com.saxonica.ee.stream.feed

Class CardinalityCheckingFeed

java.lang.Object

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.feed.CardinalityCheckingFeed

All Implemented Interfaces:

Feed

public class CardinalityCheckingFeed
extends ItemFeed

A Feed to go on the streaming pipeline that checks the cardinality of the sequence represented by the events passing down the pipeline. This includes the ability to handled decomposed items represented as a sequence of startElement/endElement calls.

This class handles two kinds of expression: a cardinality checker (which is generally implementing the dynamic type check required by the function conversion rules), and the "TreatFn" functions (exactly-one, zero-or-one, one-or-more) which perform a similar function but have slightly different failure semantics.

Constructor Summary

Constructors

Constructor and Description
CardinalityCheckingFeed(Expression checker, Feed result, XPathContext context)

Method Summary

Modifier and Type	Method and Description
void	close() Signal the end of the sequence of items
void	endSelectedParentNode(Location locationId) Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.
SequenceReceiver	getReceiver() Get a receiver to which start and end events for documents and elements can be written.
void	processItem(Item item) Supply an item to the feed
Receiver	startSelectedParentNode(FleetingParentNode node, Location locationId) Signal that an element or document node has been found that matches the selection that this Watch is looking for.

Methods inherited from class com.saxonica.ee.stream.feed.ItemFeed

dynamicError, getContext, getExpression, getPipelineConfiguration, getResult, getTerminator, hasFailed, open, processItems, setExpression, setHasFailed, setPipelineConfiguration, setTerminator

Methods inherited from class java.lang.Object

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

Constructor Detail

CardinalityCheckingFeed

public CardinalityCheckingFeed(Expression checker,
                               Feed result,
                               XPathContext context)

Method Detail

startSelectedParentNode

public Receiver startSelectedParentNode(FleetingParentNode node,
                                        Location locationId)
                                 throws XPathException

Description copied from class: ItemFeed

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.

Specified by:

startSelectedParentNode in interface Feed

Overrides:

startSelectedParentNode in class ItemFeed

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; or null if this feature is not required.

Throws:

XPathException - May be raised if a dynamic error occurs

endSelectedParentNode

public void endSelectedParentNode(Location locationId)
                           throws XPathException

Description copied from class: ItemFeed

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

Specified by:

endSelectedParentNode in interface Feed

Overrides:

endSelectedParentNode in class ItemFeed

Parameters:

locationId - the location of the element

Throws:

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

processItem

public void processItem(Item item)
                 throws XPathException

Supply an item to the feed

Specified by:

processItem in interface Feed

Specified by:

processItem in class ItemFeed

Parameters:

item - the item being fed

Throws:

XPathException - to report any failure

close

public void close()
           throws XPathException

Signal the end of the sequence of items

Specified by:

close in interface Feed

Overrides:

close in class ItemFeed

Throws:

XPathException - to report any failure

getReceiver

public SequenceReceiver getReceiver()

Description copied from class: ItemFeed

Get a receiver to which start and end events for documents and elements can be written.

Specified by:

getReceiver in interface Feed

Overrides:

getReceiver in class ItemFeed

Returns:

the receiver