package com.dbxml.db.common.xpath;
/*
* dbXML - Native XML Database
* Copyright (c) 1999-2006 The dbXML Group, L.L.C.
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included
* in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*
* $Id: XPathResultSet.java,v 1.7 2006/02/02 18:53:52 bradford Exp $
*/
import com.dbxml.db.common.adapters.DOMAdapter;
import com.dbxml.db.common.query.ResultSetBase;
import com.dbxml.db.core.Collection;
import com.dbxml.db.core.DBException;
import com.dbxml.db.core.data.Key;
import com.dbxml.db.core.query.ProcessingException;
import com.dbxml.db.core.query.Query;
import com.dbxml.db.core.query.QueryException;
import com.dbxml.db.core.transaction.Transaction;
import com.dbxml.xml.SymbolTable;
import com.dbxml.xml.dtsm.DTSMException;
import com.dbxml.xml.dtsm.DTSMHelper;
import com.dbxml.xml.dtsm.DocumentTable;
import org.apache.xml.utils.PrefixResolver;
import org.apache.xml.utils.PrefixResolverDefault;
import org.apache.xpath.XPath;
import org.apache.xpath.XPathContext;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.traversal.NodeIterator;
import com.dbxml.xml.dom.DOMUtils;
import org.w3c.dom.Element;
/**
* XPathResultSet
*/
final class XPathResultSet extends ResultSetBase {
private SymbolTable symbols;
private String xpath;
private PrefixResolver pr;
private XPath xp;
private NodeIterator ni;
private DocumentTable dt;
private DOMAdapter domAdapter;
private Node node;
public XPathResultSet(Transaction tx, Collection context, Query query, Key[] keySet, PrefixResolver pr, String xpath) {
super(tx, context, query, keySet);
this.pr = pr;
this.xpath = xpath;
domAdapter = new DOMAdapter(context);
}
private void prepareNextNode() throws QueryException {
node = null;
while ( nextKey() != null ) {
Transaction tx = new Transaction();
try {
Document d = domAdapter.getDocument(tx, currentKey);
if ( d == null )
continue;
Node n = d.getDocumentElement();
XPathContext xpc = new XPathContext();
PrefixResolver pfx;
if ( pr == null ) {
pfx = new PrefixResolverDefault(d.getDocumentElement());
xp = new XPath(xpath, null, pfx, XPath.SELECT, null);
}
else {
pfx = pr;
if ( xp == null )
xp = new XPath(xpath, null, pfx, XPath.SELECT, null);
}
ni = xp.execute(xpc, n, pfx).nodeset();
node = ni.nextNode();
if ( node != null )
break;
}
catch ( Exception e ) {
try {
tx.cancel();
}
catch ( DBException ex ) {
ex.printStackTrace(System.err);
}
}
finally {
if ( tx.getStatus() == Transaction.ACTIVE ) {
try {
tx.commit();
}
catch ( DBException e ) {
e.printStackTrace(System.err);
}
}
}
}
}
public int getResultType() throws QueryException {
checkOpened();
getResult();
if ( dt != null )
return dt.getEntry(0).getTypeID();
else
return -1;
}
public int getCount() throws QueryException {
checkOpened();
return -1;
}
public boolean next() throws QueryException {
checkOpened();
dt = null;
if ( ni == null )
prepareNextNode();
else {
node = ni.nextNode();
if ( node == null )
prepareNextNode();
}
return node != null;
}
public DocumentTable getResult() throws QueryException {
checkOpened();
if ( dt == null && node != null ) {
try {
if ( node.getNodeType() == Node.ELEMENT_NODE )
DOMUtils.importNamespaces((Element)node);
dt = DTSMHelper.nodeToTable(node, symbols);
}
catch ( DTSMException e ) {
throw new ProcessingException(e);
}
}
return dt;
}
}