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public interface TreeWalker
TreeWalker
objects are used to navigate a document tree or
subtree using the view of the document defined by their
whatToShow
flags and filter (if any). Any function which
performs navigation using a TreeWalker
will automatically
support any view defined by a TreeWalker
.
Omitting nodes from the logical view of a subtree can result in a
structure that is substantially different from the same subtree in the
complete, unfiltered document. Nodes that are siblings in the
TreeWalker
view may be children of different, widely
separated nodes in the original view. For instance, consider a
NodeFilter
that skips all nodes except for Text nodes and
the root node of a document. In the logical view that results, all text
nodes will be siblings and appear as direct children of the root node, no
matter how deeply nested the structure of the original document.
See also the Document Object Model (DOM) Level 2 Traversal and Range Specification.
Method Summary | |
---|---|
Node |
firstChild()
Moves the TreeWalker to the first visible child of the
current node, and returns the new node. |
Node |
getCurrentNode()
The node at which the TreeWalker is currently positioned. |
boolean |
getExpandEntityReferences()
The value of this flag determines whether the children of entity reference nodes are visible to the TreeWalker . |
NodeFilter |
getFilter()
The filter used to screen nodes. |
Node |
getRoot()
The root node of the TreeWalker , as specified
when it was created. |
int |
getWhatToShow()
This attribute determines which node types are presented via the TreeWalker . |
Node |
lastChild()
Moves the TreeWalker to the last visible child of the
current node, and returns the new node. |
Node |
nextNode()
Moves the TreeWalker to the next visible node in document
order relative to the current node, and returns the new node. |
Node |
nextSibling()
Moves the TreeWalker to the next sibling of the current
node, and returns the new node. |
Node |
parentNode()
Moves to and returns the closest visible ancestor node of the current node. |
Node |
previousNode()
Moves the TreeWalker to the previous visible node in
document order relative to the current node, and returns the new
node. |
Node |
previousSibling()
Moves the TreeWalker to the previous sibling of the
current node, and returns the new node. |
void |
setCurrentNode(Node currentNode)
The node at which the TreeWalker is currently positioned. |
Method Detail |
---|
Node getRoot()
root
node of the TreeWalker
, as specified
when it was created.
int getWhatToShow()
TreeWalker
. The available set of constants is defined in
the NodeFilter
interface. Nodes not accepted by
whatToShow
will be skipped, but their children may still
be considered. Note that this skip takes precedence over the filter,
if any.
NodeFilter getFilter()
boolean getExpandEntityReferences()
TreeWalker
. If false,
these children and their descendants will be rejected. Note that
this rejection takes precedence over whatToShow
and the
filter, if any.
whatToShow
flags to hide the entity reference node
and set expandEntityReferences
to true when creating the
TreeWalker
. To produce a view of the document that has
entity reference nodes but no entity expansion, use the
whatToShow
flags to show the entity reference node and
set expandEntityReferences
to false.
Node getCurrentNode()
TreeWalker
is currently positioned.
TreeWalker
's associated filter.
currentNode
may also be explicitly set to any node,
whether or not it is within the subtree specified by the
root
node or would be accepted by the filter and
whatToShow
flags. Further traversal occurs relative to
currentNode
even if it is not part of the current view,
by applying the filters in the requested direction; if no traversal
is possible, currentNode
is not changed.
void setCurrentNode(Node currentNode) throws DOMException
TreeWalker
is currently positioned.
TreeWalker
's associated filter.
currentNode
may also be explicitly set to any node,
whether or not it is within the subtree specified by the
root
node or would be accepted by the filter and
whatToShow
flags. Further traversal occurs relative to
currentNode
even if it is not part of the current view,
by applying the filters in the requested direction; if no traversal
is possible, currentNode
is not changed.
DOMException
- NOT_SUPPORTED_ERR: Raised if an attempt is made to set
currentNode
to null
.Node parentNode()
parentNode
attempts to step
upward from the TreeWalker
's root
node, or
if it fails to find a visible ancestor node, this method retains the
current position and returns null
.
null
if the current node
has no parent in the TreeWalker
's logical view.Node firstChild()
TreeWalker
to the first visible child of the
current node, and returns the new node. If the current node has no
visible children, returns null
, and retains the current
node.
null
if the current node has no
visible children in the TreeWalker
's logical view.Node lastChild()
TreeWalker
to the last visible child of the
current node, and returns the new node. If the current node has no
visible children, returns null
, and retains the current
node.
null
if the current node has no
children in the TreeWalker
's logical view.Node previousSibling()
TreeWalker
to the previous sibling of the
current node, and returns the new node. If the current node has no
visible previous sibling, returns null
, and retains the
current node.
null
if the current node has no
previous sibling. in the TreeWalker
's logical view.Node nextSibling()
TreeWalker
to the next sibling of the current
node, and returns the new node. If the current node has no visible
next sibling, returns null
, and retains the current node.
null
if the current node has no
next sibling. in the TreeWalker
's logical view.Node previousNode()
TreeWalker
to the previous visible node in
document order relative to the current node, and returns the new
node. If the current node has no previous node, or if the search for
previousNode
attempts to step upward from the
TreeWalker
's root
node, returns
null
, and retains the current node.
null
if the current node has no
previous node in the TreeWalker
's logical view.Node nextNode()
TreeWalker
to the next visible node in document
order relative to the current node, and returns the new node. If the
current node has no next node, or if the search for nextNode attempts
to step upward from the TreeWalker
's root
node, returns null
, and retains the current node.
null
if the current node has no
next node in the TreeWalker
's logical view.
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