com.saxonica.ee.stream.adjunct

Class TransmissionAdjunct

java.lang.Object

com.saxonica.ee.stream.adjunct.StreamingAdjunct

com.saxonica.ee.stream.adjunct.TransmissionAdjunct

All Implemented Interfaces:

FeedMaker

Direct Known Subclasses:

AdjacentTextNodeMergerAdjunct, BlockAdjunct, CardinalityCheckerAdjunct, ChooseAdjunct, ConditionalBlockAdjunct, CurrentGroupAdjunct, CurrentMergeGroupAdjunct, DocumentSorterAdjunct, FilteringAdjunct, ForEachAdjunct, InsertBeforeAdjunct, ItemCheckerAdjunct, IterateAdjunct, LetExpressionAdjunctB, TraceAdjunct, TreatFnAdjunct, TryCatchAdjunct, VennExpressionAdjunct, WherePopulatedAdjunct

public abstract class TransmissionAdjunct
extends StreamingAdjunct
implements FeedMaker

A subclass of StreamingAdjunct used for expressions that have a sequence-valued operand with usage transmission. Such expressions may appear as a filter for striding or crawling nodes, in which case they need to filter (or in some cases augment) the event stream rather than operating at the level of composed items.

Constructor Summary

Constructors

Constructor and Description
TransmissionAdjunct()

Method Summary

Methods

Modifier and Type	Method and Description
WatchMaker	getWatchMaker(boolean forGrouping) Get a WatchMaker, a factory class that creates a Watch to evaluate this expression in streaming mode.
Trigger	makeTransmissionFlow(WatchManager watchManager, Expression exp, Feed out, XPathContext context) Make a Trigger that implements this expression in streaming mode.

Methods inherited from class com.saxonica.ee.stream.adjunct.StreamingAdjunct

computeStreamability, getConfiguration, getDefaultFeedMaker, getExpression, getFeedMaker, setConfiguration, setExpression, toStreamingPattern

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.saxonica.ee.stream.feed.FeedMaker

makeItemFeed

Constructor Detail

TransmissionAdjunct

public TransmissionAdjunct()

Method Detail

getWatchMaker

public WatchMaker getWatchMaker(boolean forGrouping)
                         throws XPathException

Description copied from class: StreamingAdjunct

Get a WatchMaker, a factory class that creates a Watch to evaluate this expression in streaming mode. This method will only be called if the getImplementationMethod() method of the expression includes the value Expression.WATCH_METHOD

Overrides:

getWatchMaker in class StreamingAdjunct

Parameters:

forGrouping - true if the selected items are being grouped

Returns:

a Watchmaker to evaluate the expression, or null if it is not streamable with respect to the specificed argument.

Throws:

XPathException - in the event of a failure

makeTransmissionFlow

public Trigger makeTransmissionFlow(WatchManager watchManager,
                           Expression exp,
                           Feed out,
                           XPathContext context)
                             throws XPathException

Make a Trigger that implements this expression in streaming mode. This method is used for an expression that is striding or crawling, and it delivers a Trigger connected to a sequence of Feeds which together have the effect of delivering a sequence of events and/or items that together represent the results of this instruction. This method MUST be implemented for every expression that has an operand whose usage is transmission (and for every such operand).

Parameters:

watchManager - the WatchManager that fires this trigger

exp - the expression

out - the next action in the push pipeline for evaluation

context - the XPath dynamic context

Returns:

the Trigger (a Watch with a pattern)

Throws:

XPathException - if a dynamic evaluation error occurs.