nu.xom
public class Serializer extends Object
Outputs a Document
object in a specific encoding using
various options for controlling white space, normalization,
indenting, line breaking, and base URIs. However, in general these
options do affect the document's infoset. In particular, if you set
either the maximum line length or the indent size to a positive
value, then the serializer will not respect input white space. It
may trim leading and trailing space, condense runs of white
space to a single space, convert carriage returns and linefeeds
to spaces, add extra space where none was present before,
and otherwise muck with the document's white space.
The defaults, however, preserve all significant white space
including ignorable white space and boundary white space.
Version: 1.2d1
Constructor Summary | |
---|---|
Serializer(OutputStream out) Create a new serializer that uses the UTF-8 encoding. | |
Serializer(OutputStream out, String encoding) Create a new serializer that uses the specified encoding. |
Method Summary | |
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protected void | breakLine() Writes the current line break string onto the underlying output stream and indents as specified by the current level and the indent property. |
void | flush() Flushes the data onto the output stream. |
protected int | getColumnNumber() Returns the current column number of the output stream. |
String | getEncoding() Returns the name of the character encoding used by this serializer. |
int | getIndent() Returns the number of spaces this serializer indents. |
String | getLineSeparator() Returns the string used as a line separator. |
int | getMaxLength() Returns the preferred maximum line length. |
boolean | getPreserveBaseURI()
Returns true if this serializer preserves the original
base URIs by inserting extra |
boolean | getUnicodeNormalizationFormC() Indicates whether serialization will perform Unicode normalization on all data using normalization form C (NFC). |
void | setIndent(int indent) Sets the number of additional spaces to add to each successive level in the hierarchy. |
void | setLineSeparator(String lineSeparator) Sets the line separator. |
void | setMaxLength(int maxLength) Sets the suggested maximum line length for this serializer. |
void | setOutputStream(OutputStream out) Flushes the previous output stream and redirects further output to the new output stream. |
void | setPreserveBaseURI(boolean preserve)
Determines whether this serializer inserts
extra |
void | setUnicodeNormalizationFormC(boolean normalize) If true, this property indicates serialization will perform Unicode normalization on all data using normalization form C (NFC). |
void | write(Document doc) Serializes a document onto the output stream using the current options. |
protected void | write(Element element) Serializes an element onto the output stream using the current options. |
protected void | write(Attribute attribute)
Writes an attribute in the form
|
protected void | write(Comment comment) Writes a comment onto the output stream using the current options. |
protected void | write(ProcessingInstruction instruction) Writes a processing instruction onto the output stream using the current options. |
protected void | write(Text text)
Writes a |
protected void | write(DocType doctype)
Writes a |
protected void | writeAttributes(Element element) Writes all the attributes of the specified element onto the output stream, one at a time, separated by white space. |
protected void | writeAttributeValue(String value) Writes a string onto the underlying output stream. |
protected void | writeChild(Node node) Writes a child node onto the output stream using the current options. |
protected void | writeEmptyElementTag(Element element) Writes an empty-element tag for the element including all its namespace declarations and attributes. |
protected void | writeEndTag(Element element)
Writes the end-tag for an element in the form
|
protected void | writeEscaped(String text) Writes a string onto the underlying output stream. |
protected void | writeNamespaceDeclaration(String prefix, String uri)
Writes a namespace declaration in the form
|
protected void | writeNamespaceDeclarations(Element element) Writes all the namespace declaration attributes of the specified element onto the output stream, one at a time, separated by white space. |
protected void | writeRaw(String text) Writes a string onto the underlying output stream. without escaping any characters. |
protected void | writeStartTag(Element element) Writes the start-tag for the element including all its namespace declarations and attributes. |
protected void | writeXMLDeclaration() Writes the XML declaration onto the output stream, followed by a line break. |
Create a new serializer that uses the UTF-8 encoding.
