/*
* Copyright 1999-2004 The Apache Software Foundation.
*
* Licensed 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.IOException;
import java.util.HashMap;
import java.util.Map;
import org.apache.avalon.framework.logger.Logger;
import org.apache.avalon.framework.parameters.Parameters;
import org.apache.avalon.framework.service.ServiceException;
import org.apache.avalon.framework.service.ServiceManager;
import org.apache.cocoon.ProcessingException;
import org.apache.cocoon.components.source.SourceUtil;
import org.apache.cocoon.environment.Context;
import org.apache.cocoon.environment.ObjectModelHelper;
import org.apache.cocoon.environment.SourceResolver;
import org.apache.cocoon.xml.dom.DOMStreamer;
import org.apache.excalibur.source.TraversableSource;
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.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.AttributesImpl;
/**
* Generates an XML collection listing performing XPath queries on XML sources.
* It can be used both as a plain TraversableGenerator or, if an XPath is
* specified, it will perform an XPath query on every XML resource, where "xml
* resource" is, by default, any resource ending with ".xml", which can be
* overriden by setting the (regexp) pattern "xmlFiles as a sitemap parameter,
* or where the name of the resource has a container-wide mime-type mapping to
* 'text/xml' such as specified by mime-mapping elements in a web.xml
* descriptor file.
*
* The XPath can be specified in two ways:
* <ol>
* <li>By using an XPointerish syntax in the URL: everything following the
* pound sign (possiby preceding query
* string arguments) will be treated as the XPath;
* </li>
* <li>Specifying it as a sitemap parameter named "xpath"
* </ol>
*
* Sample usage:
*
* Sitemap:
* <map:match pattern="documents/**">
* <map:generate type="xpathdirectory"
* src=" docs/{1}#/article/title|/article/abstract" >
* < map:parameter name="xmlFiles" value="\.xml$"/>
* </map:generate>
* <map: serialize type="xml" /> </map:match>
*
* Request:
* http://www.some.host/documents/test
* Result:
* <collection:collection
* name="test" lastModified="1010400942000"
* date="1/7/02 11:55 AM" requested="true"
* xmlns:collection="http://apache.org/cocoon/collection/1.0">
* <collection:collection name="subdirectory" lastModified="1010400942000" date="1/7/02 11:55 AM" />
* <collection:resource name="test.xml" lastModified="1011011579000" date="1/14/02 1:32 PM">
* <collection:xpath docid="test.xml" query="/article/title">
* <title>This is a test document</title>
* <abstract>
* <para>Abstract of my test article</para>
* </abstract>
* </collection:xpath>
* </collection:resource>
* <collection:resource name="test.gif" lastModified="1011011579000" date="1/14/02 1:32 PM">
* </collection:collection>
*
* If you need to use namespaces, you can set them as sitemap parameters in
* the form:
* lt;map:parameter name="xmlns:<i>your prefix</i>" value="nsURI"/**">
*
* @author <a href="mailto:gianugo@apache.org">Gianugo Rabellino</a>
* @author <a href="mailto:d.madama@pro-netics.com">Daniele Madama</a>
* @version CVS $Id: XPathTraversableGenerator.java,v 1.7 2004/03/27 15:41:50 unico Exp $
*/
public class XPathTraversableGenerator extends TraversableGenerator {
/** 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";
/** The document containing a successful XPath query */
protected static final String RESULT_DOCID_ATTR = "docid";
/** The regular expression for the XML files pattern. */
protected RE xmlRE = null;
/** The document that should be parsed and (partly) included. */
protected Document doc = null;
/** The XPath. */
protected String xpath = null;
/** The XPath processor. */
protected XPathProcessor processor = null;
/** The prefix resolver for namespaced queries */
protected XPathPrefixResolver prefixResolver;
/** The cocoon context used for mime-type mappings */
protected Context context;
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
int pointer;
if ((pointer = this.source.indexOf("#")) != -1) {
int endpointer = this.source.indexOf('?');
if (endpointer != -1) {
this.xpath = source.substring(pointer + 1, endpointer);
} else {
this.xpath = source.substring(pointer + 1);
