public UpdateCostCategoryDefinitionRequest withEffectiveStart(String effectiveStart) {
        setEffectiveStart(effectiveStart);
        return this;
    }
<p>
The Cost Category's effective start date. It can only be a billing start date (first day of the month). If the
date isn't provided, it's the first day of the current month. Dates can't be before the previous twelve months,
or in the future.
</p>

@param effectiveStart
       The Cost Category's effective start date. It can only be a billing start date (first day of the month). If
       the date isn't provided, it's the first day of the current month. Dates can't be before the previous
       twelve months, or in the future.
@return Returns a reference to this object so that method calls can be chained together.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/UpdateCostCategoryDefinitionRequest.java