com.saxonica.ee.stream.watch

Class MultiAccumulatorWatch

java.lang.Object

com.saxonica.ee.stream.watch.AbstractWatch

com.saxonica.ee.stream.watch.PatternWatch

com.saxonica.ee.stream.watch.MultiAccumulatorWatch

All Implemented Interfaces:

Watch

public class MultiAccumulatorWatch
extends PatternWatch

This watch managers a set of accumulators in streaming mode. Unlike other watches, it is called to process every node in the stream; it then checks whether any accumulator has any rule that matches this node, and if so invokes the corresponding AccumulatorWatch to update the value of the associated Accumulator

The complicating factor (see bug 4430) is that accumulators may invoke each other, and we do not know this statically. We therefore start the processing of a node/event by marking all accumulators unavailable. We then evaluate the accumulators in essentially random order. If one of them invokes another and finds it unavailable, it is then evaluated by a recursive call (with a check for cycles), and removed from the list of accumulators that are unavailable.

Constructor Summary

Constructors

Constructor and Description
MultiAccumulatorWatch(java.util.Map<Accumulator,AccumulatorWatch> accumulatorMap)

Method Summary

Modifier and Type	Method and Description
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(Location locationId) Signal that the endElement event has occurred for the element whose startElement event caused the Watch to be activated.
java.util.Map<Accumulator,AccumulatorWatch>	getAccumulatorMap()
void	open(Terminator terminator) Open the watch.
void	processItem(Item<?> item) Signal that a node (other than an element) that matches the selection has been found.
void	setWatchManager(WatchManager watchManager)
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.watch.PatternWatch

getAnchorNode, getSelection, matchesNode, matchesNodesOfKind, setAnchorNode, setSelection

Methods inherited from class com.saxonica.ee.stream.watch.AbstractWatch

getNamespaceResolver, getPipelineConfiguration, getReceiver, setNamespaceResolver, setPipelineConfiguration

Methods inherited from class java.lang.Object

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

Constructor Detail

MultiAccumulatorWatch

public MultiAccumulatorWatch(java.util.Map<Accumulator,AccumulatorWatch> accumulatorMap)

Method Detail

getAccumulatorMap

public java.util.Map<Accumulator,AccumulatorWatch> getAccumulatorMap()

open

public void open(Terminator terminator)
          throws XPathException

Description copied from class: PatternWatch

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 PatternWatch

Throws:

XPathException - May be raised if a dynamic error occurs

setWatchManager

public void setWatchManager(WatchManager watchManager)

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

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:

always null

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<?> item)
                 throws XPathException

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

Specified by:

processItem in interface Watch

Overrides:

processItem in class PatternWatch

Parameters:

item - the node that was matched.

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.

Parameters:

locationId - the location of the parsing event

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: PatternWatch

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. The default implementation does nothing.

Specified by:

close in interface Watch

Overrides:

close in class PatternWatch

Throws:

XPathException - May be raised if a dynamic error occurs