net.sf.saxon.tree
Class TreeEnumeration

java.lang.Object
  net.sf.saxon.tree.TreeEnumeration

All Implemented Interfaces:

AxisIterator, LookaheadIterator, SequenceIterator

Direct Known Subclasses:

AncestorEnumeration, ChildEnumeration, DescendantEnumeration, FollowingEnumeration, FollowingSiblingEnumeration, PrecedingEnumeration, PrecedingOrAncestorEnumeration, PrecedingSiblingEnumeration

abstract class TreeEnumeration
extends Object
implements AxisIterator, LookaheadIterator

Field Summary

protected NodeImpl	current
protected NodeImpl	next
protected NodeTest	nodeTest
protected int	position
protected NodeImpl	start

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

ATOMIZABLE, GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD

Constructor Summary

TreeEnumeration(NodeImpl origin, NodeTest nodeTest)
Create an axis enumeration for a given type and name of node, from a given origin node

Method Summary

protected void	advance() Advance along the axis until a node is found that matches the required criteria
protected boolean	conforms(NodeImpl node) Test whether a node conforms to the node type and name constraints.
Item	current() Return the current Item
int	getProperties() Get properties of this iterator, as a bit-significant integer.
boolean	hasNext() Determine whether there are more items to come.
Item	next() Return the next node in the enumeration
int	position() Return the current position
protected abstract void	step() Advance one step along the axis: the resulting node might not meet the required criteria for inclusion

Methods inherited from class java.lang.Object

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

Methods inherited from interface net.sf.saxon.om.AxisIterator

getAnother

Field Detail

start

protected NodeImpl start

next

protected NodeImpl next

nodeTest

protected NodeTest nodeTest

current

protected NodeImpl current

position

protected int position

Constructor Detail

TreeEnumeration

public TreeEnumeration(NodeImpl origin,
                       NodeTest nodeTest)

Create an axis enumeration for a given type and name of node, from a given origin node

Parameters:

origin - the node from which the axis originates

nodeTest - test to be satisfied by the returned nodes, or null if all nodes are to be returned.

Method Detail

conforms

protected boolean conforms(NodeImpl node)

Test whether a node conforms to the node type and name constraints. Note that this returns true if the supplied node is null, this is a way of terminating a loop.

advance

protected final void advance()

Advance along the axis until a node is found that matches the required criteria

step

protected abstract void step()

Advance one step along the axis: the resulting node might not meet the required criteria for inclusion

hasNext

public boolean hasNext()

Determine whether there are more items to come. Note that this operation is stateless and it is not necessary (or usual) to call it before calling next(). It is used only when there is an explicit need to tell if we are at the last element.

Specified by:

hasNext in interface LookaheadIterator

Returns:

true if there are more items in the sequence

next

public final Item next()

Return the next node in the enumeration

Specified by:

next in interface AxisIterator

Specified by:

next in interface SequenceIterator

Returns:

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

current

public final Item current()

Return the current Item

Specified by:

current in interface AxisIterator

Specified by:

current in interface SequenceIterator

Returns:

the current item, that is, the item most recently returned by next()

position

public final int position()

Return the current position

Specified by:

position in interface AxisIterator

Specified by:

position in interface SequenceIterator

Returns:

the position of the current item (the item most recently returned by next()), starting at 1 for the first node

getProperties

public int getProperties()

Get properties of this iterator, as a bit-significant integer.

Specified by:

getProperties in interface SequenceIterator

Returns:

the properties of this iterator. This will be some combination of properties such as GROUNDED, LAST_POSITION_FINDER, and LOOKAHEAD. It is always acceptable to return the value zero, indicating that there are no known special properties. It is acceptable for the properties of the iterator to change depending on its state.