public RestoreDBInstanceFromS3Request withMasterUsername(String masterUsername) {
        setMasterUsername(masterUsername);
        return this;
    }
<p>
The name for the master user.
</p>
<p>
Constraints:
</p>
<ul>
<li>
<p>
Must be 1 to 16 letters or numbers.
</p>
</li>
<li>
<p>
First character must be a letter.
</p>
</li>
<li>
<p>
Can't be a reserved word for the chosen database engine.
</p>
</li>
</ul>

@param masterUsername
       The name for the master user.</p>
       <p>
       Constraints:
       </p>
       <ul>
       <li>
       <p>
       Must be 1 to 16 letters or numbers.
       </p>
       </li>
       <li>
       <p>
       First character must be a letter.
       </p>
       </li>
       <li>
       <p>
       Can't be a reserved word for the chosen database engine.
       </p>
       </li>
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/model/RestoreDBInstanceFromS3Request.java