Java tutorial
/* * 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.cocoon.generation; import java.io.BufferedReader; import java.io.File; import java.io.IOException; import java.io.InputStreamReader; import java.util.HashMap; import java.util.Map; import org.apache.avalon.framework.parameters.Parameters; import org.apache.avalon.framework.service.ServiceException; import org.apache.avalon.framework.service.ServiceManager; import org.apache.commons.logging.Log; import org.apache.excalibur.source.Source; import org.apache.excalibur.source.SourceNotFoundException; import org.apache.excalibur.xml.xpath.PrefixResolver; import org.apache.excalibur.xml.xpath.XPathProcessor; import org.apache.regexp.RE; import org.apache.regexp.RESyntaxException; import org.apache.cocoon.ProcessingException; import org.apache.cocoon.components.source.util.SourceUtil; import org.apache.cocoon.core.xml.DOMParser; import org.apache.cocoon.environment.SourceResolver; import org.apache.cocoon.xml.dom.DOMStreamer; import org.w3c.dom.Document; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; import org.xml.sax.helpers.AttributesImpl; /** * Generates an XML directory listing performing XPath queries on XML files. It * can be used both as a plain DirectoryGenerator or, by specifying a parameter * <code>xpath</code>, it will perform an XPath query on every XML resource. * <p> * Generates an XML directory listing performing XPath queries on XML files. It can be used both as a plain * DirectoryGenerator or, by specifying a parameter <code>xpath</code>, it will perform an XPath query on every XML * resource. A <code>nsmapping</code> parameter can be specified to point to a file containing lines to map prefixes * to namespaces like this: * </p> * * <p> * prefix=namespace-uri<br/> prefix2=namespace-uri-2 * </p> * * <p> * A parameter <code>nsmapping-reload</code> specifies if the prefix-2-namespace mapping file should be checked to be * reloaded on each request to this generator if it was modified since the last time it was read. * </p> * * <p> * An additional parameter <code>xmlFiles</code> can be set in the sitemap setting the regular expression pattern for * determining if a file should be handled as XML file or not. The default value for this param is * <code>\.xml$</code>, so that it matches all files ending <code>.xml</code>. * </p> * * <p></p> * <br>Sample usage: <br><br>Sitemap: * <pre> * <map:match pattern="documents/**"> * <map:generate type="xpathdirectory" src="docs/{1}"> * <map:parameter name="xpath" value="/article/title|/article/abstract"/> * <map:parameter name="nsmapping" value="mapping.properties"/> * <map:parameter name="nsmapping-reload" value="false"/> * <map:parameter name="xmlFiles" value="\.xml$"/> * </map:generate> * <map:serialize type="xml" /> * </map:match> * </pre> * * <p> * Request: <br>http://www.some.host/documents/test * </p> * Result: * <pre> * <dir:directory name="test" lastModified="1010400942000" date="1/7/02 11:55 AM" requested="true" xmlns:dir="http://apache.org/cocoon/directory/2.0"> * <dir:directory name="subdirectory" lastModified="1010400942000" date="1/7/02 11:55 AM"/> * <dir:file name="test.xml" lastModified="1011011579000" date="1/14/02 1:32 PM"> * <dir:xpath query="/article/title"> * <title>This is a test document</title> * <abstract> * <para>Abstract of my test article</para> * </abstract> * </dir:xpath> * </dir:file> * <dir:file name="test.gif" lastModified="1011011579000" date="1/14/02 1:32 PM"/> * </dir:directory> * </pre> * * @cocoon.sitemap.component.documentation * Generates an XML directory listing performing XPath queries on XML files. It * can be used both as a plain DirectoryGenerator or, by specifying a parameter * <code>xpath</code>, it will perform an XPath query on every XML resource. * @cocoon.sitemap.component.name xpathdirectory * @cocoon.sitemap.component.label content * @cocoon.sitemap.component.documentation.caching Yes. * Uses the last modification date of the directory and the contained