net.sf.saxon.evpull
Class EventMappingIterator

java.lang.Object
  net.sf.saxon.evpull.EventMappingIterator

All Implemented Interfaces:

EventIterator, PullEvent

public final class EventMappingIterator
extends Object
implements EventIterator

MappingIterator merges a sequence of sequences into a single sequence. It takes as inputs an iteration, and a mapping function to be applied to each Item returned by that iteration. The mapping function itself returns another iteration. The result is an iteration of iterators. To convert this int a single flat iterator over a uniform sequence of events, the result must be wrapped in an EventStackIterator

Constructor Summary

EventMappingIterator(SequenceIterator base, EventMappingFunction action)
Construct a MappingIterator that will apply a specified MappingFunction to each Item returned by the base iterator.

Method Summary

boolean	isFlatSequence() Determine whether the EventIterator returns a flat sequence of events, or whether it can return nested event iterators
PullEvent	next() Get the next event in the sequence

Methods inherited from class java.lang.Object

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

Constructor Detail

EventMappingIterator

public EventMappingIterator(SequenceIterator base,
                            EventMappingFunction action)

Construct a MappingIterator that will apply a specified MappingFunction to each Item returned by the base iterator.

Parameters:

base - the base iterator

action - the mapping function to be applied

Method Detail

next

public PullEvent next()
               throws XPathException

Description copied from interface: EventIterator

Get the next event in the sequence

Specified by:

next in interface EventIterator

Returns:

the next event, or null when the sequence is exhausted. Note that since an EventIterator is itself a PullEvent, this method may return a nested iterator.

Throws:

XPathException - if a dynamic evaluation error occurs

isFlatSequence

public boolean isFlatSequence()

Determine whether the EventIterator returns a flat sequence of events, or whether it can return nested event iterators

Specified by:

isFlatSequence in interface EventIterator

Returns:

true if the next() method is guaranteed never to return an EventIterator