org.jaxen.util
Class PrecedingAxisIterator
java.lang.Object
org.jaxen.util.PrecedingAxisIterator
- Iterator
public class PrecedingAxisIterator
extends java.lang.Object
implements Iterator
Represents the XPath
preceding
axis.
The "
preceding
axis contains all nodes in the same document as the context
node that are before the context node in document order, excluding any ancestors
and excluding attribute nodes and namespace nodes."
This implementation of '
preceding
' works like so:
the
preceding
axis includes preceding siblings of this node and
their descendants. Also, for each ancestor node of this node, it includes
all preceding siblings of that ancestor, and their descendants. Finally, it
includes the ancestor nodes themselves.
The reversed
descendant-or-self
axes that are required are calculated using a
stack of reversed 'child-or-self' axes. When asked for a node, it is always taken
from a child-or-self axis. If it was the last node on that axis, the node is returned.
Otherwise, this axis is pushed on the stack, and the process is repeated with the child-or-self
of the node. Eventually this recurses down to the last descendant of any node, then works
back up to the root.
Most object models could provide a faster implementation of the reversed
'children-or-self' used here.
private ListIterator | childrenOrSelf(Object node)
|
boolean | hasNext() - Returns true if there are any preceding nodes remaining; false otherwise.
|
Object | next() - Returns the next preceding node.
|
void | remove() - This operation is not supported.
|
ancestorOrSelf
private Iterator ancestorOrSelf
childrenOrSelf
private ListIterator childrenOrSelf
precedingSibling
private Iterator precedingSibling
stack
private ArrayList stack
PrecedingAxisIterator
public PrecedingAxisIterator(Object contextNode,
Navigator navigator)
throws UnsupportedAxisException
Create a new preceding
axis iterator.
contextNode
- the node to start fromnavigator
- the object model specific navigator
childrenOrSelf
private ListIterator childrenOrSelf(Object node)
hasNext
public boolean hasNext()
Returns true if there are any preceding nodes remaining; false otherwise.
- true if any preceding nodes remain; false otherwise
java.util.Iterator.hasNext()
next
public Object next()
throws NoSuchElementException
Returns the next preceding node.
java.util.Iterator.next()
remove
public void remove()
throws UnsupportedOperationException
This operation is not supported.