@SuppressWarnings("unchecked")
    public void add(Object[] row) {
        int i = 0;
        for (GroupCollector groupCollector : groupCollectors) {
            groupCollector.add(row[i]);
            i++;
        }
    }
Default implementation of the Group interface

@author sasa
@author tiwe
querydsl-core/src/main/java/com/querydsl/core/group/GroupImpl.java