1 /* 2 * Copyright (c) 2015, 2017, Oracle and/or its affiliates. All rights reserved. 3 */ 4 /* 5 * Licensed to the Apache Software Foundation (ASF) under one or more 6 * contributor license agreements. See the NOTICE file distributed with 7 * this work for additional information regarding copyright ownership. 8 * The ASF licenses this file to You under the Apache License, Version 2.0 9 * (the "License"); you may not use this file except in compliance with 10 * the License. You may obtain a copy of the License at 11 * 12 * http://www.apache.org/licenses/LICENSE-2.0 13 * 14 * Unless required by applicable law or agreed to in writing, software 15 * distributed under the License is distributed on an "AS IS" BASIS, 16 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 17 * See the License for the specific language governing permissions and 18 * limitations under the License. 19 */ 20 /* 21 * $Id: DocumentCache.java,v 1.2.4.1 2005/09/06 06:15:22 pvedula Exp $ 22 */ 23 24 package com.sun.org.apache.xalan.internal.xsltc.dom; 25 26 import com.sun.org.apache.xalan.internal.xsltc.DOM; 27 import com.sun.org.apache.xalan.internal.xsltc.DOMCache; 28 import com.sun.org.apache.xalan.internal.xsltc.DOMEnhancedForDTM; 29 import com.sun.org.apache.xalan.internal.xsltc.Translet; 30 import com.sun.org.apache.xalan.internal.xsltc.runtime.AbstractTranslet; 31 import com.sun.org.apache.xalan.internal.xsltc.runtime.BasisLibrary; 32 import com.sun.org.apache.xalan.internal.xsltc.runtime.Constants; 33 import com.sun.org.apache.xml.internal.utils.SystemIDResolver; 34 import java.io.File; 35 import java.io.PrintWriter; 36 import java.net.URL; 37 import java.net.URLConnection; 38 import java.nio.file.Paths; 39 import java.util.Date; 40 import java.util.HashMap; 41 import java.util.Map; 42 import javax.xml.parsers.ParserConfigurationException; 43 import javax.xml.parsers.SAXParser; 44 import javax.xml.parsers.SAXParserFactory; 45 import javax.xml.transform.TransformerException; 46 import javax.xml.transform.sax.SAXSource; 47 import org.xml.sax.InputSource; 48 import org.xml.sax.SAXException; 49 import org.xml.sax.XMLReader; 50 51 /** 52 * @author Morten Jorgensen 53 */ 54 public final class DocumentCache implements DOMCache { 55 56 private int _size; 57 private Map<String, CachedDocument> _references; 58 private String[] _URIs; 59 private int _count; 60 private int _current; 61 private SAXParser _parser; 62 private XMLReader _reader; 63 private XSLTCDTMManager _dtmManager; 64 65 private static final int REFRESH_INTERVAL = 1000; 66 67 /* 68 * Inner class containing a DOMImpl object and DTD handler 69 */ 70 public final class CachedDocument { 71 72 // Statistics data 73 private long _firstReferenced; 74 private long _lastReferenced; 75 private long _accessCount; 76 private long _lastModified; 77 private long _lastChecked; 78 private long _buildTime; 79 80 // DOM and DTD handler references 81 private DOMEnhancedForDTM _dom = null; 82 83 /** 84 * Constructor - load document and initialise statistics 85 */ CachedDocument(String uri)86 public CachedDocument(String uri) { 87 // Initialise statistics variables 88 final long stamp = System.currentTimeMillis(); 89 _firstReferenced = stamp; 90 _lastReferenced = stamp; 91 _accessCount = 0; 92 loadDocument(uri); 93 94 _buildTime = System.currentTimeMillis() - stamp; 95 } 96 97 /** 98 * Loads the document and updates build-time (latency) statistics 99 */ loadDocument(String uri)100 public void loadDocument(String uri) { 101 102 try { 103 final long stamp = System.currentTimeMillis(); 104 _dom = (DOMEnhancedForDTM)_dtmManager.getDTM( 105 new SAXSource(_reader, new InputSource(uri)), 106 false, null, true, false); 107 _dom.setDocumentURI(uri); 108 109 // The build time can be used for statistics for a better 110 // priority algorithm (currently round robin). 