org.apache.cocoon.xml.dom
Class DOMStreamer.NamespaceNormalizingDOMStreamer

java.lang.Object
  org.apache.avalon.framework.logger.AbstractLogEnabled
      org.apache.cocoon.xml.AbstractXMLProducer
          org.apache.cocoon.xml.dom.DOMStreamer.NamespaceNormalizingDOMStreamer

All Implemented Interfaces:

Poolable, Recyclable, LogEnabled, XMLProducer

Enclosing class:

DOMStreamer

public static class DOMStreamer.NamespaceNormalizingDOMStreamer
extends AbstractXMLProducer

Streams a DOM tree to SAX events and normalizes namespace declarations on the way.

The code in this class is based on the org.apache.xml.utils.TreeWalker class from Xalan, though it differs in some important ways.

This class will automatically fix up ("normalize") namespace declarations while streaming to SAX. The original DOM-tree is not modified. The algorithm used is described in an appendix of the DOM Level 3 spec.

This class will NOT check the correctness of namespaces, e.g. it will not check that the "xml" prefix is not misused etc.

Author:

Bruno Dumon (bruno at outerthought dot org), Xalan team

Nested Class Summary

static class

DOMStreamer.NamespaceNormalizingDOMStreamer.ElementInfo

Field Summary

protected DOMStreamer.NamespaceNormalizingDOMStreamer.ElementInfo	currentElementInfo Information about the current element.
protected int	newPrefixCounter Counter used when generating new namespace prefixes.

Fields inherited from class org.apache.cocoon.xml.AbstractXMLProducer

contentHandler, EMPTY_CONTENT_HANDLER, lexicalHandler, xmlConsumer

Constructor Summary

DOMStreamer.NamespaceNormalizingDOMStreamer()

Method Summary

protected void	endNode(Node node) End processing of given node
String	getNamespaceForPrefix(String prefix, Element namespaceContext) Searches the namespace for a given namespace prefix starting from a given Element.
void	recycle() Recycle the producer by removing references, and resetting handlers to null (empty) implementations.
protected void	startNode(Node node) Start processing given node
protected void	stream(Node pos) Start the production of SAX events.

Methods inherited from class org.apache.cocoon.xml.AbstractXMLProducer

setConsumer, setContentHandler, setLexicalHandler

Methods inherited from class org.apache.avalon.framework.logger.AbstractLogEnabled

enableLogging, getLogger, setupLogger, setupLogger, setupLogger

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

currentElementInfo

protected DOMStreamer.NamespaceNormalizingDOMStreamer.ElementInfo currentElementInfo

Information about the current element. Used to remember the localName, qName and namespaceURI for generating the endElement event, and holds the namespaces declared on the element. This extra class is needed because we don't want to modify the DOM-tree itself. The currentElementInfo has a pointer to its parent elementInfo.

newPrefixCounter

protected int newPrefixCounter

Counter used when generating new namespace prefixes.

Constructor Detail

DOMStreamer.NamespaceNormalizingDOMStreamer

public DOMStreamer.NamespaceNormalizingDOMStreamer()

Method Detail

recycle

public void recycle()

Description copied from class: AbstractXMLProducer

Recycle the producer by removing references, and resetting handlers to null (empty) implementations.

Specified by:

recycle in interface Recyclable

Overrides:

recycle in class AbstractXMLProducer

stream

protected void stream(Node pos)
               throws SAXException

Start the production of SAX events.

Perform a pre-order traversal non-recursive style.

Note that TreeWalker assumes that the subtree is intended to represent a complete (though not necessarily well-formed) document and, during a traversal, startDocument and endDocument will always be issued to the SAX listener.

Parameters:

pos - Node in the tree where to start traversal

Throws:

SAXException

startNode

protected void startNode(Node node)
                  throws SAXException

Start processing given node

Parameters:

node - Node to process

Throws:

SAXException

getNamespaceForPrefix

public String getNamespaceForPrefix(String prefix,
                                    Element namespaceContext)

Searches the namespace for a given namespace prefix starting from a given Element.

Note that this resolves the prefix in the orginal DOM-tree, not in the DOMStreamer.NamespaceNormalizingDOMStreamer.ElementInfo objects. This is used to resolve prefixes of elements or attributes created with createElement or setAttribute instead of createElementNS or setAttributeNS.

The code in this method is largely based on org.apache.xml.utils.DOMHelper.getNamespaceForPrefix() (from Xalan).

Parameters:

prefix - the prefix to look for, can be empty or null to find the default namespace

Returns:

the namespace, or null if not found.

endNode

protected void endNode(Node node)
                throws SAXException

End processing of given node

Parameters:

node - Node we just finished processing

Throws:

SAXException