com.saxonica.ee.stream.feed

Class ComplexNodeEventFeed

java.lang.Object

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.feed.ComplexNodeEventFeed

All Implemented Interfaces:

Feed

Direct Known Subclasses:

DocumentInstrAdjunct.DocumentInstrFeed, ElementCreatorFeed, ResultDocumentAdjunct.ResultDocumentFeed

public abstract class ComplexNodeEventFeed
extends ItemFeed

This event feed supports instructions that create a document or element node. The events representing the start and end of the element or document are written to the destination receiver during the open() and close() calls. Between these two calls, the child instruction representing the content of the document or element pushes its output to the same destination receiver.

The instruction-dependent code is contained in the processLeft() and processRight() methods

Constructor Summary

Constructors

Constructor and Description
ComplexNodeEventFeed(Expression exp, Feed parentExpressionFeed, XPathContext context)

Method Summary

Modifier and Type	Method and Description
void	close() Finish evaluating the expression.
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	open(Terminator terminator) Start evaluating the expression.
void	processItem(Item item) Supply one item towards the streamed input of the expression
protected abstract void	processLeft(XPathContext context) In streaming mode, process the first half of the instruction (for example, to start a new document or element)
protected abstract void	processRight(XPathContext context) In streaming mode, process the right half of the instruction (for example, to end a new document or element)
protected void	setReceiver(SequenceReceiver out)
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, 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

ComplexNodeEventFeed

public ComplexNodeEventFeed(Expression exp,
                            Feed parentExpressionFeed,
                            XPathContext context)

Method Detail

open

public void open(Terminator terminator)
          throws XPathException

Description copied from class: ItemFeed

Start evaluating the expression. The default implementation does nothing.

Specified by:

open in interface Feed

Overrides:

open in class ItemFeed

Parameters:

terminator - used to achieve early exit

Throws:

XPathException - if a dynamic error occurs

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

processItem

public void processItem(Item item)
                 throws XPathException

Description copied from class: ItemFeed

Supply one item towards the streamed input of the expression

Specified by:

processItem in interface Feed

Specified by:

processItem in class ItemFeed

Parameters:

item - the item to be supplied

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

close

public void close()
           throws XPathException

Description copied from class: ItemFeed

Finish evaluating the expression. The default implementation does nothing.

Specified by:

close in interface Feed

Overrides:

close in class ItemFeed

Throws:

XPathException - if a dynamic error occurs

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

setReceiver

protected void setReceiver(SequenceReceiver out)

processLeft

protected abstract void processLeft(XPathContext context)
                             throws XPathException

In streaming mode, process the first half of the instruction (for example, to start a new document or element)

Parameters:

context - The dynamic context

Throws:

XPathException - if a dynamic error occurs

processRight

protected abstract void processRight(XPathContext context)
                              throws XPathException

In streaming mode, process the right half of the instruction (for example, to end a new document or element)

Parameters:

context - The dynamic context

Throws:

XPathException - if a dynamic error occurs