public void setRules(java.util.Collection<CostCategoryRule> rules) {
        if (rules == null) {
            this.rules = null;
            return;
        }

        this.rules = new java.util.ArrayList<CostCategoryRule>(rules);
    }
<p>
The rules are processed in order. If there are multiple rules that match the line item, then the first rule to
match is used to determine that Cost Category value.
</p>

@param rules
       The rules are processed in order. If there are multiple rules that match the line item, then the first
       rule to match is used to determine that Cost Category value.
aws-java-sdk-costexplorer/src/main/java/com/amazonaws/services/costexplorer/model/CostCategory.java