Package com.saxonica.ee.stream.feed

Class FilteringFeed

java.lang.Object

net.sf.saxon.event.Outputter

net.sf.saxon.event.ProxyOutputter

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.feed.GroundedItemFeed

com.saxonica.ee.stream.feed.FilteringFeed

All Implemented Interfaces:

Result, Receiver

public class FilteringFeed
extends GroundedItemFeed

This class selects a subset of the items, nodes, or events selected by some supplying expression. The subset is determined as a function of the position of the node (among all the nodes matched since the watch was activated).

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	FilteringFeed.Filter	Interface defining the filter function, to be implemented by the caller
static interface	FilteringFeed.FilterDelegate
static class	FilteringFeed.FilterLambda	An implementation of Filter that accepts lambda expressions (C# delegates)
static enum	FilteringFeed.FilterResult	Three possible results of the Filter#matches operation

Field Summary

Fields

Modifier and Type	Field	Description
static FilteringFeed.FilterLambda	OpaqueFilter	A filter that matches nothing
static FilteringFeed.FilterLambda	TransparentFilter	A filter that matches everything

Fields inherited from class net.sf.saxon.event.Outputter

pipelineConfiguration, systemId

Fields inherited from interface javax.xml.transform.Result

PI_DISABLE_OUTPUT_ESCAPING, PI_ENABLE_OUTPUT_ESCAPING

Constructor Summary

Constructors

Constructor	Description
FilteringFeed(WatchManager watchManager, ItemFeed nextFeed, XPathContext context, FilteringFeed.Filter filter)	Create a filtering feed

Method Summary

Modifier and Type	Method	Description
void	append(Item item)	Supply one item towards the streamed input of the expression
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.
void	open(Terminator terminator)	Start evaluating the expression.
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.GroundedItemFeed

attribute, characters, comment, endDocument, endElement, namespace, processingInstruction, setUnparsedEntity, startContent, startDocument, startElement, startElement

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

append, dynamicError, getContext, getExpression, getResultFeed, getTerminator, hasFailed, processItems, setExpression, setHasFailed, setTerminator

Methods inherited from class net.sf.saxon.event.ProxyOutputter

getNextOutputter, open, usesTypeAnnotations

Methods inherited from class net.sf.saxon.event.Outputter

getConfiguration, getPipelineConfiguration, getStringReceiver, getSystemId, namespaces, setPipelineConfiguration, setSystemId, spreadStartElement

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.event.Receiver

handlesAppend

Field Details

TransparentFilter

public static FilteringFeed.FilterLambda TransparentFilter

A filter that matches everything

OpaqueFilter

public static FilteringFeed.FilterLambda OpaqueFilter

A filter that matches nothing

Constructor Details

FilteringFeed

public FilteringFeed(WatchManager watchManager,
 ItemFeed nextFeed,
 XPathContext context,
 FilteringFeed.Filter filter)

Create a filtering feed

Parameters:

nextFeed - the feed to which the filtered items/events will be sent

filter - a function which tests whether the item/node/event at a particular position is to be selected

Method Details

open

public void open(Terminator terminator)
          throws XPathException

Description copied from class: ItemFeed

Start evaluating the expression. The default implementation does nothing.

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.

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.

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

append

public void append(Item item)
            throws XPathException

Description copied from class: ItemFeed

Supply one item towards the streamed input of the expression

Specified by:

append in interface Receiver

Specified by:

append in class ItemFeed

Parameters:

item - the item to be supplied

Throws:

XPathException - if the operation fails

close

public void close()
           throws XPathException

Description copied from class: ItemFeed

Finish evaluating the expression.

Specified by:

close in interface Receiver

Overrides:

close in class ItemFeed

Throws:

XPathException - if a dynamic error occurs