001 /*
002 * Licensed to the Apache Software Foundation (ASF) under one or more
003 * contributor license agreements. See the NOTICE file distributed with
004 * this work for additional information regarding copyright ownership.
005 * The ASF licenses this file to You under the Apache License, Version 2.0
006 * (the "License"); you may not use this file except in compliance with
007 * the License. You may obtain a copy of the License at
008 *
009 * http://www.apache.org/licenses/LICENSE-2.0
010 *
011 * Unless required by applicable law or agreed to in writing, software
012 * distributed under the License is distributed on an "AS IS" BASIS,
013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014 * See the License for the specific language governing permissions and
015 * limitations under the License.
016 */
017
018 package org.apache.lucene.demo.xmlparser;
019
020 import java.io.BufferedReader;
021 import java.io.IOException;
022 import java.io.InputStream;
023 import java.io.InputStreamReader;
024 import java.util.Enumeration;
025 import java.util.Properties;
026 import java.util.StringTokenizer;
027 import javax.servlet.RequestDispatcher;
028 import javax.servlet.ServletConfig;
029 import javax.servlet.ServletException;
030 import javax.servlet.http.HttpServlet;
031 import javax.servlet.http.HttpServletRequest;
032 import javax.servlet.http.HttpServletResponse;
033
034 import org.apache.lucene.analysis.Analyzer;
035 import org.apache.lucene.analysis.standard.StandardAnalyzer;
036 import org.apache.lucene.document.Document;
037 import org.apache.lucene.document.Field;
038 import org.apache.lucene.document.FieldType;
039 import org.apache.lucene.document.TextField;
040 import org.apache.lucene.index.CorruptIndexException;
041 import org.apache.lucene.index.DirectoryReader;
042 import org.apache.lucene.index.IndexReader;
043 import org.apache.lucene.index.IndexWriter;
044 import org.apache.lucene.index.IndexWriterConfig;
045 import org.apache.lucene.queryparser.xml.CorePlusExtensionsParser;
046 import org.apache.lucene.queryparser.xml.QueryTemplateManager;
047 import org.apache.lucene.search.IndexSearcher;
048 import org.apache.lucene.search.Query;
049 import org.apache.lucene.search.ScoreDoc;
050 import org.apache.lucene.search.TopDocs;
051 import org.apache.lucene.store.RAMDirectory;
052 import org.apache.lucene.util.Version;
053
054 /**
055 * Example servlet that uses the XML queryparser.
056 * <p>
057 * NOTE: you must provide CSV data in <code>/WEB-INF/data.tsv</code>
058 * for the demo to work!
059 */
060 public class FormBasedXmlQueryDemo extends HttpServlet {
061
062 private QueryTemplateManager queryTemplateManager;
063 private CorePlusExtensionsParser xmlParser;
064 private IndexSearcher searcher;
065 private Analyzer analyzer = new StandardAnalyzer(org.apache.lucene.util.Version.LUCENE_CURRENT);
066
067 @Override
068 public void init(ServletConfig config) throws ServletException {
069 super.init(config);
070 try {
071 openExampleIndex();
072
073 //load servlet configuration settings
074 String xslFile = config.getInitParameter("xslFile");
075 String defaultStandardQueryParserField = config.getInitParameter("defaultStandardQueryParserField");
076
077
078 //Load and cache choice of XSL query template using QueryTemplateManager
079 queryTemplateManager = new QueryTemplateManager(
080 getServletContext().getResourceAsStream("/WEB-INF/" + xslFile));
081
082 //initialize an XML Query Parser for use by all threads
083 xmlParser = new CorePlusExtensionsParser(defaultStandardQueryParserField, analyzer);
084 } catch (Exception e) {
085 throw new ServletException("Error loading query template", e);
086 }
087 }
088
089 @Override
090 protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
091 //Take all completed form fields and add to a Properties object
092 Properties completedFormFields = new Properties();
093 Enumeration<?> pNames = request.getParameterNames();
094 while (pNames.hasMoreElements()) {
095 String propName = (String) pNames.nextElement();
096 String value = request.getParameter(propName);
097 if ((value != null) && (value.trim().length() > 0)) {
098 completedFormFields.setProperty(propName, value);
099 }
100 }
101
102 try {
103 //Create an XML query by populating template with given user criteria
104 org.w3c.dom.Document xmlQuery = queryTemplateManager.getQueryAsDOM(completedFormFields);
105
106 //Parse the XML to produce a Lucene query
107 Query query = xmlParser.getQuery(xmlQuery.getDocumentElement());
108
109 //Run the query
110 TopDocs topDocs = searcher.search(query, 10);
111
112 //and package the results and forward to JSP
113 if (topDocs != null) {
114 ScoreDoc[] sd = topDocs.scoreDocs;
115 Document[] results = new Document[sd.length];
116 for (int i = 0; i < results.length; i++) {
117 results[i] = searcher.doc(sd[i].doc);
118 request.setAttribute("results", results);
119 }
120 }
121 RequestDispatcher dispatcher = getServletContext().getRequestDispatcher("/index.jsp");
122 dispatcher.forward(request, response);
123 }
124 catch (Exception e) {
125 throw new ServletException("Error processing query", e);
126 }
127 }
128
129 private void openExampleIndex() throws CorruptIndexException, IOException {
130 //Create a RAM-based index from our test data file
131 RAMDirectory rd = new RAMDirectory();
132 IndexWriterConfig iwConfig = new IndexWriterConfig(Version.LUCENE_40, analyzer);
133 IndexWriter writer = new IndexWriter(rd, iwConfig);
134 InputStream dataIn = getServletContext().getResourceAsStream("/WEB-INF/data.tsv");
135 BufferedReader br = new BufferedReader(new InputStreamReader(dataIn));
136 String line = br.readLine();
137 final FieldType textNoNorms = new FieldType(TextField.TYPE_STORED);
138 textNoNorms.setOmitNorms(true);
139 while (line != null) {
140 line = line.trim();
141 if (line.length() > 0) {
142 //parse row and create a document
143 StringTokenizer st = new StringTokenizer(line, "\t");
144 Document doc = new Document();
145 doc.add(new Field("location", st.nextToken(), textNoNorms));
146 doc.add(new Field("salary", st.nextToken(), textNoNorms));
147 doc.add(new Field("type", st.nextToken(), textNoNorms));
148 doc.add(new Field("description", st.nextToken(), textNoNorms));
149 writer.addDocument(doc);
150 }
151 line = br.readLine();
152 }
153 writer.close();
154
155 //open searcher
156 // this example never closes it reader!
157 IndexReader reader = DirectoryReader.open(rd);
158 searcher = new IndexSearcher(reader);
159 }
160 }