net.sf.saxon.event

Class NamespaceReducer

java.lang.Object

net.sf.saxon.event.SequenceReceiver

net.sf.saxon.event.ProxyReceiver

net.sf.saxon.event.NamespaceReducer

All Implemented Interfaces:

javax.xml.transform.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

Constructors

Constructor and Description
NamespaceReducer()

Method Summary

Modifier and Type	Method and Description
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.
java.lang.String	getURIForPrefix(java.lang.String prefix, boolean useDefault) Get the namespace URI corresponding to a given prefix.
java.util.Iterator	iteratePrefixes() Get an iterator over all the prefixes declared in this namespace context.
void	namespace(int namespaceCode, int properties) Notify a namespace.
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

attribute, characters, close, comment, endDocument, getConfiguration, getDocumentLocator, getNamePool, getUnderlyingReceiver, open, processingInstruction, setPipelineConfiguration, setSystemId, setUnderlyingReceiver, setUnparsedEntity, startDocument

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()

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

Description copied from class: ProxyReceiver

Notify a namespace. Namespaces are notified after the startElement event, and before any children for the element. The namespaces that are reported are only required to include those that are different from the parent element; however, duplicates may be reported. A namespace must not conflict with any namespaces already used for element or attribute names.

Specified by:

namespace in interface Receiver

Overrides:

namespace in class ProxyReceiver

Parameters:

namespaceCode - an integer: the top half is a prefix code, the bottom half a URI code. These may be translated into an actual prefix and URI using the name pool. A prefix code of zero represents the empty prefix (that is, the default namespace). A URI code of zero represents a URI of "", that is, a namespace undeclaration.

properties - The most important property is REJECT_DUPLICATES. If this property is set, the namespace declaration will be rejected if it conflicts with a previous declaration of the same prefix. If the property is not set, the namespace declaration will be ignored if it conflicts with a previous declaration. This reflects the fact that when copying a tree, namespaces for child elements are emitted before the namespaces of their parent element. Unfortunately this conflicts with the XSLT rule for complex content construction, where the recovery action in the event of conflicts is to take the namespace that comes last. XSLT therefore doesn't recover from this error: it sets the REJECT_DUPLICATES flag, and this is treated as a hard error.

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 java.lang.String getURIForPrefix(java.lang.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 java.util.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