1 package org.apache.lucene.xmlparser;
2
3 import java.io.ByteArrayOutputStream;
4 import java.io.IOException;
5 import java.io.InputStream;
6 import java.util.Enumeration;
7 import java.util.HashMap;
8 import java.util.Properties;
9
10 import javax.xml.parsers.DocumentBuilder;
11 import javax.xml.parsers.DocumentBuilderFactory;
12 import javax.xml.parsers.ParserConfigurationException;
13 import javax.xml.transform.Result;
14 import javax.xml.transform.Source;
15 import javax.xml.transform.Templates;
16 import javax.xml.transform.Transformer;
17 import javax.xml.transform.TransformerConfigurationException;
18 import javax.xml.transform.TransformerException;
19 import javax.xml.transform.TransformerFactory;
20 import javax.xml.transform.dom.DOMResult;
21 import javax.xml.transform.dom.DOMSource;
22 import javax.xml.transform.stream.StreamResult;
23
24 import org.w3c.dom.Document;
25 import org.w3c.dom.Element;
26 import org.xml.sax.SAXException;
27
28 /**
29 * Licensed to the Apache Software Foundation (ASF) under one or more
30 * contributor license agreements. See the NOTICE file distributed with
31 * this work for additional information regarding copyright ownership.
32 * The ASF licenses this file to You under the Apache License, Version 2.0
33 * (the "License"); you may not use this file except in compliance with
34 * the License. You may obtain a copy of the License at
35 *
36 * http://www.apache.org/licenses/LICENSE-2.0
37 *
38 * Unless required by applicable law or agreed to in writing, software
39 * distributed under the License is distributed on an "AS IS" BASIS,
40 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
41 * See the License for the specific language governing permissions and
42 * limitations under the License.
43 */
44 /**
45 * Provides utilities for turning query form input (such as from a web page or Swing gui) into
46 * Lucene XML queries by using XSL templates. This approach offers a convenient way of externalizing
47 * and changing how user input is turned into Lucene queries.
48 * Database applications often adopt similar practices by externalizing SQL in template files that can
49 * be easily changed/optimized by a DBA.
50 * The static methods can be used on their own or by creating an instance of this class you can store and
51 * re-use compiled stylesheets for fast use (e.g. in a server environment)
52 */
53 public class QueryTemplateManager
54 {
55 static DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance ();
56 static TransformerFactory tFactory = TransformerFactory.newInstance();
57
58 HashMap<String,Templates> compiledTemplatesCache=new HashMap<String,Templates>();
59 Templates defaultCompiledTemplates=null;
60
61
62 public QueryTemplateManager()
63 {
64
65 }
66 public QueryTemplateManager(InputStream xslIs) throws TransformerConfigurationException, ParserConfigurationException, SAXException, IOException
67 {
68 addDefaultQueryTemplate(xslIs);
69 }
70 public void addDefaultQueryTemplate(InputStream xslIs) throws TransformerConfigurationException, ParserConfigurationException, SAXException, IOException
71 {
72 defaultCompiledTemplates=getTemplates(xslIs);
73 }
74 public void addQueryTemplate(String name, InputStream xslIs) throws TransformerConfigurationException, ParserConfigurationException, SAXException, IOException
75 {
76 compiledTemplatesCache.put(name,getTemplates(xslIs));
77 }
78 public String getQueryAsXmlString(Properties formProperties,String queryTemplateName) throws SAXException, IOException, ParserConfigurationException, TransformerException
79 {
80 Templates ts= compiledTemplatesCache.get(queryTemplateName);
81 return getQueryAsXmlString(formProperties, ts);
82 }
83
84 public Document getQueryAsDOM(Properties formProperties,String queryTemplateName) throws SAXException, IOException, ParserConfigurationException, TransformerException
85 {
86 Templates ts= compiledTemplatesCache.get(queryTemplateName);
87 return getQueryAsDOM(formProperties, ts);
88 }
89 public String getQueryAsXmlString(Properties formProperties) throws SAXException, IOException, ParserConfigurationException, TransformerException
90 {
91 return getQueryAsXmlString(formProperties, defaultCompiledTemplates);
92 }
93
94 public Document getQueryAsDOM(Properties formProperties) throws SAXException, IOException, ParserConfigurationException, TransformerException
95 {
