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 AggrExprInfo getAggrInfo( int i )
	{
		return (AggrExprInfo) this.aggrExprInfoList.get( i );
	}
	
	/**
	 * Get aggregation's count
	 * @return
	 */
	int getAggrCount( )
	{
		return this.aggrExprInfoList.size( );
	}
	/**
	 * Get the aggregate value list.
	 * 
	 * @param i
	 * @return
	 */
	public List getAggregateValues( int i )
	{
		if( i < this.aggrCount )
			return aggrValues[i];
		else
			return null;
	}
	
}