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(Receiver next)
          Create a NamespaceReducer
 
Method Summary
 void endElement()
          endElement: Discard the namespaces declared on this element.
 String getURIForPrefix(String prefix, boolean useDefault)
          Get the namespace URI corresponding to a given prefix.
 Iterator<String> iteratePrefixes()
          Get an iterator over all the prefixes declared in this namespace context.
 void namespace(NamespaceBinding namespaceBinding, 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(NodeName elemName, SchemaType typeCode, int locationId, int properties)
          startElement.
 
Methods inherited from class net.sf.saxon.event.ProxyReceiver
append, attribute, characters, close, comment, endDocument, getNamePool, getUnderlyingReceiver, open, processingInstruction, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startDocument, usesTypeAnnotations
 
Methods inherited from class net.sf.saxon.event.SequenceReceiver
append, getConfiguration, 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(Receiver next)
Create a NamespaceReducer

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

startElement

public void startElement(NodeName elemName,
                         SchemaType 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:
elemName - 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 - if an error occurs

namespace

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

Specified by:
namespace in interface Receiver
Overrides:
namespace in class ProxyReceiver
Parameters:
namespaceBinding - the prefix/uri pair to be output
properties - the properties of the namespace binding
Throws:
XPathException - if any downstream error occurs

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 - if an error occurs

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 - if an error occurs

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<String> 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
Returns:
an iterator over all the prefixes for which a namespace binding exists, including the zero-length string to represent the null/absent prefix if it is bound


Copyright (c) 2004-2011 Saxonica Limited. All rights reserved.