net.sf.saxon.om

Class Navigator.BaseEnumeration

Enclosing Class:
Navigator
Implemented Interfaces:
AxisIterator, SequenceIterator, UnfailingIterator
Known Direct Subclasses:
Navigator.AncestorEnumeration, Navigator.DescendantEnumeration, Navigator.FollowingEnumeration, Navigator.PrecedingEnumeration

public static abstract class Navigator.BaseEnumeration
extends AxisIteratorImpl

BaseEnumeration is an abstract implementation of an AxisIterator, it simplifies the implementation of the underlying AxisIterator by requiring it to provide only two methods: advance(), and getAnother().

NOTA BENE: BaseEnumeration does not maintain the value of the position variable. It must therefore either (a) be wrapped in an AxisFilter, which does maintain position, or (b) be subclassed by a class that maintains position itself.

Field Summary

Fields inherited from class net.sf.saxon.om.AxisIteratorImpl

current, position

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Method Summary

abstract void
advance()
The advance() method must be provided in each concrete implementation.
abstract SequenceIterator
getAnother()
Get another iterator over the same sequence of items, positioned at the start of the sequence.
Item
next()
Get the next item in the sequence.

Methods inherited from class net.sf.saxon.om.AxisIteratorImpl

atomize, current, getProperties, getStringValue, iterateAxis, moveNext, position

Method Details

advance

public abstract void advance()
The advance() method must be provided in each concrete implementation. It must leave the variable current set to the next node to be returned in the iteration, or to null if there are no more nodes to be returned.

getAnother

public abstract SequenceIterator getAnother()
Get another iterator over the same sequence of items, positioned at the start of the sequence. It must be possible to call this method at any time, whether none, some, or all of the items in the original iterator have been read. The method is non-destructive: it does not change the state of the original iterator.
Specified by:
getAnother in interface UnfailingIterator
getAnother in interface SequenceIterator
Returns:
a new iterator over the same sequence

next

public final Item next()
Get the next item in the sequence.
Specified by:
next in interface UnfailingIterator
next in interface SequenceIterator
Returns:
the next Item. If there are no more nodes, return null.