public AssumeRoleRequest withSerialNumber(String serialNumber) {
        setSerialNumber(serialNumber);
        return this;
    }
<p>
The identification number of the MFA device that is associated with the user who is making the
<code>AssumeRole</code> call. Specify this value if the trust policy of the role being assumed includes a
condition that requires MFA authentication. The value is either the serial number for a hardware device (such as
<code>GAHT12345678</code>) or an Amazon Resource Name (ARN) for a virtual device (such as
<code>arn:aws:iam::123456789012:mfa/user</code>).
</p>
<p>
The regex used to validate this parameter is a string of characters consisting of upper- and lower-case
alphanumeric characters with no spaces. You can also include underscores or any of the following characters: =,.@-
</p>

@param serialNumber
       The identification number of the MFA device that is associated with the user who is making the
       <code>AssumeRole</code> call. Specify this value if the trust policy of the role being assumed includes a
       condition that requires MFA authentication. The value is either the serial number for a hardware device
       (such as <code>GAHT12345678</code>) or an Amazon Resource Name (ARN) for a virtual device (such as
       <code>arn:aws:iam::123456789012:mfa/user</code>).</p>
       <p>
       The regex used to validate this parameter is a string of characters consisting of upper- and lower-case
       alphanumeric characters with no spaces. You can also include underscores or any of the following
       characters: =,.@-
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-sts/src/main/java/com/amazonaws/services/securitytoken/model/AssumeRoleRequest.java