net.sf.saxon.om

Class MemoSequence

java.lang.Object

net.sf.saxon.om.MemoSequence

All Implemented Interfaces:

Sequence

public class MemoSequence
extends Object
implements Sequence

A Sequence implementation that represents a lazy evaluation of a supplied iterator

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
class	MemoSequence.ProgressiveIterator A ProgressiveIterator starts by reading any items already held in the reservoir; when the reservoir is exhausted, it reads further items from the inputIterator, copying them into the reservoir as they are read.

Field Summary

Fields

Modifier and Type	Field and Description
protected static int	EMPTY
protected int	state

Constructor Summary

Constructors

Constructor and Description
MemoSequence(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

Field Detail

state

protected int state

EMPTY

protected static final int EMPTY

See Also:

Constant Field Values

Constructor Detail

MemoSequence

public MemoSequence(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.