}
this.source = src.substring(0, pointer);
if (endpointer != -1) {
this.source += src.substring(endpointer);
}
this.cacheKeyParList.add(this.xpath);
if (this.getLogger().isDebugEnabled())
this.getLogger().debug("Applying XPath: " + xpath
+ " to collection " + source);
} else {
this.xpath = par.getParameter("xpath", null);
this.cacheKeyParList.add(this.xpath);
this.getLogger().debug("Applying XPath: " + xpath
+ " to collection " + source);
}
String xmlFilesPattern = null;
try {
xmlFilesPattern = par.getParameter("xmlFiles", "\\.xml$");
this.cacheKeyParList.add(xmlFilesPattern);
this.xmlRE = new RE(xmlFilesPattern);
if (this.getLogger().isDebugEnabled()) {
this.getLogger().debug("pattern for XML files: " + xmlFilesPattern);
}
} catch (RESyntaxException rese) {
throw new ProcessingException("Syntax error in regexp pattern '"
+ xmlFilesPattern + "'", rese);
}
String[] params = par.getNames();
this.prefixResolver = new XPathPrefixResolver(this.getLogger());
for (int i = 0; i < params.length; i++) {
if (params[i].startsWith("xmlns:")) {
String paramValue = par.getParameter(params[i], "");
String paramName = params[i].substring(6);
if (getLogger().isDebugEnabled()) {
getLogger().debug("add param to prefixResolver: " + paramName);
}
this.prefixResolver.addPrefix(paramName, paramValue);
}
}
this.context = ObjectModelHelper.getContext(objectModel);
}
public void service(ServiceManager manager) throws ServiceException {
super.service(manager);
processor = (XPathProcessor)manager.lookup(XPathProcessor.ROLE);
}
public void dispose() {
if ( this.manager != null ) {
this.manager.release( processor );
this.processor = null;
}
super.dispose();
}
protected void addContent(TraversableSource source) throws SAXException, ProcessingException {
super.addContent(source);
if (!source.isCollection() && isXML(source) && xpath != null) {
performXPathQuery(source);
}
}
/**
* Determines if a given TraversableSource shall be handled as XML.
*
* @param path the TraversableSource to check
* @return true if the given TraversableSource shall handled as XML, false
* otherwise.
*/
protected boolean isXML(TraversableSource path) {
String mimeType = this.context.getMimeType(path.getName());
return this.xmlRE.match(path.getName()) || "text/xml".equalsIgnoreCase(mimeType);
}
/**
* Performs an XPath query on the source.
* @param in the Source the XPath is performed on.
* @throws SAXException if something goes wrong while adding the XML snippet.
*/
protected void performXPathQuery(TraversableSource in) throws SAXException {
doc = null;
try {
doc = SourceUtil.toDOM(this.manager, "text/xml", in);
} catch (SAXException se) {
this.getLogger().error("Warning:" + in.getName()
+ " is not a valid XML document. Ignoring");
} catch (Exception e) {
this.getLogger().error("Unable to resolve and parse document" + e);
}
if (doc != null) {
NodeList nl = processor.selectNodeList(doc.getDocumentElement(), xpath, this.prefixResolver);
final String id = in.getName();
AttributesImpl attributes = new AttributesImpl();
attributes.addAttribute("", RESULT_DOCID_ATTR, RESULT_DOCID_ATTR," CDATA", id);
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);
}
}
/**
* Recycle resources
*
*/
public void recycle() {
super.recycle();
this.xpath = null;
this.attributes = null;
this.doc = null;
this.xmlRE = null;
this.prefixResolver = null;
this.context = null;
}
/**
* A brain-dead PrefixResolver implementation
*
*/
class XPathPrefixResolver implements PrefixResolver {
private Map params;
private Logger logger;
public XPathPrefixResolver(Logger logger) {
this.params = new HashMap();
this.logger = logger;
}
/**
* Get a namespace URI given a prefix.
*
* @see org.apache.excalibur.xml.xpath.PrefixResolver#prefixToNamespace(java.lang.String)
*/
public String prefixToNamespace(String prefix) {
if (this.logger.isDebugEnabled()) {
this.logger.debug("prefix: " + prefix);
}
if (this.params.containsKey(prefix)) {
if(this.logger.isDebugEnabled()) {
this.logger.debug("prefix; " + prefix + " - namespace: " + this.params.get(prefix));
}
return (String) this.params.get(prefix);
}
return null;
}
public void addPrefix(String prefix, String uri) {
this.params.put(prefix, uri);
}
}
}