* This is a SAX filter which resolves all XInclude include elements * before passing them on to the client application. Currently this * class has the following known deviation from the XInclude specification: *
** Furthermore, I would definitely use a new instance of this class * for each document you want to process. I doubt it can be used * successfully on multiple documents. Furthermore, I can virtually * guarantee that this class is not thread safe. You have been * warned. *
* ** Since this class is not designed to be subclassed, and since * I have not yet considered how that might affect the methods * herein or what other protected methods might be needed to support * subclasses, I have declared this class final. I may remove this * restriction later, though the use-case for subclassing is weak. * This class is designed to have its functionality extended via a * a horizontal chain of filters, not a * vertical hierarchy of sub and superclasses. *
* ** To use this class: *
*XIncludeFilter object with a known base URLXMLReader object from which the raw document will
* be read to the setParent() method of this object. ContentHandler object to the
* setContentHandler() method of this object. This is the
* object which will receive events from the parsed and included
* document.
* LexicalHandler object as the value of this object's
* http://xml.org/sax/properties/lexical-handler property.
* Also make sure your LexicalHandler asks this object
* for the status of each comment using insideIncludeElement
* before doing anything with the comment.
* parse() methode.g.
*XIncludeFilter includer = new XIncludeFilter(base);
* includer.setParent(parser);
* includer.setContentHandler(new SAXXIncluder(System.out));
* includer.parse(args[i]);
* * This utility method returns true if and only if this reader is * currently inside a non-empty include element. (This is * not the same as being inside the node set whihc replaces * the include element.) This is primarily needed for comments * inside include elements. It must be checked by the actual * LexicalHandler to see whether a comment is passed or not. *
* * @return boolean */ public boolean insideIncludeElement() { return level != 0; } public void startElement(String uri, String localName, String qName, Attributes atts) throws SAXException { if (level == 0) { // We're not inside an xi:include element // Adjust bases stack by pushing either the new // value of xml:base or the base of the parent String base = atts.getValue(NamespaceSupport.XMLNS, "base"); URL parentBase = (URL) bases.peek(); URL currentBase = parentBase; if (base != null) { try { currentBase = new URL(parentBase, base); } catch (MalformedURLException e) { throw new SAXException("Malformed base URL: " + currentBase, e); } } bases.push(currentBase); if (uri.equals(XINCLUDE_NAMESPACE) && localName.equals("include")) { // include external document String href = atts.getValue("href"); // Verify that there is an href attribute if (href==null) { throw new SAXException("Missing href attribute"); } String parse = atts.getValue("parse"); if (parse == null) parse = "xml"; if (parse.equals("text")) { String encoding = atts.getValue("encoding"); includeTextDocument(href, encoding); } else if (parse.equals("xml")) { includeXMLDocument(href); } // Need to check this also in DOM and JDOM???? else { throw new SAXException( "Illegal value for parse attribute: " + parse); } level++; } else { super.startElement(uri, localName, qName, atts); } } } public void endElement (String uri, String localName, String qName) throws SAXException { if (uri.equals(XINCLUDE_NAMESPACE) && localName.equals("include")) { level--; } else if (level == 0) { bases.pop(); super.endElement(uri, localName, qName); } } private int depth = 0; public void startDocument() throws SAXException { level = 0; if (depth == 0) super.startDocument(); depth++; } public void endDocument() throws SAXException { locators.pop(); depth--; if (depth == 0) super.endDocument(); } // how do prefix mappings move across documents???? public void startPrefixMapping(String prefix, String uri) throws SAXException { if (level == 0) super.startPrefixMapping(prefix, uri); } public void endPrefixMapping(String prefix) throws SAXException { if (level == 0) super.endPrefixMapping(prefix); } public void characters(char[] ch, int start, int length) throws SAXException { if (level == 0) super.characters(ch, start, length); } public void ignorableWhitespace(char[] ch, int start, int length) throws SAXException { if (level == 0) super.ignorableWhitespace(ch, start, length); } public void processingInstruction(String target, String data) throws SAXException { if (level == 0) super.processingInstruction(target, data); } public void skippedEntity(String name) throws SAXException { if (level == 0) super.skippedEntity(name); } // convenience method for error messages private String getLocation() { String locationString = ""; Locator locator = (Locator) locators.peek(); String publicID = ""; String systemID = ""; int column = -1; int line = -1; if (locator != null) { publicID = locator.getPublicId(); systemID = locator.getSystemId(); line = locator.getLineNumber(); column = locator.getColumnNumber(); } locationString = " in document included from " + publicID + " at " + systemID + " at line " + line + ", column " + column; return locationString; } /** *
* This utility method reads a document at a specified URL
* and fires off calls to characters().
* It's used to include files with parse="text"
*
* This utility method reads a document at a specified URL
* and fires off calls to various ContentHandler methods.
* It's used to include files with parse="xml"
*