net.sf.saxon.tree
Class TreeEnumeration

java.lang.Object
  extended by 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 java.lang.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.