public interface LSSerializer
LSSerializer
provides an API for serializing (writing) a DOM document out into XML. The XML data is written to a string or an output stream. Any changes or fixups made during the serialization affect only the serialized data. The Document
object and its children are never altered by the serialization operation. During serialization of XML data, namespace fixup is done as defined in [DOM Level 3 Core] , Appendix B. [DOM Level 2 Core] 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.
LSSerializer
accepts any node type for serialization. For nodes of type Document
or Entity
, well-formed XML will be created when possible (well-formedness is guaranteed if the document or entity comes from a parse operation and is unchanged since it was created). The serialized output for these node types is either as a XML document or an External XML Entity, respectively, and is acceptable input for an XML parser. For all other types of nodes the serialized form is implementation dependent.
Within a Document
, DocumentFragment
, or Entity
being serialized, Nodes
are processed as follows
Document
nodes are written, including the XML declaration (unless the parameter "xml-declaration" is set to false
) and a DTD subset, if one exists in the DOM. Writing a Document
node serializes the entire document. Entity
nodes, when written directly by LSSerializer.write
, outputs the entity expansion but no namespace fixup is done. The resulting output will be valid as an external entity. true
, EntityReference
nodes are serialized as an entity reference of the form " &entityName;
" in the output. Child nodes (the expansion) of the entity reference are ignored. If the parameter "entities" is set to false
, only the children of the entity reference are serialized. EntityReference
nodes with no children (no corresponding Entity
node or the corresponding Entity
nodes have no children) are always serialized. CDATAsections
containing content characters that cannot be represented in the specified output encoding are handled according to the "split-cdata-sections" parameter. If the parameter is set to true
, CDATAsections
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 parameter is set to false
, unrepresentable characters in a CDATAsection
are reported as "wf-invalid-character"
errors if the parameter "well-formed" is set to true
. 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. Note: The serialization of a Node
does not always generate a well-formed XML document, i.e. a LSParser
might throw 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 (>, ', and ") might not be used, except where needed (e.g. using > in cases such as ']]>'). Any characters that cannot be represented directly in the output character encoding are serialized as numeric character references (and since character encoding standards commonly use hexadecimal representations of characters, using the hexadecimal representation when serializing character references is encouraged).
To allow attribute values to contain both single and double quotes, the apostrophe or single-quote character (') may be represented as "'", and the double-quote character (") as """. New line characters and other characters that cannot be represented directly in attribute values in the output character encoding are 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 a DOMError
fatal error. An example would be serializing the element <LaCañada/> with encoding="us-ascii"
. This will result with a generation of a DOMError
"wf-invalid-character-in-node-name" (as proposed in "well-formed").
When requested by setting the parameter "normalize-characters" on LSSerializer
to true, character normalization is performed according to the definition of fully normalized characters included in appendix E of [XML 1.1] on all data to be serialized, both markup and character data. The character 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.
Implementations are required to support the encodings "UTF-8", "UTF-16", "UTF-16BE", and "UTF-16LE" to guarantee that data is serializable in all encodings that are required to be supported by all XML parsers. When the encoding is UTF-8, whether or not a byte order mark is serialized, or if the output is big-endian or little-endian, is implementation dependent. When the encoding is UTF-16, whether or not the output is big-endian or little-endian is implementation dependent, but a Byte Order Mark must be generated for non-character outputs, such as LSOutput.byteStream
or LSOutput.systemId
. If the Byte Order Mark is not generated, a "byte-order-mark-needed" warning is reported. When the encoding is UTF-16LE or UTF-16BE, the output is big-endian (UTF-16BE) or little-endian (UTF-16LE) and the Byte Order Mark is not be generated. In all cases, the encoding declaration, if generated, will correspond to the encoding used during the serialization (e.g. encoding="UTF-16"
will appear if UTF-16 was requested).
Namespaces are fixed up during serialization, the serialization process will verify that namespace declarations, namespace prefixes and the namespace URI associated with elements and attributes are consistent. If inconsistencies are found, the serialized form of the document will be altered to remove them. The method used for doing the namespace fixup while serializing a document is the algorithm defined in Appendix B.1, "Namespace normalization", of [DOM Level 3 Core] .
While serializing a document, the parameter "discard-default-content" controls whether or not non-specified data is serialized.
While serializing, errors and warnings are reported to the application through the error handler (LSSerializer.domConfig
's "error-handler" parameter). This specification does in no way try to define all possible errors and warnings that can occur while serializing a DOM node, but some common error and warning cases are defined. The types ( DOMError.type
) of errors and warnings defined by this specification are:
"no-output-specified" [fatal]
LSOutput
if no output is specified in the LSOutput
. "unbound-prefix-in-entity-reference" [fatal]
true
and an entity whose replacement text contains unbound namespace prefixes is referenced in a location where there are no bindings for the namespace prefixes. "unsupported-encoding" [fatal]
In addition to raising the defined errors and warnings, implementations are expected to raise implementation specific errors and warnings for any other error and warning cases such as IO errors (file not found, permission denied,...) and so on.
See also the Document Object Model (DOM) Level 3 Load and Save Specification.
