/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.lucene.xmlparser.webdemo;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Enumeration;
import java.util.Properties;
import java.util.StringTokenizer;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.CorruptIndexException;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.xmlparser.CorePlusExtensionsParser;
import org.apache.lucene.xmlparser.QueryTemplateManager;
public class FormBasedXmlQueryDemo extends HttpServlet {
private QueryTemplateManager queryTemplateManager;
private CorePlusExtensionsParser xmlParser;
private IndexSearcher searcher;
private Analyzer analyzer=new StandardAnalyzer(org.apache.lucene.util.Version.LUCENE_CURRENT);
@Override
public void init(ServletConfig config) throws ServletException {
super.init(config);
try {
openExampleIndex();
//load servlet configuration settings
String xslFile=config.getInitParameter("xslFile");
String defaultStandardQueryParserField = config.getInitParameter("defaultStandardQueryParserField");
//Load and cache choice of XSL query template using QueryTemplateManager
queryTemplateManager=new QueryTemplateManager(
getServletContext().getResourceAsStream("/WEB-INF/"+xslFile));
//initialize an XML Query Parser for use by all threads
xmlParser=new CorePlusExtensionsParser(defaultStandardQueryParserField,analyzer);
} catch (Exception e) {
throw new ServletException("Error loading query template",e);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//Take all completed form fields and add to a Properties object
Properties completedFormFields=new Properties();
Enumeration pNames = request.getParameterNames();
while(pNames.hasMoreElements()){
String propName=(String) pNames.nextElement();
String value=request.getParameter(propName);
if((value!=null)&&(value.trim().length()>0)){
completedFormFields.setProperty(propName, value);
}
}
try{
//Create an XML query by populating template with given user criteria
org.w3c.dom.Document xmlQuery=queryTemplateManager.getQueryAsDOM(completedFormFields);
//Parse the XML to produce a Lucene query
Query query=xmlParser.getQuery(xmlQuery.getDocumentElement());
//Run the query
TopDocs topDocs = searcher.search(query,10);
//and package the results and forward to JSP
if(topDocs!=null) {
ScoreDoc[] sd = topDocs.scoreDocs;
Document[] results=new Document[sd.length];
for (int i = 0; i < results.length; i++) {
results[i]=searcher.doc(sd[i].doc);
request.setAttribute("results", results);
}
}
RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/index.jsp");
dispatcher.forward(request,response);
}
catch(Exception e){
throw new ServletException("Error processing query",e);
}
}
private void openExampleIndex() throws CorruptIndexException, IOException {
//Create a RAM-based index from our test data file
RAMDirectory rd=new RAMDirectory();
IndexWriter writer=new IndexWriter (rd,analyzer,IndexWriter.MaxFieldLength.LIMITED);
InputStream dataIn=getServletContext().getResourceAsStream("/WEB-INF/data.tsv");
BufferedReader br = new BufferedReader(new InputStreamReader(dataIn));
String line = br.readLine();
while(line!=null)
{
line=line.trim();
if(line.length()>0)
{
//parse row and create a document
StringTokenizer st=new StringTokenizer(line,"\t");
Document doc=new Document();
doc.add(new Field("location",st.nextToken(),Field.Store.YES,
Field.Index.ANALYZED_NO_NORMS));
doc.add(new Field("salary",st.nextToken(),Field.Store.YES,
Field.Index.ANALYZED_NO_NORMS));
doc.add(new Field("type",st.nextToken(),Field.Store.YES,
Field.Index.ANALYZED_NO_NORMS));
doc.add(new Field("description",st.nextToken(),Field.Store.YES,
Field.Index.ANALYZED));
writer.addDocument(doc);
}
line=br.readLine();
}
writer.close();
//open searcher
searcher=new IndexSearcher(rd, true);
}
}