net.sf.saxon.event
Class NamespaceReducer

java.lang.Object
  extended by net.sf.saxon.event.SequenceReceiver
      extended by net.sf.saxon.event.ProxyReceiver
          extended by net.sf.saxon.event.NamespaceReducer
All Implemented Interfaces:
Result, Receiver, NamespaceResolver

public class NamespaceReducer
extends ProxyReceiver
implements NamespaceResolver

NamespaceReducer is a ProxyReceiver responsible for removing duplicate namespace declarations. It also ensures that an xmlns="" undeclaration is output when necessary. Used on its own, the NamespaceReducer simply eliminates unwanted namespace declarations. It can also be subclassed, in which case the subclass can use the services of the NamespaceReducer to resolve QNames.

The NamespaceReducer also validates namespace-sensitive content.


Field Summary
 
Fields inherited from class net.sf.saxon.event.ProxyReceiver
nextReceiver
 
Fields inherited from class net.sf.saxon.event.SequenceReceiver
pipelineConfiguration, previousAtomic, systemId
 
Fields inherited from interface javax.xml.transform.Result
PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING
 
Constructor Summary
NamespaceReducer()
          Create a NamespaceReducer
NamespaceReducer(Receiver base)
          Create a NamespaceReducer with a given destination Receiver
 
Method Summary
 void endElement()
          endElement: Discard the namespaces declared on this element.
protected  short getURICode(short prefixCode)
          Get the URI code corresponding to a given prefix code, by searching the in-scope namespaces.
 String getURIForPrefix(String prefix, boolean useDefault)
          Get the namespace URI corresponding to a given prefix.
 Iterator iteratePrefixes()
          Get an iterator over all the prefixes declared in this namespace context.
 void namespace(int namespaceCode, int properties)
          Output a namespace node (binding)
 void startContent()
          startContent: Add any namespace undeclarations needed to stop namespaces being inherited from parent elements
 void startElement(int nameCode, int typeCode, int locationId, int properties)
          startElement.
 
Methods inherited from class net.sf.saxon.event.ProxyReceiver
append, attribute, characters, close, comment, endDocument, getConfiguration, getDocumentLocator, getNamePool, getUnderlyingReceiver, open, processingInstruction, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startDocument, usesTypeAnnotations
 
Methods inherited from class net.sf.saxon.event.SequenceReceiver
append, getPipelineConfiguration, getSystemId
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

NamespaceReducer

public NamespaceReducer()
Create a NamespaceReducer


NamespaceReducer

public NamespaceReducer(Receiver base)
Create a NamespaceReducer with a given destination Receiver

Parameters:
base - the Receiver to which events will be passed after namespace reduction
Method Detail

startElement

public void startElement(int nameCode,
                         int typeCode,
                         int locationId,
                         int properties)
                  throws XPathException
startElement. This call removes redundant namespace declarations, and possibly adds an xmlns="" undeclaration.

Specified by:
startElement in interface Receiver
Overrides:
startElement in class ProxyReceiver
Parameters:
nameCode - integer code identifying the name of the element within the name pool.
typeCode - integer code identifying the element's type within the name pool.
locationId - an integer which can be interpreted using a LocationProvider to return information such as line number and system ID. If no location information is available, the value zero is supplied.
properties - properties of the element node
Throws:
XPathException

namespace

public void namespace(int namespaceCode,
                      int properties)
               throws XPathException
Output a namespace node (binding)

Specified by:
namespace in interface Receiver
Overrides:
namespace in class ProxyReceiver
Parameters:
namespaceCode - encapsulates the prefix and URI
properties - the properties of the namespace binding
Throws:
XPathException

startContent

public void startContent()
                  throws XPathException
startContent: Add any namespace undeclarations needed to stop namespaces being inherited from parent elements

Specified by:
startContent in interface Receiver
Overrides:
startContent in class ProxyReceiver
Throws:
XPathException

endElement

public void endElement()
                throws XPathException
endElement: Discard the namespaces declared on this element.

Specified by:
endElement in interface Receiver
Overrides:
endElement in class ProxyReceiver
Throws:
XPathException

getURICode

protected short getURICode(short prefixCode)
Get the URI code corresponding to a given prefix code, by searching the in-scope namespaces. This is a service provided to subclasses.

Parameters:
prefixCode - the 16-bit prefix code required
Returns:
the 16-bit URI code, or -1 if the prefix is not found

getURIForPrefix

public String getURIForPrefix(String prefix,
                              boolean useDefault)
Get the namespace URI corresponding to a given prefix. Return null if the prefix is not in scope.

Specified by:
getURIForPrefix in interface NamespaceResolver
Parameters:
prefix - the namespace prefix
useDefault - true if the default namespace is to be used when the prefix is ""
Returns:
the uri for the namespace, or null if the prefix is not in scope

iteratePrefixes

public Iterator iteratePrefixes()
Get an iterator over all the prefixes declared in this namespace context. This will include the default namespace (prefix="") and the XML namespace where appropriate

Specified by:
iteratePrefixes in interface NamespaceResolver


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.