com.saxonica.stream.watch
Interface Watch

All Known Implementing Classes:

AbstractWatch, ApplyImportsWatch, ApplyTemplatesWatch, ComposingWatch, CopyOfWatch, CountWatch, EmptyWatch, EventPushingWatch, ExistsWatch, FieldWatch, ForEachComposingWatch, ForEachWatch, IterateWatch, KeySelectorWatch, NextMatchWatch, NonstreamingExpressionWatch, RefSelectorWatch, SelectorWatch, SimpleContentWatch, StringValueWatch, TypedValueWatch, VoidWatch

public interface Watch

A Watch represents a class that is interested in looking at nodes passing down a push pipeline. Originally this was for the purpose of evaluating uniqueness and key constraints while validating an instance document against a schema; now it us used for many expressions that need to be evaluated in streaming mode.

The nodes that the Watch is interested in are identified by a Selection object.

Method Summary

void	close() The close() method is called immediately before the Watch is destroyed, that is, when the element whose declaration scopes the constraint implemented by this Watch goes out of scope.
void	endSelectedParentNode(int locationId) Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.
FleetingNode	getAnchorNode() Get the anchor node for the watch.
NamespaceResolver	getNamespaceResolver() Get the namespace resolver in use by the Watch
PipelineConfiguration	getPipelineConfiguration() Get the pipeline configuration in use
Pattern	getSelection() Get the selection (that is, the restricted XPath expression) that defines the nodes that this Watch is looking for
void	notifySelectedLeafNode(FleetingNode node, int locationId) Signal that a node (other than a document or element node) that matches the selection has been found.
void	open() Open the watch.
void	setAnchorNode(FleetingNode anchor) Set the anchor node for the watch.
void	setNamespaceResolver(NamespaceResolver resolver) Set a NamespaceResolver for use by the Watch
void	setPipelineConfiguration(PipelineConfiguration pipe) Set the pipeline configuration in use
void	setSelection(Pattern selection) Set the selection (that is, the streamable XPath expression) that defines the nodes that this Watch is looking for
Receiver	startSelectedParentNode(FleetingNode node, int locationId) Signal that an element or document node has been found that matches the selection that this Watch is looking for.

Method Detail

setSelection

void setSelection(Pattern selection)

Set the selection (that is, the streamable XPath expression) that defines the nodes that this Watch is looking for

Parameters:

selection - the streamable XPath expression

getSelection

Pattern getSelection()

Get the selection (that is, the restricted XPath expression) that defines the nodes that this Watch is looking for

Returns:

the selection

setPipelineConfiguration

void setPipelineConfiguration(PipelineConfiguration pipe)

Set the pipeline configuration in use

Parameters:

pipe - the pipeline Configuration in use

getPipelineConfiguration

PipelineConfiguration getPipelineConfiguration()

Get the pipeline configuration in use

Returns:

the pipeline configuration

setNamespaceResolver

void setNamespaceResolver(NamespaceResolver resolver)

Set a NamespaceResolver for use by the Watch

Parameters:

resolver - the namespace resolver to be used

getNamespaceResolver

NamespaceResolver getNamespaceResolver()

Get the namespace resolver in use by the Watch

Returns:

the namespace resolver

setAnchorNode

void setAnchorNode(FleetingNode anchor)

Set the anchor node for the watch. This is the node to which the watch is scoped, typically the context node for the streamable path expression that defines the root of the subtree within which nodes are being sought.

Parameters:

anchor - The anchor node within which the watch is scoped

getAnchorNode

FleetingNode getAnchorNode()

Get the anchor node for the watch. This is the node to which the watch is scoped, typically the context node for the streamable path expression that defines the root of the subtree within which nodes are being sought.

Returns:

The anchor node within which the watch is scoped

open

void open()
          throws XPathException

Open the watch. This is done at the point where it first starts watching for nodes that match the selection.

Throws:

XPathException

startSelectedParentNode

Receiver startSelectedParentNode(FleetingNode node,
                                 int locationId)
                                 throws XPathException

Signal that an element or document node has been found that matches the selection that this Watch is looking for. This method is called by the WatchManager while processing the startElement or startDocument event that matches the selection.

Parameters:

node - the element or document node whose start event has been matched

locationId - the location associated with the element or document node (may be the location of the instruction that created it)

Returns:

a Receiver to be notified of all events starting with the startElement/startDocument event for the matched element, and ending with the endElement event for that element.

Throws:

ValidationException - May be raised if the constraint implemented by this Watch is violated

XPathException

endSelectedParentNode

void endSelectedParentNode(int locationId)
                           throws XPathException

Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.

Parameters:

locationId - the location of the element

Throws:

XPathException - May be raised if a constraint implemented by this Watch is violated

notifySelectedLeafNode

void notifySelectedLeafNode(FleetingNode node,
                            int locationId)
                            throws XPathException

Signal that a node (other than a document or element node) that matches the selection has been found.

Parameters:

node - the node that was matched.

locationId -

Throws:

XPathException

close

void close()
           throws XPathException

The close() method is called immediately before the Watch is destroyed, that is, when the element whose declaration scopes the constraint implemented by this Watch goes out of scope.

Throws:

XPathException