com.saxonica.stream.adjunct
Class ExistsAdjunct

java.lang.Object
  extended by com.saxonica.stream.adjunct.StreamingAdjunct
      extended by 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.


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.