com.saxonica.ee.stream.feed

Class SnapshotFeed

java.lang.Object

com.saxonica.ee.stream.feed.ItemFeed

com.saxonica.ee.stream.feed.AbsorptionFeed

com.saxonica.ee.stream.feed.SnapshotFeed

All Implemented Interfaces:

Feed

public class SnapshotFeed
extends AbsorptionFeed

This class provides streamed implementation of the snapshot() function

Nested Class Summary

Nested classes/interfaces inherited from class com.saxonica.ee.stream.feed.AbsorptionFeed

AbsorptionFeed.PendingItem

Constructor Summary

Constructors

Constructor and Description
SnapshotFeed(WatchManager watchManager, Feed result, XPathContext context)

Method Summary

Methods

Modifier and Type	Method and Description
static Trigger	getWatch(Feed result, Pattern selection, WatchManager wm, XPathContext context) Create a Watch whose effect is to create snapshots of the selected (streamed) nodes and pass them to the supplied feed
protected AbsorptionFeed.PendingItem	makePendingItem(int sequenceNr, FleetingParentNode node) Create a pending item (appropriate to the subclass) containing the data needed to compute the result value for one node in the streamed input sequence
protected Sequence	processGroundedItem(Item item) Process a grounded item in the input sequence: either a streamed leaf node such as an attribute or text node, or an atomic value, or a non-streamed element or document node injected into the sequence for example by use of the comma operator.

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

endSelectedParentNode, processItem, setHasFailed, startSelectedParentNode

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

SnapshotFeed

public SnapshotFeed(WatchManager watchManager,
            Feed result,
            XPathContext context)

Method Detail

getWatch

public static Trigger getWatch(Feed result,
               Pattern selection,
               WatchManager wm,
               XPathContext context)

Create a Watch whose effect is to create snapshots of the selected (streamed) nodes and pass them to the supplied feed

Parameters:

result - The feed to which the snapshot nodes should be supplied

selection - defines the nodes to be selected

wm - The WatchManager that will notify the selected nodes

context - the XPath evaluation context

Returns:

the new Watch

makePendingItem

protected AbsorptionFeed.PendingItem makePendingItem(int sequenceNr,
                                         FleetingParentNode node)
                                              throws XPathException

Description copied from class: AbsorptionFeed

Create a pending item (appropriate to the subclass) containing the data needed to compute the result value for one node in the streamed input sequence

Specified by:

makePendingItem in class AbsorptionFeed

Parameters:

sequenceNr - the sequence number of this node within a set of nested nodes

node - the streamed input node

Returns:

the data needed to process this node

Throws:

XPathException - if a dynamic error is detected at this stage

processGroundedItem

protected Sequence processGroundedItem(Item item)
                                throws XPathException

Description copied from class: AbsorptionFeed

Process a grounded item in the input sequence: either a streamed leaf node such as an attribute or text node, or an atomic value, or a non-streamed element or document node injected into the sequence for example by use of the comma operator.

Specified by:

processGroundedItem in class AbsorptionFeed

Parameters:

item - the grounded item

Returns:

the result of processing the grounded item

Throws:

XPathException - if a dynamic error occurs