Bug 155262 Total.countDistinct() method returns null on empty resultset
If you use Total.countDistinct(row.aColumn, null, 0) or Total.countDistinct(dataSetRow.aColumn, null, 0) and the resultset for the dataset is empty, the method returns null. It should return 0.
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/aggregation/JSAggrValueObject.java
{
	private int aggrCount;
	private List aggrExprInfoList;
	private IResultIterator odiResult;
	private List[] aggrValues;
	
	
	private static final long serialVersionUID = 1L;
	
	/**
	 * @param aggrExprInfoList
	 * @param odiResult
	 * @param aggrValues