com.saxonica.ee.stream

Class SequenceExchanger.Consumer

java.lang.Object

com.saxonica.ee.stream.SequenceExchanger.Consumer

All Implemented Interfaces:

SequenceIterator

Enclosing class:

SequenceExchanger

public static class SequenceExchanger.Consumer
extends Object
implements SequenceIterator

The Consumer is a SequenceIterator that reads a sequence of items from the Conduit: that is, it allows its caller to make a sequence of calls on next(), each of which will return the next item pushed onto the Conduit by the corresponding Producer.

Field Summary

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

ATOMIZING, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Constructors

Constructor and Description
SequenceExchanger.Consumer(Conduit conduit, SequenceExchanger.Producer producer) Create a consumer

Method Summary

Methods

Modifier and Type	Method and Description
void	close() Close the iterator.
SequenceIterator	getAnother() Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.
int	getProperties() Get properties of this iterator, as a bit-significant integer.
Item	next() Get the next item in the sequence.

Methods inherited from class java.lang.Object

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

Constructor Detail

SequenceExchanger.Consumer

public SequenceExchanger.Consumer(Conduit conduit,
                          SequenceExchanger.Producer producer)

Create a consumer

Parameters:

conduit - The conduit from which items are to be read

producer - The producer supplying items to the conduit. This is needed in case the sequence needs to be re-read, which can happen when calling last().

Method Detail

getAnother

public SequenceIterator getAnother()
                            throws XPathException

Get another SequenceIterator that iterates over the same items as the original, but which is repositioned at the start of the sequence.

This method allows access to all the items in the sequence without disturbing the current position of the iterator. Internally, its main use is in evaluating the last() function.

This method does not change the state of the iterator.

Specified by:

getAnother in interface SequenceIterator

Returns:

a SequenceIterator that iterates over the same items, positioned before the first item

Throws:

XPathException - if any error occurs

Since:

8.4

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator

Returns:

the properties of this iterator. This will be some combination of properties such as SequenceIterator.GROUNDED and SequenceIterator.LAST_POSITION_FINDER. It is always acceptable to return the value zero, indicating that there are no known special properties.

next

public Item next()
          throws XPathException

Get the next item in the sequence. This method changes the state of the iterator, in particular it affects the result of subsequent calls of position() and current().

Specified by:

next in interface SequenceIterator

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

Since:

8.4

close

public void close()

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. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

Specified by:

close in interface SequenceIterator