@Override
  public boolean equals(Object other) {
    if (other instanceof StatementOperation) {
      StatementOperation o = (StatementOperation) other;

      return ObjectUtil.nullEquals(getSubject(), o.getSubject())
          && ObjectUtil.nullEquals(getPredicate(), o.getPredicate())
          && ObjectUtil.nullEquals(getObject(), o.getObject())
          && super.equals(other);
    }

    return false;
  }