| /* |
| * @(#)$Id$ |
| * |
| * The Apache Software License, Version 1.1 |
| * |
| * |
| * Copyright (c) 2001 The Apache Software Foundation. All rights |
| * reserved. |
| * |
| * Redistribution and use in source and binary forms, with or without |
| * modification, are permitted provided that the following conditions |
| * are met: |
| * |
| * 1. Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * |
| * 2. Redistributions in binary form must reproduce the above copyright |
| * notice, this list of conditions and the following disclaimer in |
| * the documentation and/or other materials provided with the |
| * distribution. |
| * |
| * 3. The end-user documentation included with the redistribution, |
| * if any, must include the following acknowledgment: |
| * "This product includes software developed by the |
| * Apache Software Foundation (http://www.apache.org/)." |
| * Alternately, this acknowledgment may appear in the software itself, |
| * if and wherever such third-party acknowledgments normally appear. |
| * |
| * 4. The names "Xalan" and "Apache Software Foundation" must |
| * not be used to endorse or promote products derived from this |
| * software without prior written permission. For written |
| * permission, please contact apache@apache.org. |
| * |
| * 5. Products derived from this software may not be called "Apache", |
| * nor may "Apache" appear in their name, without prior written |
| * permission of the Apache Software Foundation. |
| * |
| * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED |
| * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
| * DISCLAIMED. IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR |
| * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF |
| * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
| * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, |
| * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT |
| * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| * SUCH DAMAGE. |
| * ==================================================================== |
| * |
| * This software consists of voluntary contributions made by many |
| * individuals on behalf of the Apache Software Foundation and was |
| * originally based on software copyright (c) 2001, Sun |
| * Microsystems., http://www.sun.com. For more |
| * information on the Apache Software Foundation, please see |
| * <http://www.apache.org/>. |
| * |
| * @author Morten Jorgensen |
| * |
| */ |
| |
| package org.apache.xalan.xsltc.dom; |
| |
| import java.io.PrintWriter; |
| import java.io.File; |
| import java.io.IOException; |
| import java.net.URL; |
| import java.net.URLDecoder; |
| import java.net.URLConnection; |
| import java.net.MalformedURLException; |
| import java.util.Hashtable; |
| import java.util.Date; |
| |
| import javax.xml.parsers.SAXParser; |
| import javax.xml.parsers.SAXParserFactory; |
| import javax.xml.parsers.ParserConfigurationException; |
| |
| import org.xml.sax.XMLReader; |
| import org.xml.sax.SAXException; |
| |
| import org.apache.xalan.xsltc.DOM; |
| import org.apache.xalan.xsltc.DOMCache; |
| import org.apache.xalan.xsltc.Translet; |
| import org.apache.xalan.xsltc.dom.DOMImpl; |
| import org.apache.xalan.xsltc.dom.DTDMonitor; |
| import org.apache.xalan.xsltc.runtime.AbstractTranslet; |
| import org.apache.xalan.xsltc.runtime.Constants; |
| |
| public final class DocumentCache implements DOMCache { |
| |
| private int _size; |
| private Hashtable _references; |
| private String[] _URIs; |
| private int _count; |
| private int _current; |
| private SAXParser _parser; |
| private XMLReader _reader; |
| |
| private static final int REFRESH_INTERVAL = 1000; |
| |
| /* |
| * Inner class containing a DOMImpl object and DTD handler |
| */ |
| public final class CachedDocument { |
| |
