/*
* eXist Open Source Native XML Database
* Copyright (C) 2001-09 Wolfgang M. Meier
* wolfgang@exist-db.org
* http://exist.sourceforge.net
*
* 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.text;
import java.util.List;
import org.exist.dom.NodeSet;
import org.exist.dom.QName;
import org.exist.storage.TermMatcher;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Constants;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.value.DoubleValue;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
/**
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class FuzzyMatchAll extends AbstractMatchFunction {
public final static FunctionSignature signature = new FunctionSignature(
new QName("fuzzy-match-all", TextModule.NAMESPACE_URI, TextModule.PREFIX),
"Fuzzy keyword search, which compares strings based on the Levenshtein distance " +
"(or edit distance). The function tries to match each of the keywords specified in the " +
"keyword string against the string value of each item in the sequence $source.",
new SequenceType[]{
new FunctionParameterSequenceType("source", Type.NODE, Cardinality.ZERO_OR_MORE, "The source"),
new FunctionParameterSequenceType("keyword", Type.STRING, Cardinality.EXACTLY_ONE, "The keyword string")},
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_MORE, "the sequence of nodes that match the keywords"),
true);
public FuzzyMatchAll(XQueryContext context) {
super(context, Constants.FULLTEXT_AND, signature);
}
public FuzzyMatchAll(XQueryContext context, int type, FunctionSignature signature) {
super(context, type, signature);
}
public Sequence evalQuery(NodeSet nodes,
List<String> terms) throws XPathException {
if (terms == null || terms.size() == 0)
{return Sequence.EMPTY_SEQUENCE;} // no search terms
double threshold = 0.65;
if (getArgumentCount() == 3) {
final Sequence thresOpt = getArgument(2).eval(nodes);
//TODO : get rid of getLength()
if(!thresOpt.hasOne())
{throw new XPathException(this, "third argument to " + getName() +
"should be a single double value");}
threshold = ((DoubleValue) thresOpt.convertTo(Type.DOUBLE)).getDouble();
}
final NodeSet hits[] = new NodeSet[terms.size()];
String term;
TermMatcher matcher;
for (int k = 0; k < terms.size(); k++) {
term = terms.get(k);
if(term.length() == 0)
{hits[k] = null;}
else {
matcher = new FuzzyMatcher(term, threshold);
hits[k] =
context.getBroker().getTextEngine().getNodes(
context,
nodes.getDocumentSet(),
nodes, NodeSet.ANCESTOR, null,
matcher, term.substring(0, 1));
}
}
return mergeResults(hits);
}
}