a proposition of a DtoJsonStringHelper

DtoJsonStringHelper.java

public class DtoJsonStringHelper {
	private DtoJsonStringHelper() {
	}

	private static final Gson GSON = new GsonBuilder()
			.registerTypeAdapter(Optional.class, new GsonOptionalDeserializer())
			.registerTypeAdapter(List.class, new GsonListDeserializer())
			.create();

	private static class GsonOptionalDeserializer implements JsonSerializer<Optional<?>> {

		@Override
		public JsonElement serialize(Optional<?> src, Type typeOfSrc, JsonSerializationContext context) {
			final JsonElement element = context.serialize(src.toString());
			final JsonArray result = new JsonArray();
			result.add(element);
			return result;
		}
	}

	private static class GsonListDeserializer implements JsonSerializer<List<?>> {

		@Override
		public JsonElement serialize(List<?> src, Type typeOfSrc, JsonSerializationContext context) {
			String value;
			if (src.size() > 1000){
				value = "trop long";
			}else{
				value = src.toString();
			}
			final JsonElement element = context.serialize(value);
			final JsonArray result = new JsonArray();
			result.add(element);
			return result;
		}
	}
	
	
	public static String toString(Object o) {
		Preconditions.checkNotNull(o);
		return o.getClass().getSimpleName() + GSON.toJson(o);
	}

}