package ejava.util.json;
   
   import java.io.InputStream;
   
   import javax.json.bind.Jsonb;
   import javax.json.bind.JsonbBuilder;
   import javax.json.bind.JsonbConfig;
   import javax.json.bind.config.PropertyNamingStrategy;
   
  public class JsonbUtil {
      static Jsonb getContext(Class<?> type) {
          JsonbConfig config=new JsonbConfig();
          //config.setProperty(JsonbConfig.FORMATTING, true);
          config.setProperty(JsonbConfig.PROPERTY_NAMING_STRATEGY, PropertyNamingStrategy.LOWER_CASE_WITH_UNDERSCORES);
          //config.setProperty(JsonbConfig.NULL_VALUES, true); //helps us spot fields we don't want
          return JsonbBuilder.create(config);
      }
  
      public static <T> String marshal(T object) {
          if (object==null) {
              return "";
          }
          
          Jsonb jsb = getContext(object.getClass());
          String jsonString = jsb.toJson(object);
          return jsonString;        
      }
      
      public static <T> T unmarshal(String string, Class<T> type) {
          if (string==null || string.isEmpty()) {
              return null;
          }
          
          Jsonb jsb = getContext(type);
          T object = (T) jsb.fromJson(string, type);
          return object;
      }
      
      public static <T> T unmarshall(InputStream is, Class<T> type) {
          if (is==null) {
              return null;
          }
          
          Jsonb jsb = getContext(type);
          T object = (T) jsb.fromJson(is, type);
          return object;
      }
  }