Package com.saxonica.ee.stream.adjunct
Class FilterFnStreamer
java.lang.Object
com.saxonica.ee.stream.adjunct.StreamingAdjunct
com.saxonica.ee.stream.adjunct.TransmissionAdjunct
com.saxonica.ee.stream.adjunct.FilteringAdjunct
com.saxonica.ee.stream.adjunct.FilterFnStreamer
- All Implemented Interfaces:
FeedMaker
- Direct Known Subclasses:
ItemsAfterStreamer
,ItemsBeforeStreamer
,ItemsFromStreamer
,ItemsUntilStreamer
Generate streaming code for the fn:filter function. Only streamable if the operand is grounded
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionstatic boolean
checkPredicateFunction
(Expression fn, List<String> reasons) computeStreamability
(ContextItemStaticInfoEE contextInfo, List<String> reasons) Compute the posture and sweep of this expression as defined in the W3C streamability specifications.makeFilter
(XPathContext context, ItemFeed out) Make a filter for the event streamMethods inherited from class com.saxonica.ee.stream.adjunct.FilteringAdjunct
makeItemFeed
Methods inherited from class com.saxonica.ee.stream.adjunct.TransmissionAdjunct
getWatchMaker, makeTransmissionFlow
Methods inherited from class com.saxonica.ee.stream.adjunct.StreamingAdjunct
emptyAdjunctMap, findConsumingArg, genId, getConfiguration, getDefaultFeedMaker, getExpression, getFeedMaker, makeStreamingAdjunct, setConfiguration, setExpression, toStreamingPattern
-
Constructor Details
-
FilterFnStreamer
public FilterFnStreamer()
-
-
Method Details
-
computeStreamability
public PostureAndSweep computeStreamability(ContextItemStaticInfoEE contextInfo, List<String> reasons) 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 classStreamingAdjunct
- Parameters:
contextInfo
- Information about the context item type and posturereasons
- 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
-
checkPredicateFunction
-
makeFilter
Make a filter for the event stream- Specified by:
makeFilter
in classFilteringAdjunct
- Parameters:
context
- the XPath dynamic contextout
- destination for the filtered output- Returns:
- a filter that can be added to the event stream
- Throws:
XPathException
- if a dynamic evaluation error occurs
-