/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-07 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
*
* $Id$
*/
package org.exist.versioning.xquery;
import org.exist.xquery.BasicFunction;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.Cardinality;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.XPathException;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.NodeValue;
import org.exist.xquery.value.DateTimeValue;
import org.exist.dom.QName;
import org.exist.dom.DocumentImpl;
import org.exist.dom.NodeProxy;
import org.exist.memtree.MemTreeBuilder;
import org.exist.memtree.DocumentBuilderReceiver;
import org.exist.versioning.VersioningTrigger;
import org.exist.versioning.Diff;
import org.exist.versioning.StandardDiff;
import org.exist.versioning.DiffException;
import org.xml.sax.SAXException;
import java.util.Properties;
import java.util.Date;
public class DiffFunction extends BasicFunction {
public final static FunctionSignature signature =
new FunctionSignature(
new QName( "diff", VersioningModule.NAMESPACE_URI, VersioningModule.PREFIX ),
"Returns a diff between two documents (which normally means two " +
"versions of the same document). Both documents should be stored in the " +
"database. The function will not work with in-memory documents. The returned " +
"diff uses the same format as generated by the VersioningTrigger.",
new SequenceType[] {
new SequenceType(Type.NODE, Cardinality.EXACTLY_ONE),
new SequenceType(Type.NODE, Cardinality.EXACTLY_ONE)
},
new SequenceType( Type.NODE, Cardinality.EXACTLY_ONE )
);
public DiffFunction(XQueryContext context) {
super(context, signature);
}
public Sequence eval(Sequence[] args, Sequence contextSequence) throws XPathException {
NodeValue nv1 = (NodeValue) args[0].itemAt(0);
NodeValue nv2 = (NodeValue) args[1].itemAt(0);
if (nv1.getImplementationType() != NodeValue.PERSISTENT_NODE ||
nv2.getImplementationType() != NodeValue.PERSISTENT_NODE)
throw new XPathException(this, "diff function only works on persistent documents stored in the db");
DocumentImpl doc1 = ((NodeProxy)nv1).getDocument();
DocumentImpl doc2 = ((NodeProxy)nv2).getDocument();
context.pushDocumentContext();
try {
MemTreeBuilder builder = context.getDocumentBuilder();
DocumentBuilderReceiver receiver = new DocumentBuilderReceiver(builder);
Properties properties = new Properties();
properties.setProperty("document", doc1.getURI().toString());
properties.setProperty("revision", "");
properties.setProperty("date", new DateTimeValue(new Date()).getStringValue());
properties.setProperty("user", context.getUser().getName());
int nodeNr = builder.startElement(VersioningTrigger.ELEMENT_VERSION, null);
VersioningTrigger.writeProperties(receiver, properties);
Diff diff = new StandardDiff(context.getBroker());
diff.diff(doc1, doc2);
diff.diff2XML(receiver);
builder.endElement();
return builder.getDocument().getNode(nodeNr);
} catch (SAXException e) {
throw new XPathException(this, "Caugt error while generating diff: " + e.getMessage(), e);
} catch (DiffException e) {
throw new XPathException(this, "Caugt error while generating diff: " + e.getMessage(), e);
} finally {
context.popDocumentContext();
}
}
}