Parameters: out the output stream to write the document on
Throws: NullPointerException if out
is null
Create a new serializer that uses the specified encoding.
The encoding must be recognized by the Java virtual machine. If
you attempt to use an encoding that the local Java virtual
machine does not support, the constructor will throw an
UnsupportedEncodingException
.
Currently the following encodings are recognized by XOM:
You can use encodings not in this list if the virtual machine supports them. However, they may be significantly slower than the encodings in this list.
I've noticed Java has significant bugs in its handling of some of these encodings. In some cases such as 0x80 in Big5, XOM will escape a character that should not need to be escaped because Java can't output that character in the specified encoding, even though the output character set does contain it. :-(
Parameters: out the output stream to write the document on encoding the character encoding for the serialization
Throws: NullPointerException if out
or encoding
is null UnsupportedEncodingException if the VM does not
support the requested encoding
Writes the current line break string onto the underlying output stream and indents as specified by the current level and the indent property.
Throws: IOException if the underlying output stream encounters an I/O error
Flushes the data onto the output stream. It is not enough to flush the output stream. You must flush the serializer object itself because it uses some internal buffering. The serializer will flush the underlying output stream.
Throws: IOException if the underlying output stream encounters an I/O error
Returns the current column number of the output stream. This method useful for subclasses that implement their own pretty printing strategies by inserting white space and line breaks at appropriate points.
Columns are counted based on Unicode characters, not Java chars. A surrogate pair counts as one character in this context, not two. However, a character followed by a combining character (e.g. e followed by combining accent acute) counts as two characters. This latter choice (treating combining characters like regular characters) is under review, and may change in the future if it's not too big a performance hit.
Returns: the current column number
Returns the name of the character encoding used by this serializer.
Returns: the encoding used for the output document
Returns the number of spaces this serializer indents.
Returns: the number of spaces this serializer indents each successive level beyond the previous one
Returns the string used as a line separator.
This is always "\n"
, "\r"
,
or "\r\n"
.
Returns: the line separator
Returns the preferred maximum line length.
Returns: the preferred maximum line length.
Returns true if this serializer preserves the original
base URIs by inserting extra xml:base
attributes.
Returns: true if this Serializer
inserts
extra xml:base
attributes to attempt to
preserve base URI information from the document.
Indicates whether serialization will perform Unicode normalization on all data using normalization form C (NFC). The default is false; do not normalize.
Returns: true if this serializer performs Unicode normalization; false if it doesn't
Sets the number of additional spaces to add to each successive level in the hierarchy. Use 0 for no extra indenting. The maximum indentation is in limited to approximately half the maximum line length. The serializer will not indent further than that no matter how many levels deep the hierarchy is.
When this variable is set to a value greater than 0, the serializer does not preserve white space. Spaces, tabs, carriage returns, and line feeds can all be interchanged at the serializer's discretion, and additional white space may be added before and after tags. Carriage returns, line feeds, and tabs will not be escaped with numeric character references.
Inside elements with an xml:space="preserve"
attribute, white space is preserved and no indenting
takes place, regardless of the setting of the indent
property, unless, of course, an
xml:space="default"
attribute overrides the
xml:space="preserve"
attribute.
The default value for indent is 0; that is, the default is not to add or subtract any white space from the source document.
Parameters: indent the number of spaces to indent each successive level of the hierarchy
Throws: IllegalArgumentException if indent is less than zero
Sets the line separator. This can only be one of the
three strings "\n"
, "\r"
,
or "\r\n"
. All other values are forbidden.
If this method is invoked, then
line separators in the character data will be changed to this
string. Line separators in attribute values will be changed
to the hexadecimal numeric character references corresponding
to this string.
The default line separator is "\r\n"
. However,
line separators in character data and attribute values are not
changed to this string, unless this method is called first.
Parameters: lineSeparator the line separator to set
Throws: IllegalArgumentException if you attempt to use any line
separator other than "\n"
, "\r"
,
or "\r\n"
.
