/*
* eXist Open Source Native XML Database
* Copyright (C) 2001- 2017 The eXist Project
* http://exist-db.org
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
package org.exist.xquery.functions.fn;
import org.exist.dom.QName;
import org.exist.numbering.NodeId;
import org.exist.xquery.*;
import org.exist.xquery.value.*;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
public class FnOuterMost extends BasicFunction {
public final static FunctionSignature FNS_OUTERMOST = new FunctionSignature(
new QName("outermost", Function.BUILTIN_FUNCTION_NS),
"Returns every node within the input sequence that has no ancestor that is itself a member of the input sequence; the nodes are returned in document order with duplicates eliminated.",
new SequenceType[] {
new FunctionParameterSequenceType("nodes", Type.NODE, Cardinality.ZERO_OR_MORE, "The nodes to test")
},
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_MORE, "The nodes that have no ancestor which is itself in the input sequence")
);
public FnOuterMost(final XQueryContext context, final FunctionSignature signature) {
super(context, signature);
}
@Override
public Sequence eval(final Sequence[] args, final Sequence contextSequence) throws XPathException {
final Sequence nodes = args[0];
if(nodes.isEmpty()) {
return Sequence.EMPTY_SEQUENCE;
} else if(nodes.hasOne()) {
return nodes;
} else {
final Sequence results = new ValueSequence();
final List<NodeId> nodeIds = getNodeIds(nodes);
final Set<NodeId> found = new HashSet<>();
final SequenceIterator it = nodes.iterate();
while(it.hasNext()) {
final Item item = it.nextItem();
final NodeValue node = ((NodeValue)item);
final NodeId currentNodeId = node.getNodeId();
if(!found.contains(currentNodeId) &&
nodeIds.parallelStream().noneMatch(nodeId -> currentNodeId.isDescendantOf(nodeId))) {
results.add(node);
found.add(currentNodeId);
}
}
return results;
}
}
private List<NodeId> getNodeIds(final Sequence nodes) throws XPathException {
final List<NodeId> nodeIds = new ArrayList<>();
final SequenceIterator it = nodes.iterate();
while(it.hasNext()) {
final Item item = it.nextItem();
final NodeValue node = ((NodeValue)item);
nodeIds.add(node.getNodeId());
}
return nodeIds;
}
}