com.saxonica.ee.optim

Class MultithreadedItemMappingIterator

java.lang.Object

net.sf.saxon.expr.ItemMappingIterator

com.saxonica.ee.optim.MultithreadedItemMappingIterator

All Implemented Interfaces:

LastPositionFinder, SequenceIterator, LookaheadIterator

public class MultithreadedItemMappingIterator
extends ItemMappingIterator

Parallel-processing version of the ItemMappingIterator class, which executes a mapping function for each item in a sequence. In this implementation (which is designed initially for use by the collection() function), the order of items in the result sequence retains the order of items in the input sequence.

Field Summary

Fields inherited from interface net.sf.saxon.om.SequenceIterator

ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

Constructor and Description
MultithreadedItemMappingIterator(SequenceIterator base, ItemMappingFunction action)

Method Summary

Modifier and Type	Method and Description
void	close() Close the iterator.
Item	next() Get the next item in the sequence.

Methods inherited from class net.sf.saxon.expr.ItemMappingIterator

getBaseIterator, getLength, getMappingFunction, getProperties, hasNext, isOneToOne, setOneToOne

Methods inherited from class java.lang.Object

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

Constructor Detail

MultithreadedItemMappingIterator

public MultithreadedItemMappingIterator(SequenceIterator base,
                                        ItemMappingFunction action)
                                 throws XPathException

Throws:

XPathException

Method Detail

next

public Item next()
          throws XPathException

Description copied from interface: SequenceIterator

Get the next item in the sequence. This method changes the state of the iterator.

Specified by:

next in interface SequenceIterator

Overrides:

next in class ItemMappingIterator

Returns:

the next item, or null if there are no more items. Once a call on next() has returned null, no further calls should be made. The preferred action for an iterator if subsequent calls on next() are made is to return null again, and all implementations within Saxon follow this rule.

Throws:

XPathException - if an error occurs retrieving the next item

close

public void close()

Description copied from interface: SequenceIterator

Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

Specified by:

close in interface SequenceIterator

Overrides:

close in class ItemMappingIterator