com.saxonica.stream
Class WatchManager

java.lang.Object
  net.sf.saxon.event.SequenceReceiver
      net.sf.saxon.event.ProxyReceiver
          com.saxonica.stream.WatchManager

All Implemented Interfaces:

Result, Receiver, NamespaceResolver

Direct Known Subclasses:

ConstraintChecker

public class WatchManager
extends ProxyReceiver
implements NamespaceResolver

This class sits on a push pipeline and evaluates the passing element and attribute nodes. One or more Watch objects can be registered with the pipeline at any time; element and attribute events are notified to the active Watch objects. A watch that is added immediately after a startElement call is automatically dropped at the corresponding endElement call. If a Watch matches a startElement call, then it becomes an active Watch; it is automatically deactivated (but not dropped) at the corresponding endElement call.

A Watch is not itself a receiver, but it can nominate a Receiver to receive all events while it is active. It will stop receiving events when it is deactivated.

Field Summary

protected Stack	activeWatchStack
protected int	elementStackTop
static List	EMPTY_WATCH_LIST
protected List	watchList

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

WatchManager()
Create a WatchManager

Method Summary

void	addWatch(Watch watch) Add a new Watch.
void	attribute(int nameCode, int typeCode, CharSequence value, int locationId, int properties) Notify an attribute
void	characters(CharSequence chars, int locationId, int properties) Text node
void	comment(CharSequence chars, int locationId, int properties) Output a comment
void	endElement() Notify end of element
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) Notify a namespace
void	processingInstruction(String target, CharSequence data, int locationId, int properties) Processing Instruction
void	startContent() Start element content (called after all the attributes and namespaces have been processed)
void	startElement(int nameCode, int typeCode, int locationId, int properties) Output element start tag
boolean	usesTypeAnnotations() Ask whether this Receiver (or the downstream pipeline) makes any use of the type annotations supplied on element and attribute events

Methods inherited from class net.sf.saxon.event.ProxyReceiver

append, close, endDocument, getConfiguration, getDocumentLocator, getNamePool, getUnderlyingReceiver, open, 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

Field Detail

elementStackTop

protected int elementStackTop

watchList

protected List watchList

activeWatchStack

protected Stack activeWatchStack

EMPTY_WATCH_LIST

public static final List EMPTY_WATCH_LIST

Constructor Detail

WatchManager

public WatchManager()

Create a WatchManager

Method Detail

startElement

public void startElement(int nameCode,
                         int typeCode,
                         int locationId,
                         int properties)
                  throws XPathException

Output element start tag

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

attribute

public void attribute(int nameCode,
                      int typeCode,
                      CharSequence value,
                      int locationId,
                      int properties)
               throws XPathException

Notify an attribute

Specified by:

attribute in interface Receiver

Overrides:

attribute in class ProxyReceiver

Parameters:

nameCode - integer identifying the name of the attribute

typeCode - integer identifying the type annotation (ignored)

value - the value of the attribute

properties - additional properties of the attribute

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.

Throws:

XPathException - On any failure to write the attribute

namespace

public void namespace(int namespaceCode,
                      int properties)
               throws XPathException

Notify a namespace

Specified by:

namespace in interface Receiver

Overrides:

namespace in class ProxyReceiver

Parameters:

namespaceCode - the namespace code (identifies the prefix and URI)

properties - properties of this event

Throws:

XPathException

characters

public void characters(CharSequence chars,
                       int locationId,
                       int properties)
                throws XPathException

Text node

Specified by:

characters in interface Receiver

Overrides:

characters in class ProxyReceiver

Parameters:

chars - The characters

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 - Bit significant value. The following bits are defined:

DISABLE_ESCAPING

Disable escaping for this text node

USE_CDATA

Output as a CDATA section

Throws:

XPathException

endElement

public void endElement()
                throws XPathException

Notify end of element

Specified by:

endElement in interface Receiver

Overrides:

endElement in class ProxyReceiver

Throws:

XPathException

comment

public void comment(CharSequence chars,
                    int locationId,
                    int properties)
             throws XPathException

Output a comment

Specified by:

comment in interface Receiver

Overrides:

comment in class ProxyReceiver

Parameters:

chars - The content of the comment

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 - Additional information about the comment. The following bits are defined:

CHECKED

Comment is known to be legal (e.g. doesn't contain "--")

Throws:

XPathException

processingInstruction

public void processingInstruction(String target,
                                  CharSequence data,
                                  int locationId,
                                  int properties)
                           throws XPathException

Processing Instruction

Specified by:

processingInstruction in interface Receiver

Overrides:

processingInstruction in class ProxyReceiver

Parameters:

target - The PI name. This must be a legal name (it will not be checked).

data - The data portion of the processing instruction

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 - Additional information about the PI. The following bits are defined:

CHECKED

Data is known to be legal (e.g. doesn't contain "?>")

Throws:

XPathException

startContent

public void startContent()
                  throws XPathException

Start element content (called after all the attributes and namespaces have been processed)

Specified by:

startContent in interface Receiver

Overrides:

startContent in class ProxyReceiver

Throws:

XPathException

addWatch

public void addWatch(Watch watch)

Add a new Watch. This is associated with the current level in the element stack, and is automatically dropped when the current element goes out of scope.

Parameters:

watch - the watch to be added

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. May be the zero-length string, indicating that there is no prefix. This indicates either the default namespace or the null namespace, depending on the value of useDefault.

useDefault - true if the default namespace is to be used when the prefix is "". If false, the method returns "" when the prefix is "".

Returns:

the uri for the namespace, or null if the prefix is not in scope. The "null namespace" is represented by the pseudo-URI "".

iteratePrefixes

public Iterator iteratePrefixes()

Description copied from interface: NamespaceResolver

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

usesTypeAnnotations

public boolean usesTypeAnnotations()

Ask whether this Receiver (or the downstream pipeline) makes any use of the type annotations supplied on element and attribute events

Specified by:

usesTypeAnnotations in interface Receiver

Overrides:

usesTypeAnnotations in class ProxyReceiver

Returns:

true if the Receiver makes any use of this information. If false, the caller may supply untyped nodes instead of supplying the type annotation