| // Statistics data |
| private long _firstReferenced; |
| private long _lastReferenced; |
| private long _accessCount; |
| private long _lastModified; |
| private long _lastChecked; |
| private long _buildTime; |
| |
| // DOM and DTD handler references |
| private DOMImpl _dom = null; |
| private DTDMonitor _dtdMonitor = null; |
| |
| /** |
| * Constructor - load document and initialise statistics |
| */ |
| public CachedDocument(String uri) { |
| // Initialise statistics variables |
| final long stamp = System.currentTimeMillis(); |
| _firstReferenced = stamp; |
| _lastReferenced = stamp; |
| _accessCount = 0; |
| loadDocument(uri); |
| |
| _buildTime = System.currentTimeMillis() - stamp; |
| } |
| |
| /** |
| * Loads the document and updates build-time (latency) statistics |
| */ |
| public void loadDocument(String uri) { |
| |
| _dom = new DOMImpl(); |
| _dtdMonitor = new DTDMonitor(); |
| |
| try { |
| final long stamp = System.currentTimeMillis(); |
| |
| _reader.setContentHandler(_dom.getBuilder()); |
| _dtdMonitor.handleDTD(_reader); |
| _reader.parse(uri); |
| _dom.setDocumentURI(uri); |
| |
| // The build time can be used for statistics for a better |
| // priority algorithm (currently round robin). |
| final long thisTime = System.currentTimeMillis() - stamp; |
| if (_buildTime > 0) |
| _buildTime = (_buildTime + thisTime) >>> 1; |
| else |
| _buildTime = thisTime; |
| } |
| catch (Exception e) { |
| _dom = null; |
| _dtdMonitor = null; |
| } |
| } |
| |
| public DOMImpl getDocument() { return(_dom); } |
| |
| public DTDMonitor getDTDMonitor() { return(_dtdMonitor); } |
| |
| public long getFirstReferenced() { return(_firstReferenced); } |
| |
| public long getLastReferenced() { return(_lastReferenced); } |
| |
| public long getAccessCount() { return(_accessCount); } |
| |
| public void incAccessCount() { _accessCount++; } |
| |
| public long getLastModified() { return(_lastModified); } |
| |
| public void setLastModified(long t){ _lastModified = t; } |
| |
| public long getLatency() { return(_buildTime); } |
| |
| public long getLastChecked() { return(_lastChecked); } |
| |
| public void setLastChecked(long t) { _lastChecked = t; } |
| |
| public long getEstimatedSize() { |
| if (_dom != null) |
| return(_dom.getSize() << 5); // ??? |
| else |
| return(0); |
| } |
| |
| } |
| |
| /** |
| * DocumentCache constructor |
| */ |
| public DocumentCache(int size) throws SAXException { |
| _count = 0; |
| _current = 0; |
| _size = size; |
| _references = new Hashtable(_size+2); |
| _URIs = new String[_size]; |
| |
| try { |
| // Create a SAX parser and get the XMLReader object it uses |
| final SAXParserFactory factory = SAXParserFactory.newInstance(); |
| try { |
| factory.setFeature(Constants.NAMESPACE_FEATURE,true); |
| } |
| catch (Exception e) { |
| factory.setNamespaceAware(true); |
| } |
| _parser = factory.newSAXParser(); |
| _reader = _parser.getXMLReader(); |
| } |
| catch (ParserConfigurationException e) { |
| System.err.println("Your SAX parser is not configured correctly."); |
| System.exit(-1); |
| } |
| } |
| |
| /** |
| * Returns the time-stamp for a document's last update |
| */ |
| private final long getLastModified(String uri) { |
| try { |
| URL url = new URL(uri); |
| URLConnection connection = url.openConnection(); |
| long timestamp = connection.getLastModified(); |
| // Check for a "file:" URI (courtesy of Brian Ewins) |
| if (timestamp == 0){ // get 0 for local URI |
| if ("file".equals(url.getProtocol())){ |
| File localfile = new File(URLDecoder.decode(url.getFile())); |
| timestamp = localfile.lastModified(); |
| } |
| } |
| return(timestamp); |
| } |
| // Brutal handling of all exceptions |
| catch (Exception e) { |
| return(System.currentTimeMillis()); |
| } |
| } |
| |
| /** |
| * |
| */ |
| private CachedDocument lookupDocument(String uri) { |