Modifier and Type | Method | Description |
---|---|---|
DOMConfiguration |
getDomConfig() |
The DOMConfiguration object used by the LSSerializer when serializing a DOM node. |
LSSerializerFilter |
getFilter() |
When the application provides a filter, the serializer will call out to the filter before serializing each Node. |
String |
getNewLine() |
The end-of-line sequence of characters to be used in the XML being written out. |
void |
setFilter |
When the application provides a filter, the serializer will call out to the filter before serializing each Node. |
void |
setNewLine |
The end-of-line sequence of characters to be used in the XML being written out. |
boolean |
write |
Serialize the specified node as described above in the general description of the LSSerializer interface. |
String |
writeToString |
Serialize the specified node as described above in the general description of the LSSerializer interface. |
boolean |
writeToURI |
A convenience method that acts as if LSSerializer.write was called with a LSOutput with no encoding specified and LSOutput.systemId set to the uri argument. |
DOMConfiguration getDomConfig()
DOMConfiguration
object used by the LSSerializer
when serializing a DOM node. DOMConfiguration
objects for LSSerializer
adds, or modifies, the following parameters: "canonical-form"
true
true
will set the parameters "format-pretty-print", "discard-default-content", and "xml-declaration ", to false
. Setting one of those parameters to true
will set this parameter to false
. Serializing an XML 1.1 document when "canonical-form" is true
will generate a fatal error. false
"discard-default-content"
true
Attr.specified
attribute to decide what attributes should be discarded. Note that some implementations might use whatever information available to the implementation (i.e. XML schema, DTD, the Attr.specified
attribute, and so on) to determine what attributes and content to discard if this parameter is set to true
. false
"format-pretty-print"
true
false
"ignore-unknown-character-denormalizations"
true
"unknown-character-denormalization"
warning (instead of raising an error, if this parameter is not set) and ignore any possible denormalizations caused by these characters. false
"normalize-characters"
DOMConfiguration
in [DOM Level 3 Core] . Unlike in the Core, the default value for this parameter is true
. While DOM implementations are not required to support fully normalizing the characters in the document according to appendix E of [XML 1.1], this parameter must be activated by default if supported. "xml-declaration"
true
Document
, Element
, or Entity
node is serialized, the XML declaration, or text declaration, should be included. The version (Document.xmlVersion
if the document is a Level 3 document and the version is non-null, otherwise use the value "1.0"), and the output encoding (see LSSerializer.write
for details on how to find the output encoding) are specified in the serialized XML declaration. false
"xml-declaration-needed"
warning if this will cause problems (i.e. the serialized data is of an XML version other than [XML 1.0], or an encoding would be needed to be able to re-parse the serialized data). String getNewLine()
null
will reset its value to the default value. void setNewLine(String newLine)
null
will reset its value to the default value. LSSerializerFilter getFilter()
DOMConfiguration
parameters have been applied. For example, CDATA sections won't be passed to the filter if "cdata-sections" is set to false
.void setFilter(LSSerializerFilter filter)
DOMConfiguration
parameters have been applied. For example, CDATA sections won't be passed to the filter if "cdata-sections" is set to false
.boolean write(Node nodeArg, LSOutput destination) throws LSException
LSSerializer
interface. The output is written to the supplied LSOutput
. LSOutput
, the encoding is found by looking at the encoding information that is reachable through the LSOutput
and the item to be written (or its owner document) in this order: LSOutput.encoding
, Document.inputEncoding
, Document.xmlEncoding
. LSOutput
, a "no-output-specified" fatal error is raised. nodeArg
- The node to serialize.destination
- The destination for the serialized DOM.true
if node
was successfully serialized. Return false
in case the normal processing stopped but the implementation kept serializing the document; the result of the serialization being implementation dependent then.LSException
- SERIALIZE_ERR: Raised if the LSSerializer
was unable to serialize the node. DOM applications should attach a DOMErrorHandler
using the parameter "error-handler" if they wish to get details on the error.boolean writeToURI(Node nodeArg, String uri) throws LSException
LSSerializer.write
was called with a LSOutput
with no encoding specified and LSOutput.systemId
set to the uri
argument.nodeArg
- The node to serialize.uri
- The URI to write to.true
if node
was successfully serialized. Return false
in case the normal processing stopped but the implementation kept serializing the document; the result of the serialization being implementation dependent then.LSException
- SERIALIZE_ERR: Raised if the LSSerializer
was unable to serialize the node. DOM applications should attach a DOMErrorHandler
using the parameter "error-handler" if they wish to get details on the error.String writeToString(Node nodeArg) throws DOMException, LSException
LSSerializer
interface. The output is written to a DOMString
that is returned to the caller. The encoding used is the encoding of the DOMString
type, i.e. UTF-16. Note that no Byte Order Mark is generated in a DOMString
object.nodeArg
- The node to serialize.DOMException
- DOMSTRING_SIZE_ERR: Raised if the resulting string is too long to fit in a DOMString
.LSException
- SERIALIZE_ERR: Raised if the LSSerializer
was unable to serialize the node. DOM applications should attach a DOMErrorHandler
using the parameter "error-handler" if they wish to get details on the error.
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