Class used to intercept various parsing events and use them to
populate a DOM document. Subclasses would typically know and use
backdoors into specific DOM implementations, used to implement
DTD-related functionality.
Note that if this ever throws a DOMException (runtime exception)
that will indicate a bug in the DOM (e.g. doesn't support something
per specification) or the parser (e.g. emitted an illegal name, or
accepted illegal input data).
canPopulateEntityRefs
public boolean canPopulateEntityRefs()
May be overridden by subclasses to return true, indicating
that entity reference nodes can be populated and then made
read-only.
characters
public void characters(ch[] ,
int start,
int length)
throws SAXException Receive notification of character data.
The Parser will call this method to report each chunk of
character data. SAX parsers may return all contiguous character
data in a single chunk, or they may split it into several
chunks; however, all of the characters in any single event
must come from the same external entity so that the Locator
provides useful information.
The application must not attempt to read from the array
outside of the specified range.
Individual characters may consist of more than one Java
char value. There are two important cases where this
happens, because characters can't be represented in just sixteen bits.
In one case, characters are represented in a
Surrogate Pair,
using two special Unicode values. Such characters are in the so-called
"Astral Planes", with a code point above U+FFFF. A second case involves
composite characters, such as a base character combining with one or
more accent characters.
Your code should not assume that algorithms using
char-at-a-time idioms will be working in character
units; in some cases they will split characters. This is relevant
wherever XML permits arbitrary characters, such as attribute values,
processing instruction data, and comments as well as in data reported
from this method. It's also generally relevant whenever Java code
manipulates internationalized text; the issue isn't unique to XML.
Note that some parsers will report whitespace in element
content using the
ignorableWhitespace
method rather than this one (validating parsers
must
do so).
- characters in interface ContentHandler
start - the start position in the arraylength - the number of characters to read from the array
SAXException - any SAX exception, possibly
wrapping another exception
ContentHandler.ignorableWhitespace(ch[],int,int), Locator
createText
protected Text createText(boolean isCDATA,
ch[] ,
int start,
int length) Subclasses may overrride this method to provide a more efficient
way to construct text nodes.
Typically, copying the text into a single character array will
be more efficient than doing that as well as allocating other
needed for a String, including an internal StringBuffer.
Those additional memory and CPU costs can be incurred later,
if ever needed.
Unfortunately the standard DOM factory APIs encourage those costs
to be incurred early.
endDocument
public void endDocument()
throws SAXException Receive notification of the end of a document.
There is an apparent contradiction between the
documentation for this method and the documentation for ErrorHandler.fatalError(SAXParseException). Until this ambiguity is
resolved in a future major release, clients should make no
assumptions about whether endDocument() will or will not be
invoked when the parser has reported a fatalError() or thrown
an exception.
The SAX parser will invoke this method only once, and it will
be the last method invoked during the parse. The parser shall
not invoke this method until it has either abandoned parsing
(because of an unrecoverable error) or reached the end of
input.
- endDocument in interface ContentHandler
SAXException - any SAX exception, possibly
wrapping another exception
ContentHandler.startDocument()
endElement
public void endElement(String uri,
String localName,
String qName)
throws SAXException Receive notification of the end of an element.
The SAX parser will invoke this method at the end of every
element in the XML document; there will be a corresponding
startElement event for every endElement
event (even when the element is empty).
For information on the names, see startElement.
- endElement in interface ContentHandler
uri - the Namespace URI, or the empty string if the
element has no Namespace URI or if Namespace
processing is not being performedlocalName - the local name (without prefix), or the
empty string if Namespace processing is not being
performedqName - the qualified XML name (with prefix), or the
empty string if qualified names are not available
SAXException - any SAX exception, possibly
wrapping another exception
getDocument
protected Document getDocument()
Returns the document under construction.
getTop
protected Node getTop()
Returns the current node being populated. This is usually
an Element or Document, but it might be an EntityReference
node if some implementation-specific code knows how to put
those into the result tree and later mark them as readonly.
ignorableWhitespace
public void ignorableWhitespace(ch[] ,
int start,
int length)
throws SAXException Receive notification of ignorable whitespace in element content.
Validating Parsers must use this method to report each chunk
of whitespace in element content (see the W3C XML 1.0
recommendation, section 2.10): non-validating parsers may also
use this method if they are capable of parsing and using
content models.
SAX parsers may return all contiguous whitespace in a single
chunk, or they may split it into several chunks; however, all of
the characters in any single event must come from the same
external entity, so that the Locator provides useful
information.
The application must not attempt to read from the array
outside of the specified range.
- ignorableWhitespace in interface ContentHandler
start - the start position in the arraylength - the number of characters to read from the array
SAXException - any SAX exception, possibly
wrapping another exception
ContentHandler.characters(ch[],int,int)
processingInstruction
public void processingInstruction(String target,
String data)
throws SAXException Receive notification of a processing instruction.
The Parser will invoke this method once for each processing
instruction found: note that processing instructions may occur
before or after the main document element.
A SAX parser must never report an XML declaration (XML 1.0,
section 2.8) or a text declaration (XML 1.0, section 4.3.1)
using this method.
Like
characters(), processing instruction
data may have characters that need more than one
char
value.
