public void setDomain(String domain) {
        this.domain = domain;
    }
<p>
The domain string. For custom domains, this is the fully-qualified domain name, such as
<code>auth.example.com</code>. For Amazon Cognito prefix domains, this is the prefix alone, such as
<code>auth</code>.
</p>

@param domain
       The domain string. For custom domains, this is the fully-qualified domain name, such as
       <code>auth.example.com</code>. For Amazon Cognito prefix domains, this is the prefix alone, such as
       <code>auth</code>.
aws-java-sdk-cognitoidp/src/main/java/com/amazonaws/services/cognitoidp/model/DomainDescriptionType.java