question

We have a #{object.amount} equal to 0.003 and we would like to display it as 3‰ (With the permille operator)
We also would like to convert the value of an inputText to permille. (e.g: a user input of 3 will store 0.003)
The f:convertNumber allow us to convert to the type % but not ‰ :
<h:outputText value="#{object.amount}" >
<f:convertNumber type="percent" />
</h:outputText>
How can we display a value permille in an outputText and convert a value to a permille in an inputText ?

Answer 1

Like Kukeltje suggested, you can implement a custom converter, for example:
#FacesConverter("permilleConverter")
public class PermilleConverter implements Converter {
private static final String PERMILLE_SYMBOL = "‰";
private static final int PERMILLE_FACTOR = 1000;
#Override
public Object getAsObject(FacesContext context, UIComponent component, String value) {
if (value == null) {
return null;
}
return getDoubleValue(value) / PERMILLE_FACTOR;
}
private Double getDoubleValue(String value) {
NumberFormat nf = new DecimalFormat();
Double doubleValue;
try {
Number number = nf.parse(value);
doubleValue = number.doubleValue();
} catch (ParseException e) {
throw new ConverterException("no valid format");
}
return doubleValue;
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
if (value == null) {
return null;
}
double amount = (double) value;
NumberFormat nf = new DecimalFormat();
nf.setMaximumFractionDigits(0);
return nf.format(amount * PERMILLE_FACTOR) + PERMILLE_SYMBOL;
}
}
And use it like this:
<h:form>
<h:outputText value="#{userBean.amount}">
<f:converter converterId="permilleConverter" />
</h:outputText>
<h:inputText value="#{userBean.amount}">
<f:converter converterId="permilleConverter" />
</h:inputText>
<h:commandButton value="test">
<f:ajax execute="#form" render="#form" />
</h:commandButton>
</h:form>