SAX2 Standard Feature Flags
One of the essential characteristics of SAX2 is that it added
feature flags which can be used to examine and perhaps modify
parser modes, in particular modes such as validation.
Since features are identified by (absolute) URIs, anyone
can define such features.
Currently defined standard feature URIs have the prefix
http://xml.org/sax/features/ before an identifier such as
validation. Turn features on or off using
setFeature. Those standard identifiers are:
|external-general-entities||read/write||unspecified||Reports whether this parser processes external general entities; always true if validating.|
|external-parameter-entities||read/write||unspecified||Reports whether this parser processes external parameter entities; always true if validating.|
|is-standalone||(parsing) read-only, (not parsing) none||not applicable||May be examined only during a parse, after the startDocument() callback has been completed; read-only. The value is true if the document specified standalone="yes" in its XML declaration, and otherwise is false.|
|lexical-handler/parameter-entities||read/write||unspecified||A value of "true" indicates that the LexicalHandler will report the beginning and end of parameter entities.|
|namespaces||read/write||true||A value of "true" indicates namespace URIs and unprefixed local names for element and attribute names will be available.|
|namespace-prefixes||read/write||false||A value of "true" indicates that XML qualified names (with prefixes) and attributes (including xmlns* attributes) will be available.|
|resolve-dtd-uris||read/write||true|| A value of "true" indicates that system IDs in declarations will
be absolutized (relative to their base URIs) before reporting.
(That is the default behavior for all SAX2 XML parsers.)
A value of "false" indicates those IDs will not be absolutized;
parsers will provide the base URI from
This applies to system IDs passed in
|string-interning||read/write||unspecified||Has a value of "true" if all XML names (for elements, prefixes, attributes, entities, notations, and local names), as well as Namespace URIs, will have been interned using java.lang.String.intern. This supports fast testing of equality/inequality against string constants, rather than forcing slower calls to String.equals().|
|unicode-normalization-checking||read/write||false||Controls whether the parser reports Unicode normalization errors as described in section 2.13 and Appendix B of the XML 1.1 Recommendation. If true, Unicode normalization errors are reported using the ErrorHandler.error() callback. Such errors are not fatal in themselves (though, obviously, other Unicode-related encoding errors may be).|
|use-attributes2||read-only||not applicable||Returns "true" if the Attributes objects passed by this parser in ContentHandler.startElement() implement the org.xml.sax.ext.Attributes2 interface. That interface exposes additional DTD-related information, such as whether the attribute was specified in the source text rather than defaulted.|
|use-locator2||read-only||not applicable||Returns "true" if the Locator objects passed by this parser in ContentHandler.setDocumentLocator() implement the org.xml.sax.ext.Locator2 interface. That interface exposes additional entity information, such as the character encoding and XML version used.|
|use-entity-resolver2||read/write||true||Returns "true" if, when setEntityResolver is given an object implementing the org.xml.sax.ext.EntityResolver2 interface, those new methods will be used. Returns "false" to indicate that those methods will not be used.|
|validation||read/write||unspecified||Controls whether the parser is reporting all validity errors; if true, all external entities will be read.|
|xmlns-uris||read/write||false||Controls whether, when the namespace-prefixes feature is set, the parser treats namespace declaration attributes as being in the http://www.w3.org/2000/xmlns/ namespace. By default, SAX2 conforms to the original "Namespaces in XML" Recommendation, which explicitly states that such attributes are not in any namespace. Setting this optional flag to "true" makes the SAX2 events conform to a later backwards-incompatible revision of that recommendation, placing those attributes in a namespace.|
|xml-1.1||read-only||not applicable||Returns "true" if the parser supports both XML 1.1 and XML 1.0. Returns "false" if the parser supports only XML 1.0.|
Support for the default values of the namespaces and namespace-prefixes properties is required. Support for any other feature flags is entirely optional.
For default values not specified by SAX2, each XMLReader implementation specifies its default, or may choose not to expose the feature flag. Unless otherwise specified here, implementations may support changing current values of these standard feature flags, but not while parsing.
SAX2 Standard Handler and Property IDs
For parser interface characteristics that are described
as objects, a separate namespace is defined. The
objects in this namespace are again identified by URI, and
the standard property URIs have the prefix
http://xml.org/sax/properties/ before an identifier such as
dom-node. Manage those properties using
setProperty(). Those identifiers are:
|declaration-handler||Used to see most DTD declarations except those treated as lexical ("document element name is ...") or which are mandatory for all SAX parsers (DTDHandler). The Object must implement org.xml.sax.ext.DeclHandler.|
|document-xml-version||May be examined only during a parse, after the startDocument() callback has been completed; read-only. This property is a literal string describing the actual XML version of the document, such as "1.0" or "1.1".|
|dom-node||For "DOM Walker" style parsers, which ignore their parser.parse() parameters, this is used to specify the DOM (sub)tree being walked by the parser. The Object must implement the org.w3c.dom.Node interface.|
|lexical-handler||Used to see some syntax events that are essential in some applications: comments, CDATA delimiters, selected general entity inclusions, and the start and end of the DTD (and declaration of document element name). The Object must implement org.xml.sax.ext.LexicalHandler.|
|xml-string||Readable only during a parser callback, this exposes a TBS chunk of characters responsible for the current event.|
All of these standard properties are optional. XMLReader implementations are not required to support them.
- API Note:
- The SAX API, originally developed at the SAX Project, has been defined by Java SE since 1.4.
Interface Summary Interface Description AttributeList Deprecated.This interface has been replaced by the SAX2
Attributesinterface, which includes Namespace support.
AttributesInterface for a list of XML attributes. ContentHandlerReceive notification of the logical content of a document. DocumentHandler Deprecated.This interface has been replaced by the SAX2
ContentHandlerinterface, which includes Namespace support.
DTDHandlerReceive notification of basic DTD-related events. EntityResolverBasic interface for resolving entities. ErrorHandlerBasic interface for SAX error handlers. LocatorInterface for associating a SAX event with a document location. Parser Deprecated.This interface has been replaced by the SAX2
XMLReaderinterface, which includes Namespace support.
XMLFilterInterface for an XML filter. XMLReaderInterface for reading an XML document using callbacks.
Exception Summary Exception Description SAXExceptionEncapsulate a general SAX error or warning. SAXNotRecognizedExceptionException class for an unrecognized identifier. SAXNotSupportedExceptionException class for an unsupported operation. SAXParseExceptionEncapsulate an XML parse error or warning.