com.saxonica.ee.stream.adjunct

Class MergeInstrAdjunct

java.lang.Object

com.saxonica.ee.stream.adjunct.StreamingAdjunct

com.saxonica.ee.stream.adjunct.MergeInstrAdjunct

public class MergeInstrAdjunct
extends StreamingAdjunct

Streaming adjunct for the xsl:merge instruction. This is rather different from the usual run of streaming adjuncts since it is more concerned with initiating streaming than with the actual processing

Constructor Summary

Constructors

Constructor and Description
MergeInstrAdjunct()

Method Summary

Modifier and Type	Method and Description
static void	checkStreamability(MergeInstr.MergeSource mergeSource, Configuration config)
PostureAndSweep	computeStreamability(ContextItemStaticInfoEE contextInfo, java.util.List<java.lang.String> reasons) Compute the posture and sweep of this expression as defined in the W3C streamability specifications.
static java.util.List<ContextMappingIterator<ExternalObject<ItemWithMergeKeys>>>	makeSourceIterators(MergeInstr.MergeSource ms, PackageData pd, XPathContext c1) Given a streamable xsl:merge-source, return a set of iterators, one for each of the input sequences.

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

findConsumingArg, getConfiguration, getDefaultFeedMaker, getExpression, getFeedMaker, 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

MergeInstrAdjunct

public MergeInstrAdjunct()

Method Detail

checkStreamability

public static void checkStreamability(MergeInstr.MergeSource mergeSource,
                                      Configuration config)
                               throws XPathException

Throws:

XPathException

computeStreamability

public PostureAndSweep computeStreamability(ContextItemStaticInfoEE contextInfo,
                                            java.util.List<java.lang.String> reasons)

Description copied from class: StreamingAdjunct

Compute the posture and sweep of this expression as defined in the W3C streamability specifications. This must be implemented in all subclasses that don't use the general streamability rules. The implementation should have the side-effect of computing the streamability of all subexpressions, recursively.

Overrides:

computeStreamability in class StreamingAdjunct

Parameters:

contextInfo - Information about the context item type and posture

reasons - the caller may supply a list, in which case the implementation may add to this; the contents are human-readable messages explaining why the expression is not streamable.

Returns:

the posture and sweep of the expression

makeSourceIterators

public static java.util.List<ContextMappingIterator<ExternalObject<ItemWithMergeKeys>>> makeSourceIterators(MergeInstr.MergeSource ms,
                                                                                                            PackageData pd,
                                                                                                            XPathContext c1)
                                                                                                     throws XPathException

Given a streamable xsl:merge-source, return a set of iterators, one for each of the input sequences. Each iterator returns a sequence of "ItemWithMergeKeys" objects, representing an item in the streamed input sequence together with the values of its merge keys

Parameters:

ms - The merge source

pd - The containing package

c1 - The dynamic XPath Context

Returns:

a set of iterators, one for each of the sources selected by the xsl:merge-source element, containing the items delivered by this source together with their merge keys

Throws:

XPathException - if anything goes wrong