Oracle® Database XML C API Reference 10g Release 2 (10.2) Part Number B16207-01 |
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Package Traversal contains APIs for four interfaces.
This chapter contains the following sections:
Table 8-1 summarizes the methods of available through the DocumentTraversal interface.
Table 8-1 Summary of DocumentTraversal Methods; Traversal Package
Function | Summary |
---|---|
XmlDomCreateNodeIter() |
Create node iterator object. |
XmlDomCreateTreeWalker() |
Create a tree walker object. |
One of two methods of DocumentTraversal
interface, used to create a NodeIterator
object. This method is identical to XmlDomCreateTreeWalker() except for the type of object returned.
The whatToShow
argument is a mask of flag bits, one for each node type. The value XMLDOM_SHOW_ALL
passes all node types through, otherwise only the types whose bits are set will be passed.
Entity
reference expansion is controlled by the entrefExpansion
flag. If TRUE
, entity references are replaced with their final content; if FALSE
, entity references are left as nodes.
Syntax
xmliter* XmlDomCreateNodeIter( xmlctx *xctx, xmliter *iter, xmlnode *root, xmlshowbits whatToShow, XMLDOM_ACCEPT_NODE_F( (*nodeFilter), xctx, node), boolean entrefExpand);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
iter |
IN |
existing NodeIterator to set, NULL to create |
xerr |
IN |
root node for NodeIterator |
whatToShow |
IN |
mask of XMLDOM_SHOW_ XXX flag bits |
nodeFilter |
IN |
node filter to be used, NULL if none |
xerr |
IN |
whether to expand entity reference nodes |
Returns
(xmliter *)
original or new NodeIterator
object
See Also:
XmlDomCreateTreeWalker()One of two methods of DocumentTraversal interface, used to create a TreeWalker
object. This method is identical to XmlDomCreateNodeIter() except for the type of object returned.
The whatToShow
argument is a mask of flag bits, one for each node type. The value XMLDOM_SHOW_ALL
passes all node types through, otherwise only the types whose bits are set will be passed.
Entity
reference expansion is controlled by the entrefExpansion
flag. If TRUE
, entity references are replaced with their final content; if FALSE
, entity references are left as nodes.
Syntax
xmlwalk* XmlDomCreateTreeWalker( xmlctx *xctx, xmlwalk* walker, xmlnode *root, xmlshowbits whatToShow, XMLDOM_ACCEPT_NODE_F( (*nodeFilter), xctx, node), boolean entrefExpansion);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
existing TreeWalker to set, NULL to create |
xerr |
IN |
root node for TreeWalker |
whatToShow |
IN |
mask of XMLDOM_SHOW_ XXX flag bits |
nodeFilter |
IN |
node filter to be used, NULL if none |
xerr |
IN |
whether to expand entity reference nodes |
Returns
(xmlwalk *)
new TreeWalker
object
See Also:
XmlDomCreateNodeIter()Table 8-2 summarizes the methods of available through the NodeFilter interface.
Table 8-2 Summary of NodeFileter Methods; Traversal Package
Function | Summary |
---|---|
XMLDOM_ACCEPT_NODE_F() |
Determines the filtering action based on node adn filter.. |
Sole method of NodeFilter
interface. Given a node and a filter, determines the filtering action to perform.
This function pointer is passed to the node iterator/tree walker methods, as needed.
Values for xmlerr are:
XMLERR_OK
Accept the node. Navigation methods defined for NodeIterator
or TreeWalker
will return this node.
XMLERR_FILTER_REJECT
Reject the node. Navigation methods defined for NodeIterator
or TreeWalker
will not return this node. For TreeWalker
, the children of this node will also be rejected. NodeIterator
s treat this as a synonym for XMLDOM_FILTER_SKIP
XMLERR_FILTER_SKIP
Skip this single node. Navigation methods defined for NodeIterator
or TreeWalker
will not return this node. For both NodeIterator
and TreeWalker
, the children of this node will still be considered.
Syntax
#define XMLDOM_ACCEPT_NODE_F(func, xctx, node) xmlerr func( xmlctx *xctx, xmlnode *node);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
node |
IN |
node to test |
Returns
(xmlerr)
filtering result
Table 8-3 summarizes the methods of available through the NodeIterator
interface.
Table 8-3 Summary of NodeIterator Methods; Package Traversal
Function | Summary |
---|---|
XmlDomIterDetach() |
Detach a node iterator (deactivate it). |
XmlDomIterNextNode() |
Returns next node for iterator. |
XmlDomIterPrevNode() |
Returns previous node for iterator. |
Detaches the NodeIterator
from the set which it iterated over, releasing any resources and placing the iterator in the INVALID
state. After detach has been invoked, calls to XmlDomIterNextNode
or XmlDomIterPrevNode
will raise the exception XMLERR_ITER_DETACHED
.