111 final long thisTime = System.currentTimeMillis() - stamp; 112 if (_buildTime > 0) 113 _buildTime = (_buildTime + thisTime) >>> 1; 114 else 115 _buildTime = thisTime; 116 } 117 catch (Exception e) { 118 _dom = null; 119 } 120 } 121 getDocument()122 public DOM getDocument() { return(_dom); } 123 getFirstReferenced()124 public long getFirstReferenced() { return(_firstReferenced); } 125 getLastReferenced()126 public long getLastReferenced() { return(_lastReferenced); } 127 getAccessCount()128 public long getAccessCount() { return(_accessCount); } 129 incAccessCount()130 public void incAccessCount() { _accessCount++; } 131 getLastModified()132 public long getLastModified() { return(_lastModified); } 133 setLastModified(long t)134 public void setLastModified(long t){ _lastModified = t; } 135 getLatency()136 public long getLatency() { return(_buildTime); } 137 getLastChecked()138 public long getLastChecked() { return(_lastChecked); } 139 setLastChecked(long t)140 public void setLastChecked(long t) { _lastChecked = t; } 141 getEstimatedSize()142 public long getEstimatedSize() { 143 if (_dom != null) 144 return(_dom.getSize() << 5); // ??? 145 else 146 return(0); 147 } 148 149 } 150 151 /** 152 * DocumentCache constructor 153 */ DocumentCache(int size)154 public DocumentCache(int size) throws SAXException { 155 this(size, null); 156 try { 157 _dtmManager = XSLTCDTMManager.createNewDTMManagerInstance(); 158 } catch (Exception e) { 159 throw new SAXException(e); 160 } 161 } 162 163 /** 164 * DocumentCache constructor 165 */ DocumentCache(int size, XSLTCDTMManager dtmManager)166 public DocumentCache(int size, XSLTCDTMManager dtmManager) throws SAXException { 167 _dtmManager = dtmManager; 168 _count = 0; 169 _current = 0; 170 _size = size; 171 _references = new HashMap<>(_size+2); 172 _URIs = new String[_size]; 173 174 try { 175 // Create a SAX parser and get the XMLReader object it uses 176 final SAXParserFactory factory = SAXParserFactory.newInstance(); 177 try { 178 factory.setFeature(Constants.NAMESPACE_FEATURE,true); 179 } 180 catch (Exception e) { 181 factory.setNamespaceAware(true); 182 } 183 _parser = factory.newSAXParser(); 184 _reader = _parser.getXMLReader(); 185 } 186 catch (ParserConfigurationException e) { 187 BasisLibrary.runTimeError(BasisLibrary.NAMESPACES_SUPPORT_ERR); 188 } 189 } 190 191 /** 192 * Returns the time-stamp for a document's last update 193 */ getLastModified(String uri)194 private final long getLastModified(String uri) { 195 try { 196 URL url = new URL(uri); 197 URLConnection connection = url.openConnection(); 198 long timestamp = connection.getLastModified(); 199 // Check for a "file:" URI (courtesy of Brian Ewins) 200 if (timestamp == 0){ // get 0 for local URI 201 if ("file".equals(url.getProtocol())){ 202 File localfile = Paths.get(url.toURI()).toFile(); 203 timestamp = localfile.lastModified(); 204 } 205 } 206 return(timestamp); 207 } 208 // Brutal handling of all exceptions 209 catch (Exception e) { 210 return(System.currentTimeMillis()); 211 } 212 } 213 214 /** 215 * 216 */ lookupDocument(String uri)217 private CachedDocument lookupDocument(String uri) { 218 return(_references.get(uri)); 219 } 220 221 /** 222 * 223 */ insertDocument(String uri, CachedDocument doc)224 private synchronized void insertDocument(String uri, CachedDocument doc) { 225 if (_count < _size) { 226 // Insert out URI in circular