## 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
`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.
`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)` 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`

Methods inherited from class net.sf.saxon.event.SequenceReceiver
`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 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`

Copyright (c) Saxonica Limited. All rights reserved.