net.sf.saxon.tree.util
Class Navigator.BaseEnumeration

java.lang.Object
  net.sf.saxon.tree.iter.AxisIteratorImpl
      net.sf.saxon.tree.util.Navigator.BaseEnumeration

All Implemented Interfaces:

SequenceIterator, AxisIterator, UnfailingIterator

Direct Known Subclasses:

Navigator.AncestorEnumeration, Navigator.DescendantEnumeration, Navigator.FollowingEnumeration, Navigator.PrecedingEnumeration

Enclosing class:

Navigator

public abstract static 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().

BaseEnumeration takes responsibility for incrementing position when next() is called. The advance() method in a subclass should therefore not modify position.

Field Summary

Fields inherited from class net.sf.saxon.tree.iter.AxisIteratorImpl

current, position

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

GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

Navigator.BaseEnumeration()

Method Summary

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

Methods inherited from class net.sf.saxon.tree.iter.AxisIteratorImpl

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

Methods inherited from class java.lang.Object

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

Constructor Detail

Navigator.BaseEnumeration

public Navigator.BaseEnumeration()

Method Detail

next

public final NodeInfo next()

Description copied from interface: UnfailingIterator

Get the next item in the sequence.

Returns:

the next Item. If there are no more nodes, return null.

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 AxisIterator getAnother()

Description copied from interface: UnfailingIterator

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.

Returns:

a new iterator over the same sequence