Sets the suggested maximum line length for this serializer. Setting this to 0 indicates that no automatic wrapping is to be performed. When a line approaches this length, the serializer begins looking for opportunities to break the line. Generally it will break on any ASCII white space character (tab, carriage return, linefeed, and space). In some circumstances the serializer may not be able to break the line before the maximum length is reached. For instance, if an element name is longer than the maximum line length the only way to correctly serialize it is to exceed the maximum line length. In this case, the serializer will exceed the maximum line length.
The default value for maximum line length is 0, which is interpreted as no maximum line length. Setting this to a negative value just sets it to 0.
When this variable is set to a value greater than 0, the serializer does not preserve white space. Spaces, tabs, carriage returns, and line feeds can all be interchanged at the serializer's discretion. Carriage returns, line feeds, and tabs will not be escaped with numeric character references.
Inside elements with an xml:space="preserve"
attribute, the maximum line length is not enforced,
regardless of the setting of the this property, unless,
of course, an xml:space="default"
attribute
overrides the xml:space="preserve"
attribute.
Parameters: maxLength the preferred maximum line length
Flushes the previous output stream and redirects further output to the new output stream.
Parameters: out the output stream to write the document on
Throws: NullPointerException if out
is null IOException if the previous output stream
encounters an I/O error when flushed
Determines whether this serializer inserts
extra xml:base
attributes to attempt to
preserve base URI information from the document.
The default is false, do not preserve base URI information.
xml:base
attributes that have been explicitly
added to an element are always output. This property only
determines whether or not extra xml:base
attributes are added.
Parameters: preserve true if xml:base
attributes should be added as necessary
to preserve base URI information
If true, this property indicates serialization will perform Unicode normalization on all data using normalization form C (NFC). Performing Unicode normalization may change the document's infoset. The default is false; do not normalize. This version is based on Unicode 4.0.
This feature has not yet been benchmarked or optimized. It may result in substantially slower code.
If all your data is in the first 256 code points of Unicode (i.e. the ISO-8859-1, Latin-1 character set), then it's already in normalization form C and normalizing won't change anything.
Parameters: normalize true if normalization is performed; false if it isn't
Serializes a document onto the output stream using the current options.
Parameters: doc the Document
to serialize
Throws: IOException if the underlying output stream
encounters an I/O error NullPointerException if doc
is null UnavailableCharacterException if the document contains
an unescapable character (e.g. in an element name) that is
not available in the current encoding
Serializes an element onto the output stream using the current options. The result is guaranteed to be well-formed.
If the element is empty, this method invokes
writeEmptyElementTag
. If the element is not
empty, then:
writeStartTag
.writeChild
in order.writeEndTag
.It may break lines or add white space if the serializer has been configured to indent or use a maximum line length.
Parameters: element the Element
to serialize
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the element name contains a character that is not available in the current encoding
Writes an attribute in the form
name="value"
.
Characters in the attribute value are escaped as necessary.
Parameters: attribute the Attribute
to write
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the attribute name contains a character that is not available in the current encoding
Writes a comment onto the output stream using the current options. Since character and entity references are not resolved in comments, comments can only be serialized when all characters they contain are available in the current encoding.
Parameters: comment the Comment
to serialize
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the comment contains a character that is not available in the current encoding
Writes a processing instruction onto the output stream using the current options. Since character and entity references are not resolved in processing instructions, processing instructions can only be serialized when all characters they contain are available in the current encoding.
Parameters: instruction the ProcessingInstruction
to serialize
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the comment contains a character that is not available in the current encoding
Writes a Text
object
onto the output stream using the current options.
Reserved characters such as <, > and "
are escaped using the standard entity references
such as <
, >
,
and "
.
Characters which cannot be encoded in the current character set (for example, Ω in ISO-8859-1) are encoded using character references.
Parameters: text the Text
to serialize
Throws: IOException if the underlying output stream encounters an I/O error
Writes a DocType
object
onto the output stream using the current options.
