import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
public OrderByModifier(final TupleExpr tupleExpr, final Order order) {
	_tupleExpr = tupleExpr;
	_order = order;
	_variables = new HashMap<Var, Boolean>();

	List<OrderElem> elems = order.getElements();
	Iterator<OrderElem> iter = elems.iterator();

	while (iter.hasNext()) {
		OrderElem ele = iter.next();
		boolean ascending = ele.isAscending();
		ValueExpr ex = ele.getExpr();

		if (ex instanceof Var) {
			_variables.put((Var) ex, new Boolean(ascending));
		}
	}
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
private Query(//
        final QueryModelNode root, //
        final Form form, //
        @Nullable final Modifier modifier, //
        @Nullable final Iterable<? extends ProjectionElem> selectist, //
        @Nullable final TupleExpr construct, //
        @Nullable final Dataset from, //
        final TupleExpr where, //
        @Nullable final Iterable<? extends ProjectionElem> groupByt, //
        @Nullable final ValueExpr having, //
        @Nullable final Iterable<? extends OrderElem> orderBy, //
        @Nullable final Long offset, //
        @Nullable final Long limit) {

    this.root = Preconditions.checkNotNull(root);
    this.form = Preconditions.checkNotNull(form);
    this.modifier = modifier;
    this.select = selectist == null ? ImmutableList.<ProjectionElem>of() : ImmutableList
            .copyOf(selectist);
    this.construct = construct;
    this.from = from;
    this.where = Preconditions.checkNotNull(where);
    this.groupBy = groupByt == null ? ImmutableList.<ProjectionElem>of() : ImmutableList
            .copyOf(groupByt);
    this.having = having;
    this.orderBy = orderBy == null ? ImmutableList.<OrderElem>of() : ImmutableList
            .copyOf(orderBy);
    this.offset = offset;
    this.limit = limit;
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
@Override
public void meet(OrderElem node) throws RuntimeException {
	setSeen(node);
	super.meet(node);
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
@Override
public void meet(OrderElem node) throws RuntimeException {
	check(node);
	super.meet(node);
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
@Override
public void meet(final OrderElem n) {
    emit(n.isAscending() ? "ASC(" : "DESC(").emit(n.getExpr()).emit(")");
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
@Override
public void meet(OrderElem arg0) throws Exception {
	arg0.visitChildren(this);
}
 

import org.openrdf.query.algebra.OrderElem; //导入依赖的package包/类
@Override
public void meet(OrderElem arg0) throws SparqlParserException
{
   // NO-OP
}