Examples with OrderExpression org.datanucleus.store.query.expression.OrderExpression used on opensource projects

Example 1 with OrderExpression

use of org.datanucleus.store.query.expression.OrderExpression in project datanucleus-rdbms by datanucleus.

the class QueryToSQLMapper method compileOrdering.

/**
 * Method to compile the ordering clause of the query into the SQLStatement.
 * @param stmt SELECT statement
 */
protected void compileOrdering(SelectStatement stmt) {
    if (compilation.getExprOrdering() != null) {
        compileComponent = CompilationComponent.ORDERING;
        Expression[] orderingExpr = compilation.getExprOrdering();
        SQLExpression[] orderSqlExprs = new SQLExpression[orderingExpr.length];
        boolean[] directions = new boolean[orderingExpr.length];
        NullOrderingType[] nullOrders = new NullOrderingType[orderingExpr.length];
        for (int i = 0; i < orderingExpr.length; i++) {
            OrderExpression orderExpr = (OrderExpression) orderingExpr[i];
            Expression expr = orderExpr.getLeft();
            if (expr instanceof PrimaryExpression) {
                PrimaryExpression orderPrimExpr = (PrimaryExpression) expr;
                if (orderPrimExpr.getTuples().size() == 1 && resultAliases != null) {
                    if (resultAliases.contains(orderPrimExpr.getId().toLowerCase())) {
                        // Order by a result alias
                        orderSqlExprs[i] = new ResultAliasExpression(stmt, orderPrimExpr.getId());
                    }
                }
            }
            if (orderSqlExprs[i] == null) {
                orderSqlExprs[i] = (SQLExpression) orderExpr.getLeft().evaluate(this);
            }
            String orderDir = orderExpr.getSortOrder();
            directions[i] = ((orderDir == null || orderDir.equals("ascending")) ? false : true);
            nullOrders[i] = orderExpr.getNullOrder();
        }
        stmt.setOrdering(orderSqlExprs, directions, nullOrders);
        compileComponent = null;
    }
}