documents * * @version $Id: XPathDirectoryGenerator.java 605605 2007-12-19 16:19:51Z vgritsenko $ */ public class XPathDirectoryGenerator extends DirectoryGenerator { /** Local name for the element that contains the included XML snippet. */ protected static final String XPATH_NODE_NAME = "xpath"; /** Attribute for the XPath query. */ protected static final String QUERY_ATTR_NAME = "query"; /** All the mapping files lastmodified dates */ protected static final Map mappingFiles = new HashMap(); /** The parser for the XML snippets to be included. */ protected DOMParser parser; /** The document that should be parsed and (partly) included. */ protected Document doc; /** The PrefixResolver responsable for processing current request (if any). */ protected PrefixResolver prefixResolver; /** The regular expression for the XML files pattern. */ protected RE xmlRE; /** The XPath. */ protected String xpath; /** The XPath processor. */ protected XPathProcessor processor; public void setParser(DOMParser parser) { this.parser = parser; } public void setXPathProcessor(XPathProcessor processor) { this.processor = processor; } /** * Disposable */ public void dispose() { if (this.manager != null) { this.manager.release(this.processor); this.manager.release(this.parser); this.processor = null; this.parser = null; } super.dispose(); } /** * Recycle resources */ public void recycle() { this.xpath = null; this.doc = null; //this.parser = null; //this.processor = null; super.recycle(); } /* (non-Javadoc) * @see org.apache.avalon.framework.service.Serviceable#service(org.apache.avalon.framework.service.ServiceManager) */ public void service(ServiceManager manager) throws ServiceException { super.service(manager); this.processor = (XPathProcessor) manager.lookup(XPathProcessor.ROLE); this.parser = (DOMParser) manager.lookup(DOMParser.class.getName()); } /** * Setup this sitemap component * * @param resolver the SourceResolver * @param objectModel The environmental object model * @param src the source attribute * @param par the parameters * * @throws ProcessingException if processing failes * @throws SAXException in case of XML related errors * @throws IOException in case of file related errors */ public void setup(SourceResolver resolver, Map objectModel, String src, Parameters par) throws ProcessingException, SAXException, IOException { super.setup(resolver, objectModel, src, par); // See if an XPath was specified this.xpath = par.getParameter("xpath", null); this.cacheKeyParList.add(this.xpath); if (getLogger().isDebugEnabled()) { getLogger().debug("Applying XPath: " + this.xpath + " to directory " + this.source); } final String mappings = par.getParameter("nsmapping", null); if (null != mappings) { final boolean mapping_reload = par.getParameterAsBoolean("nsmapping-reload", false); final Source mappingSource = resolver.resolveURI(mappings); final String mappingKey = mappingSource.getURI(); final MappingInfo mappingInfo = (MappingInfo) XPathDirectoryGenerator.mappingFiles.get(mappingKey); if ((null == mappingInfo) || (mappingInfo.reload == false) || (mappingInfo.mappingSource.getLastModified() < mappingSource.getLastModified())) { this.prefixResolver = new MappingInfo(getLogger(), mappingSource, mapping_reload); XPathDirectoryGenerator.mappingFiles.put(mappingKey, this.prefixResolver); } else { this.prefixResolver = mappingInfo; } } String xmlFilesPattern = null; try { xmlFilesPattern = par.getParameter("xmlFiles", "\\.xml$"); this.cacheKeyParList.add(xmlFilesPattern); this.xmlRE = new RE(xmlFilesPattern); if (getLogger().isDebugEnabled()) { getLogger().debug("pattern for XML files: " + xmlFilesPattern); } } catch (RESyntaxException rese) { throw new ProcessingException("Syntax error in regexp pattern '" + xmlFilesPattern + "'", rese); } } /** * Determines if a given File shall be handled as XML. * * @param path the File to check * * @return true if the given File shall handled as XML, false otherwise. */ protected boolean isXML(File path) { return