Example generated code

InterfaceParentUUT__JsonHelper.java

package com.instagram.common.json.annotation.processor.parent;

import com.fasterxml.jackson.core.JsonGenerator;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.core.JsonToken;
import com.instagram.common.json.JsonFactoryHolder;
import com.instagram.common.json.JsonHelper;
import com.instagram.common.json.JsonSerializationHandler;
import java.io.IOException;
import java.util.HashMap;
import javax.annotation.Nullable;

public final class InterfaceParentUUT__JsonHelper
    implements JsonHelper<InterfaceParentUUT> {
  private static final HashMap<String,JsonSerializationHandler<InterfaceParentUUT>> sHandlerMap = new HashMap<>();

  public static void registerHandler(String typeName, JsonSerializationHandler<InterfaceParentUUT> handler) {
    if (sHandlerMap.containsKey(typeName)) {
      final String message = String.format(
          "Duplicate handler type name. %s is already mapped to an instance of %s",
          typeName,
          sHandlerMap.get(typeName).getClass().getName());
      throw new IllegalArgumentException(message);
    }
    sHandlerMap.put(typeName, handler);
  }

  public static void unregisterHandler(String typeName) {
    sHandlerMap.remove(typeName);
  }

  private static JsonSerializationHandler<InterfaceParentUUT> getHandler(String typeName) {
    final @Nullable JsonSerializationHandler<InterfaceParentUUT> handler = sHandlerMap.get(typeName);
    if (handler == null) {
      final String message = String.format(
          "No JsonSerializationHandler registered for type name: %s",
          typeName);
      throw new IllegalArgumentException(message);
    }

    return handler;
  }

  public static InterfaceParentUUT parseFromJson(JsonParser parser)
      throws IOException {
    if (parser.getCurrentToken() != JsonToken.START_ARRAY) {
      parser.skipChildren();
    }

    parser.nextToken();
    if (parser.getCurrentToken() != JsonToken.VALUE_STRING) {
      parser.skipChildren();
    }

    String typeName = parser.getText();
    parser.nextToken();
    final InterfaceParentUUT instance = getHandler(typeName).parseFromJson(parser);
    parser.nextToken();
    return instance;
  }

  public static InterfaceParentUUT parseFromJson(String inputString)
      throws IOException {
    JsonParser jp = JsonFactoryHolder.APP_FACTORY.createParser(inputString);
    jp.nextToken();
    return parseFromJson(jp);
  }

  // writeStartAndEnd is included for API compatibility, but is ignored.
  public static void serializeToJson(JsonGenerator generator, InterfaceParentUUT object, boolean writeStartAndEndIgnored)
      throws IOException {
    generator.writeStartArray();
    generator.writeString(object.getTypeNameYeah());
    getHandler(object.getTypeNameYeah()).serializeToJson(generator, object);
    generator.writeEndArray();
  }
}