How to indicate a specific Serializer for an object? - json

Question

I have a model like :
SomeModel
public Long id;
public String name;
public Integer age;
public String address;
public Profile profile;
In my templates, I'd like to render a simpler version of this model, only id and name.
If I do Json.toJson(SomeModel.find.findList()); it will render a list of the SomeModels in the database, but with the complete form.
I've written a Serializer that just returns id and name, but how can I tell Json.toJson to use this serializer ?
public class SimpleSomeModelSeralizer extends JsonSerializer<SomeModel> {
#Override
public void serialize(SomeModel someModel, JsonGenerator generator, SerializerProvider serializer) throws IOException,JsonProcessingException {
if (someModel == null) return;
generator.writeStartObject();
generator.writeNumberField("id", someModel.getId());
generator.writeStringField("name", someModel.getName());
generator.writeEndObject();
}
}
I've looked at the code in Play, and of course, toJson is a simple version, that doesn't take some serializer as parameter, so I guess I have to write a longer code, but I don't know what/how to do it.
Code in Play of Json.toJson :
public static JsonNode toJson(final Object data) {
try {
return new ObjectMapper().valueToTree(data);
} catch(Exception e) {
throw new RuntimeException(e);
}
}
Is it possible to do something like this? :
new ObjectMapper().useSerializer(SimpleSomeModelSeralizer.class).valueToTree(SomeModel.find.findList());

Answer 1

Ok so, here's what I did. On the SomeModel class, I added a static method that returns the list as JsonNode, and I simply call it from my templates :
public static JsonNode findItemsAsJson() {
ObjectMapper mapper = new ObjectMapper();
SimpleModule someModelModule = new SimpleModule("SomeModel", new Version(1, 0, 0, null));
someModelModule.addSerializer(SomeModel.class, new SimpleSomeModelSeralizer());
mapper.registerModule(someModelModule);
return mapper.valueToTree(SomeModel.find.findList());
}
The drawback of this method is that you are bound to the query hard coded (SomeModel.find.findList()) but you can easily add a parameter to that method that is the query :
public static JsonNode findItemsAsJson(Query<SomeModel> query) {
ObjectMapper mapper = new ObjectMapper();
SimpleModule someModelModule = new SimpleModule("SomeModel", new Version(1, 0, 0, null));
someModelModule.addSerializer(SomeModel.class, new SimpleSomeModelSeralizer());
mapper.registerModule(someModelModule);
return mapper.valueToTree(query.findList());
}
And you call it with :
SomeModel.findItemsAsJson(SomeModel.find.like("name", "B%").query());
Hope it'll helps :)