96 return getQueryAsDOM(formProperties, defaultCompiledTemplates);
97 }
98
99
100 /**
101 * Fast means of constructing query using a precompiled stylesheet
102 */
103 public static String getQueryAsXmlString(Properties formProperties, Templates template) throws SAXException, IOException, ParserConfigurationException, TransformerException
104 {
105 ByteArrayOutputStream baos=new ByteArrayOutputStream();
106 StreamResult result=new StreamResult(baos);
107 transformCriteria(formProperties,template,result);
108 return baos.toString();
109 }
110
111 /**
112 * Slow means of constructing query parsing a stylesheet from an input stream
113 */
114 public static String getQueryAsXmlString(Properties formProperties, InputStream xslIs) throws SAXException, IOException, ParserConfigurationException, TransformerException
115 {
116 ByteArrayOutputStream baos=new ByteArrayOutputStream();
117 StreamResult result=new StreamResult(baos);
118 transformCriteria(formProperties,xslIs,result);
119 return baos.toString();
120 }
121
122
123 /**
124 * Fast means of constructing query using a cached,precompiled stylesheet
125 */
126 public static Document getQueryAsDOM(Properties formProperties, Templates template) throws SAXException, IOException, ParserConfigurationException, TransformerException
127 {
128 DOMResult result=new DOMResult();
129 transformCriteria(formProperties,template,result);
130 return (Document)result.getNode();
131 }
132
133
134 /**
135 * Slow means of constructing query - parses stylesheet from input stream
136 */
137 public static Document getQueryAsDOM(Properties formProperties, InputStream xslIs) throws SAXException, IOException, ParserConfigurationException, TransformerException
138 {
139 DOMResult result=new DOMResult();
140 transformCriteria(formProperties,xslIs,result);
141 return (Document)result.getNode();
142 }
143
144
145
146
147 /**
148 * Slower transformation using an uncompiled stylesheet (suitable for development environment)
149 */
150 public static void transformCriteria(Properties formProperties, InputStream xslIs, Result result) throws SAXException, IOException, ParserConfigurationException, TransformerException
151 {
152 dbf.setNamespaceAware(true);
153 DocumentBuilder builder = dbf.newDocumentBuilder();
154 org.w3c.dom.Document xslDoc = builder.parse(xslIs);
155 DOMSource ds = new DOMSource(xslDoc);
156
157 Transformer transformer =null;
158 synchronized (tFactory)
159 {
160 transformer = tFactory.newTransformer(ds);
161 }
162 transformCriteria(formProperties,transformer,result);
163 }
164
165 /**
166 * Fast transformation using a pre-compiled stylesheet (suitable for production environments)
167 */
168 public static void transformCriteria(Properties formProperties, Templates template, Result result) throws SAXException, IOException, ParserConfigurationException, TransformerException
169 {
170 transformCriteria(formProperties,template.newTransformer(),result);
171 }
172
173
174
175 public static void transformCriteria(Properties formProperties, Transformer transformer, Result result) throws SAXException, IOException, ParserConfigurationException, TransformerException
176 {
177 dbf.setNamespaceAware(true);
178
179 //Create an XML document representing the search index document.
180 DocumentBuilder db = dbf.newDocumentBuilder ();
181 org.w3c.dom.Document doc = db.newDocument ();
182 Element root = doc.createElement ("Document");
183 doc.appendChild (root);
184
185 Enumeration keysEnum = formProperties.keys();
186 while(keysEnum.hasMoreElements())
187 {
188 String propName=(String) keysEnum.nextElement();
189 String value=formProperties.getProperty(propName);
190 if((value!=null)&&(value.length()>0))
191 {
192 DOMUtils.insertChild(root,propName,value);
193 }
194 }
195 //Use XSLT to to transform into an XML query string using the queryTemplate
196 DOMSource xml=new DOMSource(doc);
197 transformer.transform(xml,result);
198 }
199
200 /**
201 * Parses a query stylesheet for repeated use
202 */
203 public static Templates getTemplates(InputStream xslIs) throws ParserConfigurationException, SAXException, IOException, TransformerConfigurationException
204 {
205 dbf.setNamespaceAware(true);
206 DocumentBuilder builder = dbf.newDocumentBuilder();
207 org.w3c.dom.Document xslDoc = builder.parse(xslIs);
208 DOMSource ds = new DOMSource(xslDoc);
209 return tFactory.newTemplates(ds);
210 }
211 }