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)

Method Summary

Methods

Modifier and Type	Method and Description
Item	head() Get the first item in the sequence.
SequenceIterator	iterate() Get an iterator 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)

Method Detail

head

public Item head()
          throws XPathException

Description copied from interface: Sequence

Get the first item in the sequence.

Specified by:

head in interface Sequence

Returns:

the first item in the sequence if there is one, or null if the sequence is empty

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and evaluation of the first item causes a dynamic error.

iterate

public SequenceIterator iterate()
                         throws XPathException

Description copied from interface: Sequence

Get an iterator over all the items in the sequence

Specified by:

iterate in interface Sequence

Returns:

an iterator over all the items

Throws:

XPathException - in the situation where the sequence is evaluated lazily, and constructing an iterator over the items causes a dynamic error.