| return((CachedDocument)_references.get(uri)); |
| } |
| |
| /** |
| * |
| */ |
| private synchronized void insertDocument(String uri, CachedDocument doc) { |
| if (_count < _size) { |
| // Insert out URI in circular buffer |
| _URIs[_count++] = uri; |
| _current = 0; |
| } |
| else { |
| // Remove oldest URI from reference Hashtable |
| _references.remove(_URIs[_current]); |
| // Insert our URI in circular buffer |
| _URIs[_current] = uri; |
| if (++_current >= _size) _current = 0; |
| } |
| _references.put(uri, doc); |
| } |
| |
| /** |
| * |
| */ |
| private synchronized void replaceDocument(String uri, CachedDocument doc) { |
| CachedDocument old = (CachedDocument)_references.get(uri); |
| if (doc == null) |
| insertDocument(uri, doc); |
| else |
| _references.put(uri, doc); |
| } |
| |
| /** |
| * Returns a document either by finding it in the cache or |
| * downloading it and putting it in the cache. |
| */ |
| public final DOMImpl retrieveDocument(String uri, int mask, Translet trs) { |
| CachedDocument doc; |
| |
| // Try to get the document from the cache first |
| if ((doc = lookupDocument(uri)) == null) { |
| doc = new CachedDocument(uri); |
| if (doc == null) return null; // better error handling needed!!! |
| doc.setLastModified(getLastModified(uri)); |
| insertDocument(uri, doc); |
| } |
| // If the document is in the cache we must check if it is still valid |
| else { |
| long now = System.currentTimeMillis(); |
| long chk = doc.getLastChecked(); |
| doc.setLastChecked(now); |
| // Has the modification time for this file been checked lately? |
| if (now > (chk + REFRESH_INTERVAL)) { |
| doc.setLastChecked(now); |
| long last = getLastModified(uri); |
| // Reload document if it has been modified since last download |
| if (last > doc.getLastModified()) { |
| doc = new CachedDocument(uri); |
| if (doc == null) return null; |
| doc.setLastModified(getLastModified(uri)); |
| replaceDocument(uri, doc); |
| } |
| } |
| |
| } |
| |
| // Get the references to the actual DOM and DTD handler |
| final DOMImpl dom = doc.getDocument(); |
| final DTDMonitor dtd = doc.getDTDMonitor(); |
| |
| // The dom reference may be null if the URL pointed to a |
| // non-existing document |
| if (dom == null) return null; |
| |
| doc.incAccessCount(); // For statistics |
| |
| final AbstractTranslet translet = (AbstractTranslet)trs; |
| |
| // Set minimum needed size for key/id indices in the translet |
| translet.setIndexSize(dom.getSize()); |
| // Create index for any ID attributes defined in the document DTD |
| dtd.buildIdIndex(dom, mask, translet); |
| // Pass all unparsed entities to the translet |
| translet.setUnparsedEntityURIs(dtd.getUnparsedEntityURIs()); |
| |
| return(doc.getDocument()); |
| } |
| |
| /** |
| * Outputs the cache statistics |
| */ |
| public void getStatistics(PrintWriter out) { |
| out.println("<h2>DOM cache statistics</h2><center><table border=\"2\">"+ |
| "<tr><td><b>Document URI</b></td>"+ |
| "<td><center><b>Build time</b></center></td>"+ |
| "<td><center><b>Access count</b></center></td>"+ |
| "<td><center><b>Last accessed</b></center></td>"+ |
| "<td><center><b>Last modified</b></center></td></tr>"); |
| |
| for (int i=0; i<_count; i++) { |
| CachedDocument doc = (CachedDocument)_references.get(_URIs[i]); |
| out.print("<tr><td><a href=\""+_URIs[i]+"\">"+ |
| "<font size=-1>"+_URIs[i]+"</font></a></td>"); |
| out.print("<td><center>"+doc.getLatency()+"ms</center></td>"); |
| out.print("<td><center>"+doc.getAccessCount()+"</center></td>"); |
| out.print("<td><center>"+(new Date(doc.getLastReferenced()))+ |
| "</center></td>"); |
| out.print("<td><center>"+(new Date(doc.getLastModified()))+ |
| "</center></td>"); |
| out.println("</tr>"); |
| } |
| |
| out.println("</table></center>"); |
| } |
| } |