com.saxonica.ee.stream.watch

Class ForEachAction

java.lang.Object

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.watch.ForEachAction

All Implemented Interfaces:

Feed

Direct Known Subclasses:

ForEachGroupParallelAction, IterateAction

public class ForEachAction
extends ItemFeed

This watch implements xsl:for-each in streaming mode. It is informed of the nodes or other items selected by the xsl:for-each instruction; when such an item is encountered, it locates the relevant (inverted) action representing the body of the for-each, and activates it.

The feed 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.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	ForEachAction.Activation An activation represents an occurrence of a node that matches the selection, whose start tag has been encountered and whose end tag has not yet been encountered.

Field Summary

Fields

Modifier and Type	Field and Description
protected XPathContext	bodyContext

Constructor Summary

Constructors

Constructor and Description
ForEachAction(WatchManager watchManager, Expression expression, Feed result, 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.
protected Expression	getAction()
protected java.util.Stack<ForEachAction.Activation>	getActivationStack()
protected XPathContext	getBodyContext()
protected Inversion	getInversion()
SequenceReceiver	getReceiver() Get a receiver to which start and end events for documents and elements can be written.
protected java.util.List<Sequence<?>>	getValuesAwaitingOutput()
protected WatchManager	getWatchManager()
protected boolean	isActionConsuming()
protected void	makeBodyContext()
void	open(Terminator terminator) Start evaluating the expression.
void	processItem(Item<?> it) Method called by the feed for a subexpression to supply a grounded item from the streamed input.
void	setInversion(Inversion inversion) Set the inversion of the for-each action (the body of the loop)
Receiver	startSelectedParentNode(FleetingParentNode node, Location locationId) Signal that an element 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

Field Detail

bodyContext

protected XPathContext bodyContext

Constructor Detail

ForEachAction

public ForEachAction(WatchManager watchManager,
                     Expression expression,
                     Feed result,
                     XPathContext context)

Method Detail

setInversion

public void setInversion(Inversion inversion)

Set the inversion of the for-each action (the body of the loop)

Parameters:

inversion - the inverted code implementing the body of the for-each

getInversion

protected Inversion getInversion()

getWatchManager

protected WatchManager getWatchManager()

getAction

protected Expression getAction()

isActionConsuming

protected boolean isActionConsuming()

getBodyContext

protected XPathContext getBodyContext()

getActivationStack

protected java.util.Stack<ForEachAction.Activation> getActivationStack()

getValuesAwaitingOutput

protected java.util.List<Sequence<?>> getValuesAwaitingOutput()

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

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

makeBodyContext

protected void makeBodyContext()

startSelectedParentNode

public Receiver startSelectedParentNode(FleetingParentNode node,
                                        Location 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

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:

ValidationException - May be raised if the constraint implemented by this Watch is violated @param locationId the location of the node in the source, or of the instruction that created it

XPathException - May be raised if a dynamic error occurs

processItem

public void processItem(Item<?> it)
                 throws XPathException

Method called by the feed for a subexpression to supply a grounded item from the streamed input.

Specified by:

processItem in interface Feed

Specified by:

processItem in class ItemFeed

Parameters:

it - the grounded item.

Throws:

XPathException - May be raised if a dynamic error occurs

endSelectedParentNode

public void endSelectedParentNode(Location 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 Feed

Overrides:

endSelectedParentNode in class ItemFeed

Parameters:

locationId - the location of the node in the source, or of the instruction that created it

Throws:

ValidationException - May be raised if the constraint implemented by this Watch is violated @param locationId the location of the node in the source, or of the instruction that created it

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