Primefaces OrderList and Converter: getAsObject() called with "[object Object]" String - jsf

Question

This can be seen as a continuation of my other question.
In my backend view, I have a list of some POJO. The POJO is converted to JSON with its toString() method:
BackingView.java
#Getter #Setter private List<SomePOJO> pojoList = ...
SomePojo.java
#EqualsAndHashCode(callSuper = false, of = {"id"})
public class SomePOJO implements Serializable {
private static final long serialVersionUID = 1L;
#Getter #Setter private Long id;
#Getter #Setter private Long date;
#Getter #Setter private Date name;
....
#Override
public String toString() {
ObjectMapper mapper = new ObjectMapper();
try {
return mapper.writeValueAsString(this);
} catch (JsonProcessingException e) {
e.printStackTrace();
return null;
}
}
//making a readable string-representation of the object to display on the orderList
public String toStringOrderlistDisplay() {
return "Pojo with id " + id + "and so on... "
}
In my frontend, I want to allow the user to sort this pojo-list using Primefaces orderList :
<p:orderList id="ordList" widgetVar="ordList"
value="#{backingview.pojoList }" var="rfg"
controlsLocation="left" responsive="true" itemValue="#{rfg}"
itemLabel="#{rfg.toStringOrderlistDisplay()}" converter="#{pojoConverter}">
</p:orderList>
PojoConverter.java
#Named
#FacesConverter(value = "pojoConverter")
public class PojoConverter implements Converter {
#Override
public Pojo getAsObject(FacesContext context, UIComponent component, String value) {
if (value != null && value.trim().length() > 0) {
try {
ObjectMapper mapper = new ObjectMapper();
return mapper.readValue(value, RechtsaktFallgeschichte.class);
}
catch (NumberFormatException | IOException ex) {
ex.printStackTrace();
throw new ConverterException(new FacesMessage(FacesMessage.SEVERITY_ERROR, "Conversion Error", "Not a valid Pojo."));
}
}
else { return null; }
}
#Override
public String getAsString(FacesContext context, UIComponent component, Object value) {
SomePOJO r = (SomePOJO) value;
if (r != null) {
return r.toString();
}
else { return null; }
}
}
Converting to JSON seems to work just fine, if I print the output of the getAsString() method, everything looks as you would expect. However, when the getAsObject() method is called, the value-String-parameter always contains "[object Object]" instead of the POJOs JSON representation. What am I doing wrong here?

Answer 1

I don't know if it is possible to achieve what you are trying to do, but a better way (and the working one) is to pass the POJO id in the getAsString() method, and convert it back to Pojo using a cache map Map<Long, Pojo> pojoCache.
The converter should look like this:
PojoConverter.java
#Named
#FacesConverter(value = "pojoConverter")
public class PojoConverter implements Converter<Pojo> {
#Inject
private PojoService pojoService;
#Override
public Pojo getAsObject(FacesContext context, UIComponent component, String value) {
if (value != null && value.trim().length() > 0) {
return pojoService.getPojoCache().get(Long.valueOf(value));
} else {
return null;
}
}
#Override
public String getAsString(FacesContext context, UIComponent component, Pojo value) {
if (value != null) {
return String.valueOf(value.getId());
} else {
return null;
}}
}
For a more detailed explanation check this: p:orderList converter getAsObject() doesn't call Object.toString()