public void setDuration(String duration) {
        this.duration = duration;
    }
<p>
Duration filter value, specified in years or seconds. Specify this parameter to show only reservations for this
duration.
</p>
<p>
Valid Values: <code>1 | 3 | 31536000 | 94608000</code>
</p>

@param duration
       Duration filter value, specified in years or seconds. Specify this parameter to show only reservations for
       this duration.</p>
       <p>
       Valid Values: <code>1 | 3 | 31536000 | 94608000</code>
aws-java-sdk-rds/src/main/java/com/amazonaws/services/rds/model/DescribeReservedDBInstancesOfferingsRequest.java