/*
* eXist Open Source Native XML Database
* Copyright (C) 2005-09 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 program; if not, write to the Free Software Foundation
* Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* $Id$
*/
package org.exist.xquery.functions.system;
import java.util.ArrayList;
import java.util.List;
import org.apache.log4j.Logger;
import org.exist.dom.NodeSet;
import org.exist.dom.QName;
import org.exist.storage.DBBroker;
import org.exist.storage.analysis.Tokenizer;
import org.exist.xquery.AnalyzeContextInfo;
import org.exist.xquery.Cardinality;
import org.exist.xquery.Dependency;
import org.exist.xquery.DynamicCardinalityCheck;
import org.exist.xquery.Expression;
import org.exist.xquery.Function;
import org.exist.xquery.FunctionSignature;
import org.exist.xquery.XPathException;
import org.exist.xquery.XQueryContext;
import org.exist.xquery.util.Error;
import org.exist.xquery.value.FunctionReturnSequenceType;
import org.exist.xquery.value.FunctionParameterSequenceType;
import org.exist.xquery.value.Item;
import org.exist.xquery.value.Sequence;
import org.exist.xquery.value.SequenceType;
import org.exist.xquery.value.Type;
public class FtIndexLookup extends Function {
protected final static Logger logger = Logger.getLogger(FtIndexLookup.class);
public final static FunctionSignature signature = new FunctionSignature(
new QName("ft-index-lookup", SystemModule.NAMESPACE_URI, SystemModule.PREFIX),
"Internal function doing old full-text index lookup filtering. Intended to support the query optimizer by allowing restrictive filtering early on.",
new SequenceType[]{
new FunctionParameterSequenceType("nodes", Type.NODE, Cardinality.ZERO_OR_MORE, "The nodes"),
new FunctionParameterSequenceType("string-filter", Type.STRING, Cardinality.ZERO_OR_ONE, "The string-filter")
},
new FunctionReturnSequenceType(Type.NODE, Cardinality.ZERO_OR_MORE, "the nodes matching the string-filter"));
public FtIndexLookup(XQueryContext context) {
super(context, signature);
}
/**
* Overwritten: function can process the whole context sequence at once.
*
* @see org.exist.xquery.Expression#getDependencies()
*/
public int getDependencies() {
return Dependency.CONTEXT_SET;
}
/**
* Overwritten to disable automatic type checks. We check manually.
*
* @see org.exist.xquery.Function#setArguments(java.util.List)
*/
public void setArguments(List<Expression> arguments) throws XPathException {
// wrap arguments into a cardinality check, so an error will be generated if
// one of the arguments returns an empty sequence
Expression arg = arguments.get(0);
arg = new DynamicCardinalityCheck(context, Cardinality.ZERO_OR_MORE, arg,
new Error(Error.FUNC_PARAM_CARDINALITY, "1", mySignature));
steps.add(arg);
arg = arguments.get(1);
arg = new DynamicCardinalityCheck(context, Cardinality.ZERO_OR_MORE, arg,
new Error(Error.FUNC_PARAM_CARDINALITY, "2", mySignature));
steps.add(arg);
}
public void analyze(AnalyzeContextInfo contextInfo) throws XPathException {
contextInfo.setParent(this);
// call analyze for each argument
inPredicate = (contextInfo.getFlags() & IN_PREDICATE) > 0;
for(int i = 0; i < getArgumentCount(); i++) {
getArgument(i).analyze(contextInfo);
}
}
public Sequence eval(Sequence contextSequence, Item contextItem)
throws XPathException {
final Sequence querySeq = getArgument(1).eval(contextSequence);
if (querySeq.isEmpty()) {
return Sequence.EMPTY_SEQUENCE;
}
final String query = querySeq.itemAt(0).getStringValue();
final String[] terms = getSearchTerms(query);
final NodeSet hits[] = new NodeSet[terms.length];
final NodeSet contextSet = contextSequence.toNodeSet();
for (int k = 0; k < terms.length; k++) {
hits[k] =
context.getBroker().getTextEngine().getNodesContaining(
context,
contextSet.getDocumentSet(),
null, NodeSet.DESCENDANT, null,
terms[k],
DBBroker.MATCH_EXACT);
hits[k] = getArgument(0).eval(hits[k]).toNodeSet();
}
NodeSet result = hits[0];
for(int k = 1; k < hits.length; k++) {
if(hits[k] != null)
{result = result.deepIntersection(hits[k]);}
}
logger.debug("FOUND: " + result.getLength());
return result;
}
protected String[] getSearchTerms(String searchString) {
final List<String> tokens = new ArrayList<String>();
final Tokenizer tokenizer =
context.getBroker().getTextEngine().getTokenizer();
tokenizer.setText(searchString);
org.exist.storage.analysis.TextToken token;
String word;
while (null != (token = tokenizer.nextToken(true))) {
word = token.getText();
tokens.add(word);
}
String[] terms = new String[tokens.size()];
terms = tokens.toArray(terms);
return terms;
}
}