com.saxonica.stream.watch
Class ForEachComposingWatch

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

All Implemented Interfaces:

Watch

public class ForEachComposingWatch
extends ComposingWatch

This watch implements xsl:for-each in streaming mode, in the case where the select expression is a pattern that selects events from the streamed input, but the body of the for-each does no further downwards navigation, and delivers composed items to an ItemFeed acting as the parent expression of the for-each. It watches for the nodes selected by the xsl:for-each instruction; when such a node is encountered, it evaluates the body expression and passes its result to the parent feed. As well as an xsl:for-each instruction, this class also supports a path expression compiled as a SlashExpression, that is, one where the right-hand operand delivers atomic values. The watch is capable of handling a select expression that selects non-peer nodes (that is, one selected node that is a descendant of another). A top-level selected node is processed directly to the output receiver; a nested node is processed to create a temporary result tree, which is then appended to the output sequence when the processing of the outer selected node is complete.

Constructor Summary

ForEachComposingWatch(ContextSwitchingExpression expression, Feed result, Stack<XPathContext> contextStack)

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.
void	notifySelectedLeafNode(FleetingNode node, int locationId) Signal that a node (other than an element) that matches the selection has been found.
void	open() Open the watch.
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

getContext, getContextStack, getResult

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

Constructor Detail

ForEachComposingWatch

public ForEachComposingWatch(ContextSwitchingExpression expression,
                             Feed result,
                             Stack<XPathContext> contextStack)

Method Detail

open

public void open()
          throws XPathException

Description copied from class: ComposingWatch

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

Specified by:

open in interface Watch

Overrides:

open in class ComposingWatch

Throws:

XPathException

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 WatchManager while processing the startElement event that matches the selection. For this purpose, any attributes selected by the last step in the selection are ignored

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.

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

close

public void close()
           throws XPathException

Description copied from class: ComposingWatch

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.

Specified by:

close in interface Watch

Overrides:

close in class ComposingWatch

Throws:

XPathException