public function createField($fieldType, $name = null, $required = false)
{
$fieldPosition = $this->getActualFieldPosition();
$name = $name == null ? $fieldType : $name;
$fieldCreateStruct = $this->contentTypeService->newFieldDefinitionCreateStruct($name, $this->fieldTypeInternalIdentifier[$fieldType]);
$fieldCreateStruct->names = array(self::DEFAULT_LANGUAGE => $name);
$fieldCreateStruct->position = $fieldPosition;
$fieldCreateStruct->isRequired = $required;
$fieldCreateStruct->defaultValue = $this->defaultValues[$fieldType];
$this->fieldConstructionObject['fieldType'] = $fieldCreateStruct;
$this->fieldConstructionObject['objectState'] = self::FIELD_TYPE_CREATED;
}