Syntax
xmlerr XmlDomIterDetach( xmlctx *xctx, xmliter *iter);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
iter |
IN |
node iterator object |
Returns the next node in the set and advances the position of the iterator in the set. After a node iterator is created, the first call to XmlDomIterNextNode
returns the first node in the set. It assumed that the reference node (current iterator position) is never deleted. Otherwise, changes in the underlying DOM tree do not invalidate the iterator.
Syntax
xmlnode* XmlDomIterNextNode( xmlctx *xctx, xmliter *iter, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
iter |
IN |
node iterator object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
next node in set being iterated over [or NULL
]
Returns the previous node in the set and moves the position of the iterator backward in the set.
Syntax
xmlnode* XmlDomIterPrevNode( xmlctx *xctx, xmliter *iter, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
iter |
IN |
node iterator object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
previous node in set being iterated over [or NULL
]
Table 8-4 summarizes the methods of available through the TreeWalker
interface.
Table 8-4 Summary of TreeWalker Methods; Traversal Package
Function | Summary |
---|---|
XmlDomWalkerFirstChild() |
Return first visible child of current node. |
XmlDomWalkerGetCurrentNode() |
Return current node. |
XmlDomWalkerGetRoot() |
Return root node. |
XmlDomWalkerLastChild() |
Return last visible child of current node. |
XmlDomWalkerNextNode() |
Return next visible node. |
XmlDomWalkerNextSibling() |
Return next sibling node. |
XmlDomWalkerParentNode() |
Return parent node. |
XmlDomWalkerPrevNode() |
Return previous node. |
XmlDomWalkerPrevSibling() |
Return previous sibling node. |
XmlDomWalkerSetCurrentNode() |
Set current node. |
XmlDomWalkerSetRoot() |
Set the root node. |
Moves the 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.
Syntax
xmlnode* XmlDomWalkerFirstChild( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
first visible child [or NULL
]
See Also:
XmlDomWalkerLastChild()Return (get) current node, or NULL
on error.
Syntax
xmlnode* XmlDomWalkerGetCurrentNode( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
current node
Return (get) root node, or NULL
on error. Since the current node can be removed from under the root node together with a subtree where it belongs to, the current root node in a walker might have no relation to the current node any more. The TreeWalker
iterations are based on the current node. However, the root node defines the space of an iteration. This function checks if the root node is still in the root node (ancestor) relation to the current node. If so, it returns this root node. Otherwise, it finds the root of the tree where the current node belongs to, and sets and returns this root as the root node of the walker. It returns NULL
if the walker is a NULL
pointer.
Syntax
xmlnode* XmlDomWalkerGetRoot( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
root node
Moves the 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.
Syntax
xmlnode* XmlDomWalkerLastChild( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
last visible children [or NULL
]
Moves the 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 the next node attempts to step upward from the TreeWalker
's root node, returns NULL
, and retains the current node.
Syntax
xmlnode* XmlDomWalkerNextNode( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
next node [or NULL
]
Moves the 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.
Syntax
xmlnode* XmlDomWalkerNextSibling( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
next sibling [or NULL
]
Moves to and returns the closest visible ancestor node of the current node. If the search for the parent node 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.
Syntax
xmlnode* XmlDomWalkerParentNode( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
parent node [or NULL
]
Moves the 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 the previous node attempts to step upward from the TreeWalker
's root node, returns NULL
, and retains the current node.
Syntax
xmlnode* XmlDomWalkerPrevNode( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
previous node [or NULL
]
Moves the 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.
Syntax
xmlnode* XmlDomWalkerPrevSibling( xmlctx *xctx, xmlwalk *walker, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
previous sibling [or NULL
]
Sets and returns new current node. It also checks if the root node is an ancestor of the new current node. If not it does not set the current node, returns NULL
, and sets retval to XMLDOM_WALKER_BAD_NEW_CUR
. Returns NULL
if an error.
Syntax
xmlnode* XmlDomWalkerSetCurrentNode( xmlctx *xctx, xmlwalk *walker, xmlnode *node, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
node |
IN |
new current node |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
new current node
Set the root node. Returns new root node if it is an ancestor of the current node. If not it signals an error and checks if the current root node is an ancestor of the current node. If yes it returns it. Otherwise it sets the root node to and returns the root of the tree where the current node belongs to. It returns NULL
if the walker or the root node parameter is a NULL
pointer.
Syntax
xmlnode* XmlDomWalkerSetRoot( xmlctx *xctx, xmlwalk *walker, xmlnode *node, xmlerr *xerr);
Parameter | In/Out | Description |
---|---|---|
xctx |
IN |
XML context |
walker |
IN |
TreeWalker object |
node |
IN |
new root node |
xerr |
OUT |
numeric return error code |
Returns
(xmlnode *)
new root node