trait QueryConditionTrait in Drupal 8

trait QueryConditionTrait {

  /**
   * The condition object for this query.
   *
   * Condition handling is handled via composition.
   *
   * @var \Drupal\Core\Database\Query\Condition
   */
  protected $condition;

  /**
   * {@inheritdoc}
   */
  public function condition($field, $value = NULL, $operator = '=') {
    $this->condition
      ->condition($field, $value, $operator);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function isNull($field) {
    $this->condition
      ->isNull($field);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function isNotNull($field) {
    $this->condition
      ->isNotNull($field);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function exists(SelectInterface $select) {
    $this->condition
      ->exists($select);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function notExists(SelectInterface $select) {
    $this->condition
      ->notExists($select);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function alwaysFalse() {
    $this->condition
      ->alwaysFalse();
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function &conditions() {
    return $this->condition
      ->conditions();
  }

  /**
   * {@inheritdoc}
   */
  public function arguments() {
    return $this->condition
      ->arguments();
  }

  /**
   * {@inheritdoc}
   */
  public function where($snippet, $args = []) {
    $this->condition
      ->where($snippet, $args);
    return $this;
  }

  /**
   * {@inheritdoc}
   */
  public function compile(Connection $connection, PlaceholderInterface $queryPlaceholder) {
    $this->condition
      ->compile($connection, $queryPlaceholder);
  }

  /**
   * {@inheritdoc}
   */
  public function compiled() {
    return $this->condition
      ->compiled();
  }

  /**
   * {@inheritdoc}
   */
  public function conditionGroupFactory($conjunction = 'AND') {
    return $this->connection
      ->condition($conjunction);
  }

  /**
   * {@inheritdoc}
   */
  public function andConditionGroup() {
    return $this
      ->conditionGroupFactory('AND');
  }

  /**
   * {@inheritdoc}
   */
  public function orConditionGroup() {
    return $this
      ->conditionGroupFactory('OR');
  }

}