JsonFormat.java 文件源码

/** Prints google.protobuf.Value */
private void printValue(MessageOrBuilder message) throws IOException {
  // For a Value message, only the value of the field is formatted.
  Map<FieldDescriptor, Object> fields = message.getAllFields();
  if (fields.isEmpty()) {
    // No value set.
    generator.print("null");
    return;
  }
  // A Value message can only have at most one field set (it only contains
  // an oneof).
  if (fields.size() != 1) {
    throw new InvalidProtocolBufferException("Invalid Value type.");
  }
  for (Map.Entry<FieldDescriptor, Object> entry : fields.entrySet()) {
    printSingleFieldValue(entry.getKey(), entry.getValue());
  }
}