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DOM Level 3 WD Experimental: The DOM Level 3 specification is at the stage of Working Draft, which represents work in progress and thus may be updated, replaced, or obsoleted by other documents at any time.
DOMWriter
provides an API for serializing (writing) a DOM
document out in an XML document. The XML data is written to an output
stream, the type of which depends on the specific language bindings in
use.
During serialization of XML data, namespace fixup is done when possible
as defined in , Appendix B. allows empty strings as a real namespace
URI. If the namespaceURI
of a Node
is empty
string, the serialization will treat them as null
, ignoring
the prefix if any. should the remark on DOM Level 2 namespace URI
included in the namespace algorithm in Core instead?
DOMWriter
accepts any node type for serialization. For
nodes of type Document
or Entity
, well formed
XML will be created if possible. The serialized output for these node
types is either as a Document or an External Entity, respectively, and is
acceptable input for an XML parser. For all other types of nodes the
serialized form is not specified, but should be something useful to a
human for debugging or diagnostic purposes. Note: rigorously designing an
external (source) form for stand-alone node types that don't already have
one defined in seems a bit much to take on here.
Within a Document, DocumentFragment, or Entity being serialized, Nodes
are processed as follows Documents are written including an XML
declaration and a DTD subset, if one exists in the DOM. Writing a
document node serializes the entire document. Entity nodes, when written
directly by writeNode
defined in the DOMWriter
interface, output the entity expansion but no namespace fixup is done.
The resulting output will be valid as an external entity. Entity
reference nodes are serialized as an entity reference of the form "
&entityName;
" in the output. Child nodes (the expansion)
of the entity reference are ignored. CDATA sections containing content
characters that can not be represented in the specified output encoding
are handled according to the "split-cdata-sections" feature.If the
feature is true
, CDATA sections are split, and the
unrepresentable characters are serialized as numeric character references
in ordinary content. The exact position and number of splits is not
specified. If the feature is false
, unrepresentable
characters in a CDATA section are reported as errors. The error is not
recoverable - there is no mechanism for supplying alternative characters
and continuing with the serialization. DocumentFragment nodes are
serialized by serializing the children of the document fragment in the
order they appear in the document fragment. All other node types
(Element, Text, etc.) are serialized to their corresponding XML source
form. The serialization of a DOM Node does not always generate a
well-formed XML document, i.e. a DOMBuilder
might through
fatal errors when parsing the resulting serialization.
Within the character data of a document (outside of markup), any characters that cannot be represented directly are replaced with character references. Occurrences of '<' and '&' are replaced by the predefined entities < and &. The other predefined entities (>, &apos, etc.) are not used; these characters can be included directly. Any character that can not be represented directly in the output character encoding is serialized as a numeric character reference.
Attributes not containing quotes are serialized in quotes. Attributes containing quotes but no apostrophes are serialized in apostrophes (single quotes). Attributes containing both forms of quotes are serialized in quotes, with quotes within the value represented by the predefined entity ". Any character that can not be represented directly in the output character encoding is serialized as a numeric character reference.
Within markup, but outside of attributes, any occurrence of a character that cannot be represented in the output character encoding is reported as an error. An example would be serializing the element <LaCa?ada/> with the encoding="us-ascii".
When requested by setting the normalize-characters
feature
on DOMWriter
, all data to be serialized, both markup and
character data, is W3C Text normalized according to the rules defined in
. The W3C Text normalization process affects only the data as it is being
written; it does not alter the DOM's view of the document after
serialization has completed.
Namespaces are fixed up during serialization, the serialization process will verify that namespace declarations, namespace prefixes and the namespace URIs associated with Elements and Attributes are consistent. If inconsistencies are found, the serialized form of the document will be altered to remove them. The algorithm used for doing the namespace fixup while serializing a document is a combination of the algorithms used for lookupNamespaceURI and lookupNamespacePrefix . previous paragraph to be defined closer here.
Any changes made affect only the namespace prefixes and declarations appearing in the serialized data. The DOM's view of the document is not altered by the serialization operation, and does not reflect any changes made to namespace declarations or prefixes in the serialized output.
While serializing a document the serializer will write out
non-specified values (such as attributes whose specified
is
false
) if the discard-default-content
feature
is set to true
. If the discard-default-content
flag is set to false
and a schema is used for validation,
the schema will be also used to determine if a value is specified or not.
If no schema is used, the specified
flag on attribute nodes
is used to determine if attribute values should be written out.
Ref to Core spec (1.1.9, XML namespaces, 5th paragraph) entity ref
description about warning about unbound entity refs. Entity refs are
always serialized as &foo;
, also mention this in the
load part of this spec.
DOMWriter
s have a number of named features that can be
queried or set. The name of DOMWriter
features must be valid
XML names. Implementation specific features (extensions) should choose an
implementation dependent prefix to avoid name collisions.
Here is a list of features that must be recognized by all
implementations. Using these features does affect the Node
being serialized, only its serialized form is affected.