buffer 227 _URIs[_count++] = uri; 228 _current = 0; 229 } 230 else { 231 // Remove oldest URI from reference map 232 _references.remove(_URIs[_current]); 233 // Insert our URI in circular buffer 234 _URIs[_current] = uri; 235 if (++_current >= _size) _current = 0; 236 } 237 _references.put(uri, doc); 238 } 239 240 /** 241 * 242 */ replaceDocument(String uri, CachedDocument doc)243 private synchronized void replaceDocument(String uri, CachedDocument doc) { 244 if (doc == null) 245 insertDocument(uri, doc); 246 else 247 _references.put(uri, doc); 248 } 249 250 /** 251 * Returns a document either by finding it in the cache or 252 * downloading it and putting it in the cache. 253 */ 254 @Override retrieveDocument(String baseURI, String href, Translet trs)255 public DOM retrieveDocument(String baseURI, String href, Translet trs) { 256 CachedDocument doc; 257 258 String uri = href; 259 if (baseURI != null && !baseURI.equals("")) { 260 try { 261 uri = SystemIDResolver.getAbsoluteURI(uri, baseURI); 262 } catch (TransformerException te) { 263 // ignore 264 } 265 } 266 267 // Try to get the document from the cache first 268 if ((doc = lookupDocument(uri)) == null) { 269 doc = new CachedDocument(uri); 270 if (doc == null) return null; // better error handling needed!!! 271 doc.setLastModified(getLastModified(uri)); 272 insertDocument(uri, doc); 273 } 274 // If the document is in the cache we must check if it is still valid 275 else { 276 long now = System.currentTimeMillis(); 277 long chk = doc.getLastChecked(); 278 doc.setLastChecked(now); 279 // Has the modification time for this file been checked lately? 280 if (now > (chk + REFRESH_INTERVAL)) { 281 doc.setLastChecked(now); 282 long last = getLastModified(uri); 283 // Reload document if it has been modified since last download 284 if (last > doc.getLastModified()) { 285 doc = new CachedDocument(uri); 286 if (doc == null) return null; 287 doc.setLastModified(getLastModified(uri)); 288 replaceDocument(uri, doc); 289 } 290 } 291 292 } 293 294 // Get the references to the actual DOM and DTD handler 295 final DOM dom = doc.getDocument(); 296 297 // The dom reference may be null if the URL pointed to a 298 // non-existing document 299 if (dom == null) return null; 300 301 doc.incAccessCount(); // For statistics 302 303 final AbstractTranslet translet = (AbstractTranslet)trs; 304 305 // Give the translet an early opportunity to extract any 306 // information from the DOM object that it would like. 307 translet.prepassDocument(dom); 308 309 return(doc.getDocument()); 310 } 311 312 /** 313 * Outputs the cache statistics 314 */ getStatistics(PrintWriter out)315 public void getStatistics(PrintWriter out) { 316 out.println("<h2>DOM cache statistics</h2><center><table border=\"2\">"+ 317 "<tr><td><b>Document URI</b></td>"+ 318 "<td><center><b>Build time</b></center></td>"+ 319 "<td><center><b>Access count</b></center></td>"+ 320 "<td><center><b>Last accessed</b></center></td>"+ 321 "<td><center><b>Last modified</b></center></td></tr>"); 322 323 for (int i=0; i<_count; i++) { 324 CachedDocument doc = _references.get(_URIs[i]); 325 out.print("<tr><td><a href=\""+_URIs[i]+"\">"+ 326 "<font size=-1>"+_URIs[i]+"</font></a></td>"); 327 out.print("<td><center>"+doc.getLatency()+"ms</center></td>"); 328 out.print("<td><center>"+doc.getAccessCount()+"</center></td>"); 329 out.print("<td><center>"+(new Date(doc.getLastReferenced()))+ 330 "</center></td>"); 331 out.print("<td><center>"+(new Date(doc.getLastModified()))+ 332 "</center></td>"); 333 out.println("</tr>"); 334 } 335 336 out.println("</table></center>"); 337 } 338 } 339