Bug 182061 Data engine changes to support result set sharing
data/org.eclipse.birt.data/src/org/eclipse/birt/data/engine/impl/PreparedQuery.java
boolean afterGroup, boolean isDetailedRow, Context cx ) throws DataException
	{
	    if ( expressions == null )
	        return;
	    
	    AggregateRegistry reg = this.aggrTable.getAggrRegistry( groupLevel,
	    		-1,
				isDetailedRow,
				cx );
	    Iterator it = expressions.iterator();
	    while ( it.hasNext() )
	    {
	        prepareExpression((IBaseExpression) it.next(), groupLevel, cx, reg);
	    }
	}
	
	/**
	 * Prepares one expression
	 * 
	 * @param expr
	 * @param groupLevel
	 * @param cx
	 * @param reg
	 */
	private void prepareExpression( IBaseExpression expr, int groupLevel,
			Context cx, AggregateRegistry reg )
	{
	    ExpressionCompiler compiler = this.expressionCompiler;
	    
	    if ( expr instanceof IScriptExpression )