com.saxonica.ee.stream.adjunct

Class InspectionAdjunct

java.lang.Object

com.saxonica.ee.stream.adjunct.StreamingAdjunct

com.saxonica.ee.stream.adjunct.InspectionAdjunct

Direct Known Subclasses:

AccumulatorAfterStreamer, BooleanFnStreamer, CountStreamer, EmptyStreamer, ExistsStreamer, InstanceOfAdjunct, NotFnStreamer

public abstract class InspectionAdjunct
extends StreamingAdjunct

Abstract superclass for constructs that have operand usage "inspection" on their primary (sequence-valued) operand

Constructor Summary

Constructors

Constructor and Description
InspectionAdjunct()

Method Summary

Modifier and Type	Method and Description
protected WatchMaker	getInspectionWatchMaker(Expression parent, Expression select, boolean forGrouping) This is a utility method for subclasses; it provides a WatchMaker suitable for all constructs that perform inspection on a sequence, for example exists(), count(), empty(), boolean(), not(), instanceOf.
WatchMaker	getWatchMaker(boolean forGrouping) Get a WatchMaker, a factory class that creates a Watch to evaluate this expression in streaming mode.

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

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

Methods inherited from class java.lang.Object

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

Constructor Detail

InspectionAdjunct

public InspectionAdjunct()

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

getInspectionWatchMaker

protected final WatchMaker getInspectionWatchMaker(Expression parent,
                                                   Expression select,
                                                   boolean forGrouping)
                                            throws XPathException

This is a utility method for subclasses; it provides a WatchMaker suitable for all constructs that perform inspection on a sequence, for example exists(), count(), empty(), boolean(), not(), instanceOf.

Parameters:

parent - the expression, typically one of the above function calls

select - the argument to the inspection construct, typically the first argument of one of the above function calls

forGrouping -

Returns:

a WatchMaker that feeds the selected nodes (as FleetingNode instances) to the Feed provided by this construct. Because this is an inspection construct, it is assumed able to compute the result by looking at the FleetingNode objects alone.

Throws:

XPathException - in the event of a dynamic error.