getConnection
*A helper class to build an HTTP request of the namespace URI.
* @param userAgent an optional user-agent * @param contentType an optional content-type for an accept header * @returns URLConnection */ public URLConnection getConnection() throws MalformedURLException,IOException { connection = (new URL(namespaceURI)).openConnection(); if (m_contentType != null) connection.setRequestProperty("accept",m_contentType); if (m_userAgent != null) connection.setRequestProperty("user-agent",m_userAgent); return connection; } /** * *Algorithm for obtaining resource is roughly:
*-If this is a RDDL namespace return resource of arcrole. * Well known arcroles are mapped to root namespace of resource.
*-If this is a non-RDDL namespace, and if arcrole == root namespace URI * return resource. If this provides no result match arcrole to content-type
* @param arcrole * @returns Resource * @exception AmbiguousMappingException -- more than one resource uses this arcrole */ public Resource getResource(String nature,String purpose) throws AmbiguousMappingException,IOException,SAXException { Namespace ns = RDDLURL.getNamespace(namespaceURI); Resource res = null; /* try this first */ SortedMap map = null; if (nature != null) { map = ns.getResourcesFromNature(nature); if (purpose == null) { if (map.size()==1) res = (Resource) map.get(nature); else if (map.size()>1) { throw new AmbiguousMappingException(); }; } else { Iterator iter = map.values().iterator(); while (iter.hasNext()) { Resource r = (Resource) iter.next(); if (purpose.equals(r.getPurpose())) res = r; }; }; } else if (purpose != null) { map = ns.getResourcesFromPurpose(purpose); if (nature == null) { if (map.size()==1) res = (Resource) map.get(purpose); else if (map.size()>1) { throw new AmbiguousMappingException(); }; } else { Iterator iter = map.values().iterator(); while (iter.hasNext()) { Resource r = (Resource) iter.next(); if (nature.equals(r.getNature())) res = r; }; }; }; if (res == null) { if (!bRDDLNamespace) { /*lookup content-type in well known arcrole directory (RDDL) if the content-type matches the content type of the response then return then return the identity resource (i.e. map the arcrole to the namespace URI.
*/ String contentType = (nature != null) ? Mappings.getContentTypeFromNature(nature) : null; if ((contentType != null) && (connection != null) && contentType.equals(connection.getContentType())) { map = ns.getResourcesFromNature(namespaceURI); if (map.size() == 1) res = (Resource) map.get(namespaceURI); else if (map.size() > 1) throw new AmbiguousMappingException(); }; }; }; return res; } /** * @param nsURI a namespace URI to parse as RDDL if possible */ public void parse(String nsURI) throws IOException, SAXException { InputSource insrc = new InputSource(nsURI); parse(insrc); } /** * @param insrc An InputSource to parse as RDDL if possible */ public void parse(InputSource insrc) throws IOException, SAXException { // the namespace URI is what we are parsing namespaceURI = insrc.getSystemId(); // this is because most SAX2 drivers are buggy with endElement() org.xml.sax.helpers.ParserAdapter adapt = new org.xml.sax.helpers.ParserAdapter(); XMLReader reader = (XMLReader) adapt; //XMLReaderFactory.createXMLReader(); //reader.setFeature("http://xml.org/sax/features/namespace-prefixes",true); try{ reader.setFeature("http://xml.org/sax/features/namespaces",true); } catch(Exception e) { e.printStackTrace(); throw new SAXException(e); }; /* this handler checks the namespace of the root element builds the maps in the parent as rddl:resource elemements are found */ Container cont = (Container) new AbstractContainer(namespaceURI); namespace = (Namespace) cont; RDDLHandler handler = new RDDLHandler(cont); reader.setContentHandler((ContentHandler)handler); reader.setEntityResolver((EntityResolver)this); InputStream inputStream = insrc.getByteStream(); URLConnection urlc = null; int len = s_DefaultBufferLength; if (inputStream == null) { InputSource is = resolveEntity(insrc.getPublicId(),insrc.getSystemId()); if (is == null) { urlc = getConnection(); // sets connection len = urlc.getContentLength(); if (len == -1) len = s_DefaultBufferLength; inputStream = (InputStream) new BufferedInputStream(urlc.getInputStream(),len); } else { inputStream = is.getByteStream(); } } if (!inputStream.markSupported()) inputStream = (InputStream) new BufferedInputStream(inputStream,len); inputStream.mark(len); try{ InputSource is = new InputSource(inputStream); insrc.setSystemId(namespaceURI); reader.parse(is); bRDDLNamespace = true; // this should be XHTML if we've got here contentURI = handler.rootNS; if (handler.resourceCount == 0) bRDDLNamespace = false; } catch (SAXException e) { bRDDLNamespace = false; inputStream.reset(); contentURI = handler.rootNS; }; /* now also build an identify resource which referenced the namespace URI directly for both RDDL and non-RDDL namespaces */ { String contentType = (urlc != null) ? urlc.getContentType() : null; /* nature and href are root namespace */ String role = (handler.rootNS == null) ? Mappings.MIME_URI_prefix + contentType : handler.rootNS; String href = namespaceURI; String arcrole = Mappings.RDDL_resource; ResourceImpl res = new ResourceImpl( null, // this has no id namespaceURI, // baseURI arcrole, // xlink:arcrole role, // xlink:role href, // xlink:href null, // xlink:title contentType, // contentType null, // lang null // no fragment id either ); try{ inputStream.reset(); res.inputStream = inputStream; } catch (IOException e) { res.inputStream = null; }; res.urlc = urlc; cont.addResource((Resource)res); }; } public void setFeature(String feature,boolean flag) throws org.xml.sax.SAXNotRecognizedException, org.xml.sax.SAXNotSupportedException { if (feature.equals("http://www.rddl.org/object-model#containers")) containers = flag; else super.setFeature(feature,flag); } public void setContentType(String val) { m_contentType = val; } public void setUserAgent(String val) { m_userAgent = val; } /** *namespaceURI
*The URI of the namespace we are resolving
*/ public String namespaceURI = null; /** *contentURI
*The URI of the root element of the resolved document.
*/ public String contentURI = null; protected boolean bRDDLNamespace = false; protected URLConnection connection = null; protected String m_contentType = null; protected String m_userAgent = VERSION; protected Namespace namespace = null; protected boolean containers = true; }