LSParserFilter
public
interface
LSParserFilter
| org.w3c.dom.ls.LSParserFilter |
LSParserFilters provide applications the ability to examine
nodes as they are being constructed while parsing. As each node is
examined, it may be modified or removed, or the entire parse may be
terminated early.
At the time any of the filter methods are called by the parser, the
owner Document and DOMImplementation objects exist and are accessible.
The document element is never passed to the LSParserFilter
methods, i.e. it is not possible to filter out the document element.
Document, DocumentType, Notation,
Entity, and Attr nodes are never passed to the
acceptNode method on the filter. The child nodes of an
EntityReference node are passed to the filter if the
parameter "
entities" is set to false. Note that, as described by the parameter "
entities", unexpanded entity reference nodes are never discarded and are always
passed to the filter.
All validity checking while parsing a document occurs on the source document as it appears on the input stream, not on the DOM document as it is built in memory. With filters, the document in memory may be a subset of the document on the stream, and its validity may have been affected by the filtering.
All default attributes must be present on elements when the elements are passed to the filter methods. All other default content must be passed to the filter methods.
DOM applications must not raise exceptions in a filter. The effect of throwing exceptions from a filter is DOM implementation dependent.
See also the Document Object Model (DOM) Level 3 Load and Save Specification.
Summary
Constants | |
|---|---|
short |
FILTER_ACCEPT
Accept the node. |
short |
FILTER_INTERRUPT
Interrupt the normal processing of the document. |
short |
FILTER_REJECT
Reject the node and its children. |
short |
FILTER_SKIP
Skip this single node. |
Public methods | |
|---|---|
abstract
short
|
acceptNode(Node nodeArg)
This method will be called by the parser at the completion of the parsing of each node. |
abstract
int
|
getWhatToShow()
Tells the |
abstract
short
|
startElement(Element elementArg)
The parser will call this method after each |
Constants
FILTER_ACCEPT
public static final short FILTER_ACCEPT
Accept the node.
Constant Value: 1 (0x00000001)
FILTER_INTERRUPT
public static final short FILTER_INTERRUPT
Interrupt the normal processing of the document.
Constant Value: 4 (0x00000004)
FILTER_REJECT
public static final short FILTER_REJECT
Reject the node and its children.
Constant Value: 2 (0x00000002)
FILTER_SKIP
public static final short FILTER_SKIP
Skip this single node. The children of this node will still be considered.
Constant Value: 3 (0x00000003)
Public methods
acceptNode
public abstract short acceptNode (Node nodeArg)
This method will be called by the parser at the completion of the
parsing of each node. The node and all of its descendants will exist
and be complete. The parent node will also exist, although it may be
incomplete, i.e. it may have additional children that have not yet
been parsed. Attribute nodes are never passed to this function.
From within this method, the new node may be freely modified -
children may be added or removed, text nodes modified, etc. The state
of the rest of the document outside this node is not defined, and the
affect of any attempt to navigate to, or to modify any other part of
the document is undefined.
For validating parsers, the checks are made on the original
document, before any modification by the filter. No validity checks
are made on any document modifications made by the filter.
If this new node is rejected, the parser might reuse the new node
and any of its descendants.
| Parameters | |
|---|---|
nodeArg |
Node: The newly constructed element. At the time this method
is called, the element is complete - it has all of its children
(and their children, recursively) and attributes, and is attached
as a child to its parent. |
| Returns | |
|---|---|
short |
|
getWhatToShow
public abstract int getWhatToShow ()
Tells the LSParser what types of nodes to show to the
method LSParserFilter.acceptNode. If a node is not shown
to the filter using this attribute, it is automatically included in
the DOM document being built. See NodeFilter for
definition of the constants. The constants SHOW_ATTRIBUTE
, SHOW_DOCUMENT, SHOW_DOCUMENT_TYPE,
SHOW_NOTATION, SHOW_ENTITY, and
SHOW_DOCUMENT_FRAGMENT are meaningless here. Those nodes
will never be passed to LSParserFilter.acceptNode.
The constants used here are defined in [DOM Level 2 Traversal and Range]
.
| Returns | |
|---|---|
int |
|
startElement
public abstract short startElement (Element elementArg)
The parser will call this method after each Element start
tag has been scanned, but before the remainder of the
Element is processed. The intent is to allow the
element, including any children, to be efficiently skipped. Note that
only element nodes are passed to the startElement
function.
The element node passed to startElement for filtering
will include all of the Element's attributes, but none of the
children nodes. The Element may not yet be in place in the document
being constructed (it may not have a parent node.)
A startElement filter function may access or change
the attributes for the Element. Changing Namespace declarations will
have no effect on namespace resolution by the parser.
For efficiency, the Element node passed to the filter may not be
the same one as is actually placed in the tree if the node is
accepted. And the actual node (node object identity) may be reused
during the process of reading in and filtering a document.
| Parameters | |
|---|---|
elementArg |
Element: The newly encountered element. At the time this
method is called, the element is incomplete - it will have its
attributes, but no children. |
| Returns | |
|---|---|
short |
|