net.sf.saxon.om

Class LazySequence

java.lang.Object

net.sf.saxon.om.LazySequence

All Implemented Interfaces:

Sequence

public class LazySequence
extends Object
implements Sequence

A sequence that wraps an iterator, without being materialized. If used more than once, the input iterator is re-evaluated (which can cause problems if the client is dependent on node identity).

Constructor Summary

Constructors

Constructor and Description
LazySequence(SequenceIterator iterator) Create a virtual sequence backed by an iterator

Method Summary

Methods

Modifier and Type	Method and Description
Item	head() Get the first item in the sequence
SequenceIterator	iterate() Iterate over all the items in the sequence.

Methods inherited from class java.lang.Object

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

Constructor Detail

LazySequence

public LazySequence(SequenceIterator iterator)

Create a virtual sequence backed by an iterator

Parameters:

iterator - the iterator that delivers the items in the sequence

Method Detail

head

public Item head()
          throws XPathException

Get the first item in the sequence

Specified by:

head in interface Sequence

Returns:

the first item

Throws:

XPathException

iterate

public SequenceIterator iterate()
                         throws XPathException

Iterate over all the items in the sequence. The first time this is called it returns the original iterator backing the sequence. On subsequent calls it clones the original iterator.

Specified by:

iterate in interface Sequence

Returns:

an iterator over the items in the sequence

Throws:

XPathException - if evaluation of the iterator fails.