net.sf.saxon.tree.iter
Class AxisIteratorImpl

java.lang.Object
  extended by net.sf.saxon.tree.iter.AxisIteratorImpl
All Implemented Interfaces:
SequenceIterator, AxisIterator, UnfailingIterator
Direct Known Subclasses:
Navigator.AxisFilter, Navigator.BaseEnumeration, Navigator.EmptyTextFilter

public abstract class AxisIteratorImpl
extends Object
implements AxisIterator

A SequenceIterator is used to iterate over a sequence. An AxisIterator is a SequenceIterator that always iterates over a set of nodes, and that throws no exceptions; it also supports the ability to find the last() position, again with no exceptions. This class is an abstract implementation of AxisIterator that is used as a base class for many concrete implementations. The main functionality that it provides is maintaining the current position.


Field Summary
protected  NodeInfo current
           
protected  int position
           
 
Fields inherited from interface net.sf.saxon.om.SequenceIterator
GROUNDED, LAST_POSITION_FINDER, LOOKAHEAD
 
Constructor Summary
AxisIteratorImpl()
           
 
Method Summary
 Value atomize()
          Return the atomized value of the current node.
 void close()
          Close the iterator.
 Item current()
          Get the current node in the sequence.
 int getProperties()
          Get properties of this iterator, as a bit-significant integer.
 CharSequence getStringValue()
          Return the string value of the current node.
 AxisIterator iterateAxis(byte axis, NodeTest test)
          Return an iterator over an axis, starting at the current node.
 boolean moveNext()
          Move to the next node, without returning it.
 int position()
          Get the current position
 
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.tree.iter.UnfailingIterator
getAnother, next
 

Field Detail

position

protected int position

current

protected NodeInfo current
Constructor Detail

AxisIteratorImpl

public AxisIteratorImpl()
Method Detail

moveNext

public boolean moveNext()
Move to the next node, without returning it. Returns true if there is a next node, false if the end of the sequence has been reached. After calling this method, the current node may be retrieved using the current() function.

Specified by:
moveNext in interface AxisIterator

current

public Item current()
Get the current node in the sequence.

Specified by:
current in interface SequenceIterator
Specified by:
current in interface UnfailingIterator
Returns:
the node returned by the most recent call on next()

position

public final int position()
Get the current position

Specified by:
position in interface SequenceIterator
Specified by:
position in interface UnfailingIterator
Returns:
the position of the most recent node returned by next()

close

public void close()
Description copied from interface: SequenceIterator
Close the iterator. This indicates to the supplier of the data that the client does not require any more items to be delivered by the iterator. This may enable the supplier to release resources. After calling close(), no further calls on the iterator should be made; if further calls are made, the effect of such calls is undefined.

(Currently, closing an iterator is important only when the data is being "pushed" in another thread. Closing the iterator terminates that thread and means that it needs to do no additional work. Indeed, failing to close the iterator may cause the push thread to hang waiting for the buffer to be emptied.)

Specified by:
close in interface SequenceIterator

iterateAxis

public AxisIterator iterateAxis(byte axis,
                                NodeTest test)
Return an iterator over an axis, starting at the current node.

Specified by:
iterateAxis in interface AxisIterator
Parameters:
axis - the axis to iterate over, using a constant such as Axis.CHILD
test - a predicate to apply to the nodes before returning them.

atomize

public Value atomize()
              throws XPathException
Return the atomized value of the current node.

Specified by:
atomize in interface AxisIterator
Returns:
the atomized value.
Throws:
NullPointerException - if there is no current node
XPathException

getStringValue

public CharSequence getStringValue()
Return the string value of the current node.

Specified by:
getStringValue in interface AxisIterator
Returns:
the string value, as an instance of CharSequence.
Throws:
NullPointerException - if there is no current 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 SequenceIterator.GROUNDED, SequenceIterator.LAST_POSITION_FINDER, and SequenceIterator.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.


Copyright (c) 2004-2010 Saxonica Limited. All rights reserved.