Package com.saxonica.ee.stream.adjunct

Class DistinctValuesStreamer

java.lang.Object

com.saxonica.ee.stream.adjunct.StreamingAdjunct

com.saxonica.ee.stream.adjunct.DistinctValuesStreamer

All Implemented Interfaces:

FeedMaker

public class DistinctValuesStreamer
extends StreamingAdjunct
implements FeedMaker

Implement the distinct-values function in streaming mode.

Constructor Summary

Constructors

Constructor	Description
DistinctValuesStreamer()

Method Summary

Modifier and Type	Method	Description
FeedMaker	getFeedMaker(int arg)	Get a FeedMaker, a factory class that creates a Feed to evaluate this expression in streaming mode.
ItemFeed	makeItemFeed(WatchManager watchManager, ItemFeed out, XPathContext context)

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

computeStreamability, emptyAdjunctMap, findConsumingArg, genId, getConfiguration, getDefaultFeedMaker, getExpression, getWatchMaker, makeStreamingAdjunct, setConfiguration, setExpression, toStreamingPattern

Methods inherited from class java.lang.Object

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

Constructor Detail

DistinctValuesStreamer

public DistinctValuesStreamer()

Method Detail

getFeedMaker

public FeedMaker getFeedMaker(int arg)

Description copied from class: StreamingAdjunct

Get a FeedMaker, a factory class that creates a Feed to evaluate this expression in streaming mode. In many cases the StreamingAdjunct is itself a FeedMaker, in which case it returns itself. But where an expression has several operands, it will typically create different feeds depending on which argument is the streamed input, and in such cases the individual StreamingAdjunct makes the decision which feed to use, by returning an appropriate FeedMaker.

Overrides:

getFeedMaker in class StreamingAdjunct

Parameters:

arg - identifies the argument with respect to which the expression is to be inverted: usually 0 to indicate the first argument is the value that is streamed. Argument numbering is the same as the sequence of arguments/operands returned by the method Expression.operands()

Returns:

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

makeItemFeed

public ItemFeed makeItemFeed(WatchManager watchManager,
                             ItemFeed out,
                             XPathContext context)
                      throws XPathException

Specified by:

makeItemFeed in interface FeedMaker

Throws:

XPathException