com.saxonica.stream.adjunct
Class ExistsAdjunct

java.lang.Object
  com.saxonica.stream.adjunct.StreamingAdjunct
      com.saxonica.stream.adjunct.ExistsAdjunct

public class ExistsAdjunct
extends StreamingAdjunct

Generate streaming code for an exists() function call

Constructor Summary

ExistsAdjunct()

Method Summary

WatchMaker

getWatchMaker(Expression expression, List<String> reasonsForFailure) Get a WatchMaker, a factory class that creates a Watch to evaluate this expression in streaming mode.

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

getConfiguration, getFeedMaker, makeStreamingAdjunct, setConfiguration

Methods inherited from class java.lang.Object

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

Constructor Detail

ExistsAdjunct

public ExistsAdjunct()

Method Detail

getWatchMaker

public WatchMaker getWatchMaker(Expression expression,
                                List<String> reasonsForFailure)

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:

expression - the expression to be evaluated in streaming mode

reasonsForFailure - if non-null, this is a list supplied by the caller which will be populated by the callee with one or more messages indicating why it was not possible to allocate a WatchMaker. Normally if the list is non-empty on return, the return value from the method will be null.

Returns:

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