"discard-default-content"
Document.setNormalizationFeature
in . "canonical-form"
true
"format-pretty-print"
to false. false
"entities"
Document.setNormalizationFeature
in . "format-pretty-print"
true
false
"namespaces"
Document.setNormalizationFeature
in . "normalize-characters"
Document.setNormalizationFeature
in . Unlike in
the Core, the default value for this feature is true
. "split-cdata-sections"
Document.setNormalizationFeature
in . "validate"
Document.setNormalizationFeature
in . "unknown-characters"
true
false
"whitespace-in-element-content"
Document.setNormalizationFeature
in . See also the Document Object Model (DOM) Level 3 Load and Save Specification.
Method Summary | |
boolean |
canSetFeature(java.lang.String name,
boolean state)
Query whether setting a feature to a specific value is supported. |
java.lang.String |
getEncoding()
The character encoding in which the output will be written. |
org.apache.xerces.dom3.DOMErrorHandler |
getErrorHandler()
The error handler that will receive error notifications during serialization. |
boolean |
getFeature(java.lang.String name)
Look up the value of a feature. |
DOMWriterFilter |
getFilter()
When the application provides a filter, the serializer will call out to the filter before serializing each Node. |
java.lang.String |
getNewLine()
The end-of-line sequence of characters to be used in the XML being written out. |
void |
setEncoding(java.lang.String encoding)
The character encoding in which the output will be written. |
void |
setErrorHandler(org.apache.xerces.dom3.DOMErrorHandler errorHandler)
The error handler that will receive error notifications during serialization. |
void |
setFeature(java.lang.String name,
boolean state)
Set the state of a feature. |
void |
setFilter(DOMWriterFilter filter)
When the application provides a filter, the serializer will call out to the filter before serializing each Node. |
void |
setNewLine(java.lang.String newLine)
The end-of-line sequence of characters to be used in the XML being written out. |
boolean |
writeNode(java.io.OutputStream destination,
Node wnode)
Write out the specified node as described above in the description of DOMWriter . |
java.lang.String |
writeToString(Node wnode)
Serialize the specified node as described above in the description of DOMWriter . |
Method Detail |
public void setFeature(java.lang.String name, boolean state) throws DOMException
DOMWriter
to recognize a feature
name but to be unable to set its value.
name
- The feature name.state
- The requested state of the feature (true
or
false
).
DOMException
- NOT_SUPPORTED_ERR: Raised when the DOMWriter
recognizes
the feature name but cannot set the requested value.
DOMWriter
does not
recognize the feature name.public boolean canSetFeature(java.lang.String name, boolean state)
name
- The feature name, which is a DOM has-feature style string.state
- The requested state of the feature (true
or
false
).
true
if the feature could be successfully set to
the specified value, or false
if the feature is not
recognized or the requested value is not supported. The value of
the feature itself is not changed.public boolean getFeature(java.lang.String name) throws DOMException
name
- The feature name, which is a string with DOM has-feature
syntax.
true
or
false
).
DOMException
- NOT_FOUND_ERR: Raised when the DOMWriter
does not
recognize the feature name.public java.lang.String getEncoding()
null
or empty, but the item to be
written, or the owner document of the item, specifies an encoding
(i.e. the "actualEncoding" from the document) specified encoding,
that value will be used.If neither of the above provides an encoding
name, a default encoding of "UTF-8" will be used.
null
.
public void setEncoding(java.lang.String encoding)
null
or empty, but the item to be
written, or the owner document of the item, specifies an encoding
(i.e. the "actualEncoding" from the document) specified encoding,
that value will be used.If neither of the above provides an encoding
name, a default encoding of "UTF-8" will be used.
null
.
public java.lang.String getNewLine()
null
null
.
public void setNewLine(java.lang.String newLine)
null
null
.
public DOMWriterFilter getFilter()
public void setFilter(DOMWriterFilter filter)
public org.apache.xerces.dom3.DOMErrorHandler getErrorHandler()
public void setErrorHandler(org.apache.xerces.dom3.DOMErrorHandler errorHandler)
public boolean writeNode(java.io.OutputStream destination, Node wnode)
DOMWriter
. Writing a Document or Entity node produces a
serialized form that is well formed XML, when possible (Entity nodes
might not always be well formed XML in themselves). Writing other
node types produces a fragment of text in a form that is not fully
defined by this document, but that should be useful to a human for
debugging or diagnostic purposes.
destination
- The destination for the data to be written.wnode
- The Document
or Entity
node to
be written. For other node types, something sensible should be
written, but the exact serialized form is not specified.
true
if node
was
successfully serialized and false
in case a failure
occured and the failure wasn't canceled by the error handler.public java.lang.String writeToString(Node wnode) throws DOMException
DOMWriter
. The result of serializing the node is
returned as a DOMString (this method completely ignores all the
encoding information available). Writing a Document or Entity node
produces a serialized form that is well formed XML. Writing other
node types produces a fragment of text in a form that is not fully
defined by this document, but that should be useful to a human for
debugging or diagnostic purposes.
wnode
- The node to be written.
null
in case a
failure occured and the failure wasn't canceled by the error
handler.
DOMException
- DOMSTRING_SIZE_ERR: Raised if the resulting string is too long to
fit in a DOMString
.
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