package org.basex.query.expr;
import static org.basex.query.util.Err.*;
import org.basex.query.QueryContext;
import org.basex.query.QueryException;
import org.basex.query.item.Item;
import org.basex.query.item.ANode;
import org.basex.query.item.NodeType;
import org.basex.query.item.SeqType;
import org.basex.query.item.Value;
import org.basex.query.iter.Iter;
import org.basex.query.iter.NodeCache;
import org.basex.util.InputInfo;
/**
* Root node.
*
* @author BaseX Team 2005-12, BSD License
* @author Christian Gruen
*/
public final class Root extends Simple {
/**
* Constructor.
* @param ii input info
*/
public Root(final InputInfo ii) {
super(ii);
type = SeqType.NOD_ZM;
}
@Override
public Iter iter(final QueryContext ctx) throws QueryException {
final Iter iter = checkCtx(ctx).iter();
final NodeCache nc = new NodeCache().random();
for(Item i; (i = iter.next()) != null;) {
final ANode n = root(i);
if(n == null || n.type != NodeType.DOC) CTXNODE.thrw(input);
nc.add(n);
}
return nc;
}
/**
* Returns the root node of the specified item.
* @param v input node
* @return root node
*/
public static ANode root(final Value v) {
if(!v.type.isNode()) return null;
ANode n = (ANode) v;
while(true) {
final ANode p = n.parent();
if(p == null) return n;
n = p;
}
}
@Override
public boolean uses(final Use u) {
return u == Use.CTX;
}
@Override
public boolean iterable() {
return true;
}
@Override
public boolean sameAs(final Expr cmp) {
return cmp instanceof Root;
}
@Override
public String toString() {
return "root()";
}
}