this.xmlRE.match(path.getName()); } /** * Performs an XPath query on the file. * * @param xmlFile the File the XPath is performed on. * * @throws SAXException if something goes wrong while adding the XML snippet. */ protected void performXPathQuery(File xmlFile) throws SAXException { this.doc = null; Source source = null; try { source = resolver.resolveURI(xmlFile.toURL().toExternalForm()); this.doc = this.parser.parseDocument(SourceUtil.getInputSource(source)); } catch (SAXException e) { getLogger().error("Warning:" + xmlFile.getName() + " is not a valid XML file. Ignoring.", e); } catch (ProcessingException e) { getLogger().error("Warning: Problem while reading the file " + xmlFile.getName() + ". Ignoring.", e); } catch (IOException e) { getLogger().error("Warning: Problem while reading the file " + xmlFile.getName() + ". Ignoring.", e); } finally { resolver.release(source); } if (doc != null) { NodeList nl = (null == this.prefixResolver) ? this.processor.selectNodeList(this.doc.getDocumentElement(), this.xpath) : this.processor.selectNodeList(this.doc.getDocumentElement(), this.xpath, this.prefixResolver); AttributesImpl attributes = new AttributesImpl(); attributes.addAttribute("", QUERY_ATTR_NAME, QUERY_ATTR_NAME, "CDATA", xpath); super.contentHandler.startElement(URI, XPATH_NODE_NAME, PREFIX + ":" + XPATH_NODE_NAME, attributes); DOMStreamer ds = new DOMStreamer(super.xmlConsumer); for (int i = 0; i < nl.getLength(); i++) { ds.stream(nl.item(i)); } super.contentHandler.endElement(URI, XPATH_NODE_NAME, PREFIX + ":" + XPATH_NODE_NAME); } } /** * Extends the startNode() method of the DirectoryGenerator by starting a possible XPath query on a file. * * @param nodeName the node currently processing * @param path the file path * * @throws SAXException in case of errors */ protected void startNode(String nodeName, File path) throws SAXException { super.startNode(nodeName, path); if ((this.xpath != null) && path.isFile() && this.isXML(path)) { performXPathQuery(path); } } /** * The MappingInfo class to resolve namespace prefixes to their namespace URI * * @version $Id: XPathDirectoryGenerator.java 605605 2007-12-19 16:19:51Z vgritsenko $ */ private static class MappingInfo implements PrefixResolver { /** The Source of the mapping file */ public final Source mappingSource; /** Whether to reload if mapping file has changed */ public final boolean reload; /** Our Logger */ private final Log logger; /** Map of prefixes to namespaces */ private final Map prefixMap; /** * Creates a new MappingInfo object. * * @param logger DOCUMENT ME! * @param mappingSource The Source of the mapping file * @param reload Whether to reload if mapping file has changed * * @throws SourceNotFoundException In case the mentioned source is not there * @throws IOException in case the source could not be read */ public MappingInfo(final Log logger, final Source mappingSource, final boolean reload) throws SourceNotFoundException, IOException { this.logger = logger; this.mappingSource = mappingSource; this.reload = reload; prefixMap = new HashMap(); InputStreamReader input = null; BufferedReader br = null; try { input = new InputStreamReader(mappingSource.getInputStream()); br = new BufferedReader(input); for (String line = br.readLine(); line != null; line = br.readLine()) { final int i = line.indexOf('='); if (i > 0) { final String prefix = line.substring(0, i); final String namespace = line.substring(i + 1); prefixMap.put(prefix, namespace); logger.debug("added mapping: '" + prefix + "'='" + namespace + "'"); } } } finally { if (br != null) { br.close(); } if (input != null) { input.close(); } } } /* (non-Javadoc) * @see org.apache.excalibur.xml.xpath.PrefixResolver#prefixToNamespace(java.lang.String) */ public String prefixToNamespace(String prefix) { final String namespace = (String) this.prefixMap.get(prefix); if (logger.isDebugEnabled()) { logger.debug("have to resolve prefix='" + prefix + ", found namespace='" + namespace + "'"); } return namespace; } } }