public SavingsPlan withUpfrontPaymentAmount(String upfrontPaymentAmount) {
        setUpfrontPaymentAmount(upfrontPaymentAmount);
        return this;
    }
<p>
The up-front payment amount.
</p>

@param upfrontPaymentAmount
       The up-front payment amount.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-savingsplans/src/main/java/com/amazonaws/services/savingsplans/model/SavingsPlan.java