Parameters: doctype the document type declaration to serialize
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the document type declaration contains a character that is not available in the current encoding
Writes all the attributes of the specified
element onto the output stream, one at a time, separated
by white space. If preserveBaseURI is true, and it is
necessary to add an xml:base
attribute
to the element in order to preserve the base URI, then
that attribute is also written here.
Each individual attribute is written by invoking
write(Attribute)
.
Parameters: element the Element
whose attributes are
written
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the name of any of the element's attributes contains a character that is not available in the current encoding
Writes a string onto the underlying output stream.
Non-ASCII characters that are not available in the
current character set are escaped using hexadecimal numeric
character references. Carriage returns, line feeds, and tabs
are also escaped using hexadecimal numeric character
references in order to ensure their preservation on a round
trip. The four reserved characters <, >, &,
and " are escaped using the standard entity references
<
, >
,
&
, and "
.
The single quote is not escaped.
Parameters: value the attribute value to serialize
Throws: IOException if the underlying output stream encounters an I/O error
Writes a child node onto the output stream using the
current options. It is invoked when walking the tree to
serialize the entire document. It is not called, and indeed
should not be called, for either the Document
node or for attributes.
Parameters: node the Node
to serialize
Throws: IOException if the underlying output stream
encounters an I/O error XMLException if an Attribute
, a
Document
, or Namespace
is passed to this method
Writes an empty-element tag for the element including all its namespace declarations and attributes.
The writeAttributes
method is called to write
all the non-namespace-declaration attributes.
The writeNamespaceDeclarations
method
is called to write all the namespace declaration attributes.
If subclasses don't wish empty-element tags to be used,
they can override this method to simply invoke
writeStartTag
followed by
writeEndTag
.
Parameters: element the element whose empty-element tag is written
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the name of the element or the name of any of its attributes contains a character that is not available in the current encoding
Writes the end-tag for an element in the form
</name>
.
Parameters: element the element whose end-tag is written
Throws: IOException if the underlying output stream encounters an I/O error
Writes a string onto the underlying output stream.
Non-ASCII characters that are not available in the
current character set are encoded with numeric character
references. The three reserved characters <, >, and &
are escaped using the standard entity references
<
, >
,
and &
.
Double and single quotes are not escaped.
Parameters: text the parsed character data to serialize
Throws: IOException if the underlying output stream encounters an I/O error
Writes a namespace declaration in the form
xmlns:prefix="uri"
or
xmlns="uri"
. It does not write
the spaces on either side of the namespace declaration.
These are written by writeNamespaceDeclarations
.
Parameters: prefix the namespace prefix; the empty string for the default namespace uri the namespace URI
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the namespace prefix contains a character that is not available in the current encoding
Writes all the namespace declaration
attributes of the specified element onto the output stream,
one at a time, separated by white space. Each individual
declaration is written by invoking
writeNamespaceDeclaration
.
Parameters: element the Element
whose namespace
declarations are written
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if any of the element's namespace prefixes contains a character that is not available in the current encoding
Writes a string onto the underlying output stream.
without escaping any characters.
Non-ASCII characters that are not available in the
current character set cause an IOException
.
Parameters: text the String
to serialize
Throws: IOException if the underlying output stream
encounters an I/O error or text
contains
characters not available in the current character set
Writes the start-tag for the element including all its namespace declarations and attributes.
The writeAttributes
method is called to write
all the non-namespace-declaration attributes.
The writeNamespaceDeclarations
method
is called to write all the namespace declaration attributes.
Parameters: element the element whose start-tag is written
Throws: IOException if the underlying output stream encounters an I/O error UnavailableCharacterException if the name of the element or the name of any of its attributes contains a character that is not available in the current encoding
Writes the XML declaration onto the output stream, followed by a line break.
Throws: IOException if the underlying output stream encounters an I/O error