com.saxonica.stream.watch
Class CopyOfWatch

java.lang.Object
  com.saxonica.validate.AbstractWatch
      com.saxonica.stream.watch.ComposingWatch
          com.saxonica.stream.watch.CopyOfWatch

All Implemented Interfaces:

Watch

public class CopyOfWatch
extends ComposingWatch
implements Watch

This class is used when optimizing a SequentialCopy, that is, when evaluating a construct of the form saxon:stream(doc('a.xml')/a/b/c). When the matched element (c in this example) is encountered, this Watch detects the fact, and activates a Receiver to receive subsequent events and construct a tree being a copy of the subtree rooted at c. On completion, this tree is written to the supplied SequenceWriter. This will often be a Conduit, where hopefully an iterator is waiting for it on another thread.

Previously known as SubtreeCopyWatch

Constructor Summary

CopyOfWatch(Feed result, Stack<XPathContext> contextStack)

Method Summary

void	endSelectedParentNode(int locationId) Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.
void	notifySelectedLeafNode(FleetingNode node, int locationId) Signal that a node (other than an element) that matches the selection has been found.
Receiver	startSelectedParentNode(FleetingNode node, int locationId) Signal that an element has been found that matches the selection that this Watch is looking for.

Methods inherited from class com.saxonica.stream.watch.ComposingWatch

close, getContext, getContextStack, getResult, open

Methods inherited from class com.saxonica.validate.AbstractWatch

getAnchorNode, getNamespaceResolver, getPipelineConfiguration, getSelection, setAnchorNode, setNamespaceResolver, setPipelineConfiguration, setSelection

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface com.saxonica.stream.watch.Watch

close, getAnchorNode, getNamespaceResolver, getPipelineConfiguration, getSelection, open, setAnchorNode, setNamespaceResolver, setPipelineConfiguration, setSelection

Constructor Detail

CopyOfWatch

public CopyOfWatch(Feed result,
                   Stack<XPathContext> contextStack)

Method Detail

startSelectedParentNode

public Receiver startSelectedParentNode(FleetingNode node,
                                        int locationId)
                                 throws XPathException

Signal that an element has been found that matches the selection that this Watch is looking for. This method is called by the ConstraintChecker while processing the startElement event that matches the selection. For this purpose, any attributes selected by the last step in the selection are ignored

Specified by:

startSelectedParentNode in interface Watch

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 @param locationId

XPathException

notifySelectedLeafNode

public void notifySelectedLeafNode(FleetingNode node,
                                   int locationId)
                            throws XPathException

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

Specified by:

notifySelectedLeafNode in interface Watch

Overrides:

notifySelectedLeafNode in class AbstractWatch

Parameters:

node - the node that was matched.

locationId -

Throws:

XPathException

endSelectedParentNode

public 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.

Specified by:

endSelectedParentNode in interface Watch

Parameters:

locationId - the location of the element

Throws:

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

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