- processingInstruction in interface ContentHandler
target - the processing instruction targetdata - the processing instruction data, or null if
none was supplied. The data does not include any
whitespace separating it from the target
SAXException - any SAX exception, possibly
wrapping another exception
setDocumentLocator
public void setDocumentLocator(Locator locator)
Receive an object for locating the origin of SAX document events.
SAX parsers are strongly encouraged (though not absolutely
required) to supply a locator: if it does so, it must supply
the locator to the application by invoking this method before
invoking any of the other methods in the ContentHandler
interface.
The locator allows the application to determine the end
position of any document-related event, even if the parser is
not reporting an error. Typically, the application will
use this information for reporting its own errors (such as
character content that does not match an application's
business rules). The information returned by the locator
is probably not sufficient for use with a search engine.
Note that the locator will return correct information only
during the invocation SAX event callbacks after
startDocument returns and before
endDocument is called. The
application should not attempt to use it at any other time.
- setDocumentLocator in interface ContentHandler
locator - an object that can return the location of
any SAX document event
Locator
skippedEntity
public void skippedEntity(String name)
throws SAXException Receive notification of a skipped entity.
This is not called for entity references within markup constructs
such as element start tags or markup declarations. (The XML
recommendation requires reporting skipped external entities.
SAX also reports internal entity expansion/non-expansion, except
within markup constructs.)
The Parser will invoke this method each time the entity is
skipped. Non-validating processors may skip entities if they
have not seen the declarations (because, for example, the
entity was declared in an external DTD subset). All processors
may skip external entities, depending on the values of the
http://xml.org/sax/features/external-general-entities
and the
http://xml.org/sax/features/external-parameter-entities
properties.
- skippedEntity in interface ContentHandler
name - the name of the skipped entity. If it is a
parameter entity, the name will begin with '%', and if
it is the external DTD subset, it will be the string
"[dtd]"
SAXException - any SAX exception, possibly
wrapping another exception
startElement
public void startElement(String uri,
String localName,
String qName,
Attributes atts)
throws SAXException Receive notification of the beginning of an element.
The Parser will invoke this method at the beginning of every
element in the XML document; there will be a corresponding
endElement event for every startElement event
(even when the element is empty). All of the element's content will be
reported, in order, before the corresponding endElement
event.
This event allows up to three name components for each
element:
- the Namespace URI;
- the local name; and
- the qualified (prefixed) name.
Any or all of these may be provided, depending on the
values of the
http://xml.org/sax/features/namespaces
and the
http://xml.org/sax/features/namespace-prefixes
properties:
- the Namespace URI and local name are required when
the namespaces property is true (the default), and are
optional when the namespaces property is false (if one is
specified, both must be);
- the qualified name is required when the namespace-prefixes property
is true, and is optional when the namespace-prefixes property
is false (the default).
Note that the attribute list provided will contain only
attributes with explicit values (specified or defaulted):
#IMPLIED attributes will be omitted. The attribute list
will contain attributes used for Namespace declarations
(xmlns* attributes) only if the
http://xml.org/sax/features/namespace-prefixes
property is true (it is false by default, and support for a
true value is optional).
Like
characters(), attribute values may have
characters that need more than one
char value.
- startElement in interface ContentHandler
uri - the Namespace URI, or the empty string if the
element has no Namespace URI or if Namespace
processing is not being performedlocalName - the local name (without prefix), or the
empty string if Namespace processing is not being
performedqName - the qualified name (with prefix), or the
empty string if qualified names are not availableatts - the attributes attached to the element. If
there are no attributes, it shall be an empty
Attributes object. The value of this object after
startElement returns is undefined
SAXException - any SAX exception, possibly
wrapping another exception
ContentHandler.endElement(String,String,String), Attributes, AttributesImpl
startPrefixMapping
public void startPrefixMapping(String prefix,
String uri)
throws SAXException Begin the scope of a prefix-URI Namespace mapping.
The information from this event is not necessary for
normal Namespace processing: the SAX XML reader will
automatically replace prefixes for element and attribute
names when the
http://xml.org/sax/features/namespaces
feature is
true (the default).
There are cases, however, when applications need to
use prefixes in character data or in attribute values,
where they cannot safely be expanded automatically; the
start/endPrefixMapping event supplies the information
to the application to expand prefixes in those contexts
itself, if necessary.
Note that start/endPrefixMapping events are not
guaranteed to be properly nested relative to each other:
all startPrefixMapping events will occur immediately before the
corresponding
startElement event,
and all
endPrefixMapping
events will occur immediately after the corresponding
endElement event,
but their order is not otherwise
guaranteed.
There should never be start/endPrefixMapping events for the
"xml" prefix, since it is predeclared and immutable.
- startPrefixMapping in interface ContentHandler
prefix - the Namespace prefix being declared.
An empty string is used for the default element namespace,
which has no prefix.uri - the Namespace URI the prefix is mapped to
SAXException - the client may throw
an exception during processing
ContentHandler.endPrefixMapping(String), ContentHandler.startElement(String,String,String,Attributes)
xmlDecl
public void xmlDecl(String version,
String encoding,
boolean standalone,
String inputEncoding)
throws SAXException Reports the XML declaration.
- xmlDecl in interface ContentHandler2
version - the value of the version attribute in the XML
declarationencoding - the encoding specified in the XML declaration, if anystandalone - the standalone attribute from the XML declarationinputEncoding - the encoding of the XML input