public void setId(String id) {
        this.id = id;
    }
<p>
A short name used to tie this object to the results in the response. This name must be unique within a single
call to <code>GetMetricData</code>. If you are performing math expressions on this set of data, this name
represents that data and can serve as a variable in the mathematical expression. The valid characters are
letters, numbers, and underscore. The first character must be a lowercase letter.
</p>

@param id
       A short name used to tie this object to the results in the response. This name must be unique within a
       single call to <code>GetMetricData</code>. If you are performing math expressions on this set of data,
       this name represents that data and can serve as a variable in the mathematical expression. The valid
       characters are letters, numbers, and underscore. The first character must be a lowercase letter.
aws-java-sdk-cloudwatch/src/main/java/com/amazonaws/services/cloudwatch/model/MetricDataQuery.java