/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 The eXist Team
*
* 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 program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* $Id$
*/
package org.exist.xquery.functions.util;
import org.apache.log4j.Logger;
import org.exist.dom.DocumentImpl;
import org.exist.dom.NodeProxy;
import org.exist.dom.QName;
import org.exist.memtree.NodeImpl;
import org.exist.numbering.NodeId;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.Cardinality;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* @author wolf
*
*/
public class GetNodeById extends BasicFunction {
protected static final Logger logger = Logger.getLogger(GetNodeById.class);
public final static FunctionSignature signature =
new FunctionSignature(
new QName("node-by-id", UtilModule.NAMESPACE_URI, UtilModule.PREFIX),
"Retrieves a node by its internal node-id. The document is specified via the first " +
"argument. It may either be a document node or another node from the same document " +
"from which the target node will be retrieved by its id. The second argument is " +
"the internal node-id, specified as a string. Please note: the function does " +
"not check if the passed id does really point to an existing node. It just returns " +
"a pointer, which may thus be invalid.",
new SequenceType[] {
new FunctionParameterSequenceType("document", Type.NODE, Cardinality.EXACTLY_ONE, "The document whose node is to be retrieved by its id"),
new FunctionParameterSequenceType("node-id", Type.STRING, Cardinality.EXACTLY_ONE, "The internal node id")
},
new FunctionReturnSequenceType(Type.NODE, Cardinality.EXACTLY_ONE, "the node"));
/**
* @param context
*/
public GetNodeById(XQueryContext context) {
super(context, signature);
}
/* (non-Javadoc)
* @see org.exist.xquery.BasicFunction#eval(org.exist.xquery.value.Sequence[], org.exist.xquery.value.Sequence)
*/
public Sequence eval(Sequence[] args, Sequence contextSequence)
throws XPathException {
final String id = args[1].itemAt(0).getStringValue();
final NodeId nodeId = context.getBroker().getBrokerPool().getNodeFactory().createFromString(id);
final NodeValue docNode = (NodeValue) args[0].itemAt(0);
if (docNode.getImplementationType() == NodeValue.IN_MEMORY_NODE) {
return ((NodeImpl) docNode).getDocument().getNodeById(nodeId);
} else {
final DocumentImpl doc = ((NodeProxy)docNode).getDocument();
return new NodeProxy(doc, nodeId);
}
}
}