public void setMetricName(String metricName) {
        this.metricName = metricName;
    }
<p>
A friendly name or description for the metrics for this <code>WebACL</code>. The name can contain only
alphanumeric characters (A-Z, a-z, 0-9), with maximum length 128 and minimum length one. It can't contain
whitespace or metric names reserved for AWS WAF, including "All" and "Default_Action." You can't change
<code>MetricName</code> after you create the <code>WebACL</code>.
</p>

@param metricName
       A friendly name or description for the metrics for this <code>WebACL</code>. The name can contain only
       alphanumeric characters (A-Z, a-z, 0-9), with maximum length 128 and minimum length one. It can't contain
       whitespace or metric names reserved for AWS WAF, including "All" and "Default_Action." You can't change
       <code>MetricName</code> after you create the <code>WebACL</code>.
aws-java-sdk-waf/src/main/java/com/amazonaws/services/waf/model/WebACL.java