assert scriptExpr != null;
assert exprText != null;
	private void validateSelectedColumns( IBaseQueryDefinition query )			throws EngineException	{		assert query != null;		Collection exprs = query.getRowExpressions( );		if ( selectedColumns != null )		{			for ( int i = 0; i < selectedColumns.length; i++ )			{				boolean findColumn = false;				Iterator iter = exprs.iterator( );				while ( iter.hasNext( ) )				{					IBaseExpression expr = (IBaseExpression) iter.next( );					IScriptExpression scriptExpr = null;					if ( expr instanceof IConditionalExpression )					{						IConditionalExpression condExpr = ( IConditionalExpression ) expr;						scriptExpr = condExpr.getExpression( );					}					else if ( expr instanceof IScriptExpression )					{						scriptExpr = ( IScriptExpression ) expr;					}										assert scriptExpr != null;										if ( scriptExpr.getText( ).equalsIgnoreCase( selectedColumns[i] ) )					{						findColumn = true;						break;					}				}				if ( findColumn == false )				{					throw new EngineException( "Invalid Columns" );				}			}		}		else		{			if ( exprs.size( ) <= 0 )			{				throw new EngineException( "Can't exported data in groups" );			}			else			{				selectedColumns = new String[exprs.size( )];				Iterator iter = exprs.iterator( );								for ( int i = 0; i < selectedColumns.length; i++ )				{					IBaseExpression expr = (IBaseExpression) iter.next( );					if ( expr instanceof IConditionalExpression )					{						IConditionalExpression condExpr = (IConditionalExpression) expr;						selectedColumns[i] = condExpr.getExpression( ).getText( );					}					else if ( expr instanceof IScriptExpression )					{						IScriptExpression scriptExpr = (IScriptExpression) expr;						selectedColumns[i] = scriptExpr.getText( );					}				}			}		} 	}