/*
* 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 org.exist.dom.DocumentSet;
import org.exist.dom.NodeSet;
import org.exist.dom.QName;
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.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.StringValue;
import org.exist.xquery.value.Type;
import org.exist.xquery.value.ValueSequence;
/**
* @author Wolfgang Meier (wolfgang@exist-db.org)
*/
public class FuzzyIndexTerms extends BasicFunction {
public final static FunctionSignature signature = new FunctionSignature(
new QName("fuzzy-index-terms", TextModule.NAMESPACE_URI, TextModule.PREFIX),
"Compares the specified argument against the contents of the fulltext index. Returns " +
"a sequence of strings which are similar to the argument. Similarity is based on Levenshtein " +
"distance. This function may not be useful in its current form and is subject to change.",
new SequenceType[]{
new FunctionParameterSequenceType("term", Type.STRING, Cardinality.ZERO_OR_ONE, "The term")},
new FunctionReturnSequenceType(Type.STRING, Cardinality.ZERO_OR_MORE, "a sequence of strings which are similar to the argument $term"));
public FuzzyIndexTerms(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 {
if(args[0].isEmpty())
{return Sequence.EMPTY_SEQUENCE;}
DocumentSet docs;
if(contextSequence instanceof NodeSet)
{docs = contextSequence.getDocumentSet();}
else
{docs = context.getStaticallyKnownDocuments();}
final String term = args[0].getStringValue();
final String[] matches =
context.getBroker().getTextEngine().getIndexTerms(docs, new FuzzyMatcher(term, 0.65));
final ValueSequence result = new ValueSequence();
for(int i = 0; i < matches.length; i++)
result.add(new StringValue(matches[i]));
return result;
}
}