How to pass parameter to JsonSerializer?

Question

I have a simple data service :

@GET
public Data getData(@QueryParam("id") Long id) {
  Data data = dataService.getData(id);
  return data;
}

And a matching DataSerializer that implements JsonSerializer<Data> : The DataSerializer is registered to Jackson via :

simpleModule.addSerializer(Data.class , dataSerializer);
ObjectMapper mapper = new ObjectMapper();
mapper.registerModule(simpleModule);

It works well. But today , I want to add another Locale parameter , and hope the DataSerializer to output correspondent content :

@GET
public Data getData(@QueryParam("id") Long id , @QueryParam("locale") Locale locale)

The 'Data' itself contains various locale variations , and I hope to get the assigned locale output.

But when I get the locale from the parameter , I don't know how to pass the locale value to the DataSerializer …

Is there anyway to achieve this ?

Except this solution :

Data data = dataService.getData(id.get() , locale);

which is not what I want.

It seems ThreadLocal is the only way to achieve this , but I feel that is ugly. Any other feasible solutions ?

Thanks.

Environments : dropwizard-0.7.0-rc2 , jackson-core:jar:2.3.1

===================== updated ==========

reply to @andrei-i :

Because my data itself already contains various locale versions. for example :

Data helloData = dataService.get("hello");
helloData.getName(Locale.English) == "Hello";
helloData.getName(Locale.France) == "Bonjour";
helloData.getName(Locale.Germany) == "Hallo";

I want to directly pass the locale from URL to JsonSerializer , to get one version of the data presentation.

And there 'may' be other version (not just locale) , so , inheriting Data mixing Locale is not considered.

Answer 1

I know that this is not a new question but here is what I came up with facing the similar problem:

1. created custom annotation:

   @Target({ ElementType.FIELD, ElementType.TYPE, ElementType.METHOD })
   @Retention(RetentionPolicy.RUNTIME)
   public @interface JsonLocalizable {
   
     public String localizationKey();
   } 
   

2. Jackson serializer:

    public class LocalizingSerializer extends StdSerializer<String> implements ContextualSerializer {
   
         private String localizationKey;
   
         public LocalizingSerializer() {
           super(String.class);
         }
   
         public LocalizingSerializer(String key) {
           super(String.class);
   
           this.localizationKey = key;
         }
   
         @Override
         public void serialize(String value, JsonGenerator jgen, SerializerProvider provider) throws IOException, JsonGenerationException {
   
           String localizedValue = //.... get the value using localizationKey
   
           jgen.writeString(localizedValue);
         }
   
         @Override
         public JsonSerializer<?> createContextual(SerializerProvider prov, BeanProperty property) throws JsonMappingException {
   
           String key = null;
           JsonLocalizable ann = null;
   
           if (property != null) {
             ann = property.getAnnotation(JsonLocalizable.class);
           }
   
           if (ann != null) {
             key = ann.localizationKey();
           }
   
           //if key== null??
   
           return new LocalizingSerializer(key);
         }
       }
   

3. Annotate the field you want to localize:

   public class TestClass {
   
       @JsonSerialize(using = LocalizingSerializer.class)
       @JsonLocalizable(localizationKey = "my.key")
       private String field;
   
       public String getField() {
         return this.field;
       }
   
       public void setField(String field) {
         this.field = field;
       }
   }
   

Answer 2

Solution 1. In your JAX-RS implementation register your own implementation of MessageBodyWriter for JSON requests. Probably your implementation will extend Jackson. Also it might be possible that you will have to unregister Jackson. In a MessageBodyWriter you can inject a UriInfo instance using the @Context annotation, and with it you can get any request parameter.

Solution 2. Change the architecture of your Data, so that it is locale-aware. For example, create a setter setLocale() which will change the returned data, if the locale was set.