public void setGroupBy(java.util.Collection<DimensionField> groupBy) {
        if (groupBy == null) {
            this.groupBy = null;
            return;
        }

        this.groupBy = new java.util.ArrayList<DimensionField>(groupBy);
    }
<p>
The group by field well of a word cloud. Values are grouped by group by fields.
</p>

@param groupBy
       The group by field well of a word cloud. Values are grouped by group by fields.
aws-java-sdk-quicksight/src/main/java/com/amazonaws/services/quicksight/model/WordCloudAggregatedFieldWells.java