Factory that creates Schema
objects. Entry-point to
the validation API.
SchemaFactory
is a schema compiler. It reads external
representations of schemas and prepares them for validation.
The SchemaFactory
class is not thread-safe. In other words,
it is the application's responsibility to ensure that at most
one thread is using a SchemaFactory
object at any
given moment. Implementations are encouraged to mark methods
as synchronized to protect themselves from broken clients.
SchemaFactory
is not re-entrant. While one of the
newSchema
methods is being invoked, applications
may not attempt to recursively invoke the newSchema
method,
even from the same thread.
Schema Language
This spec uses a namespace URI to designate a schema language. The following table shows the values defined by this specification.
To be compliant with the spec, the implementation is only required to support W3C XML Schema 1.0. However, if it chooses to support other schema languages listed here, it must conform to the relevant behaviors described in this spec.
Schema languages not listed here are expected to
introduce their own URIs to represent themselves.
The SchemaFactory
class is capable of locating other
implementations for other schema languages at run-time.
Note that because the XML DTD is strongly tied to the parsing process and has a significant effect on the parsing process, it is impossible to define the DTD validation as a process independent from parsing. For this reason, this specification does not define the semantics for the XML DTD. This doesn't prohibit implementers from implementing it in a way they see fit, but users are warned that any DTD validation implemented on this interface necessarily deviate from the XML DTD semantics as defined in the XML 1.0.
value | language |
---|---|
XMLConstants.W3C_XML_SCHEMA_NS_URI ("http://www.w3.org/2001/XMLSchema ") |
W3C XML Schema 1.0 |
XMLConstants.RELAXNG_NS_URI ("http://relaxng.org/ns/structure/1.0 ") |
RELAX NG 1.0 |
Protected Constructor Summary
SchemaFactory()
Constructor for derived classes. |
Public Method Summary
abstract ErrorHandler |
getErrorHandler()
Gets the current
ErrorHandler set to this SchemaFactory . |
boolean | |
Object | |
abstract LSResourceResolver |
getResourceResolver()
Gets the current
LSResourceResolver set to this SchemaFactory . |
abstract boolean |
isSchemaLanguageSupported(String schemaLanguage)
Is specified schema supported by this |
static SchemaFactory |
newInstance(String schemaLanguage, String factoryClassName, ClassLoader classLoader)
Returns an instance of the named implementation of
SchemaFactory . |
static SchemaFactory |
newInstance(String schemaLanguage)
Lookup an implementation of the |
Schema | |
Schema | |
abstract Schema | |
abstract Schema | |
Schema | |
abstract void |
setErrorHandler(ErrorHandler errorHandler)
Sets the
ErrorHandler to receive errors encountered
during the newSchema method invocation. |
void | |
void | |
abstract void |
setResourceResolver(LSResourceResolver resourceResolver)
Sets the
LSResourceResolver to customize
resource resolution when parsing schemas. |
Inherited Method Summary
Protected Constructors
protected SchemaFactory ()
Constructor for derived classes.
The constructor does nothing.
Derived classes must create SchemaFactory
objects that have
null
ErrorHandler
and
null
LSResourceResolver
.
Public Methods
public abstract ErrorHandler getErrorHandler ()
Gets the current ErrorHandler
set to this SchemaFactory
.
Returns
- This method returns the object that was last set through
the
setErrorHandler(ErrorHandler)
method, or null if that method has never been called since thisSchemaFactory
has created.
See Also
public boolean getFeature (String name)
Look up the value of a feature flag.
The feature name is any fully-qualified URI. It is
possible for a SchemaFactory
to recognize a feature name but
temporarily be unable to return its value.
Implementers are free (and encouraged) to invent their own features, using names built on their own URIs.
Parameters
name | The feature name, which is a non-null fully-qualified URI. |
---|
Returns
- The current value of the feature (true or false).
Throws
SAXNotRecognizedException | If the feature value can't be assigned or retrieved. |
---|---|
SAXNotSupportedException | When the
SchemaFactory recognizes the feature name but
cannot determine its value at this time. |
NullPointerException | if the name parameter is null. |
See Also
public Object getProperty (String name)
Look up the value of a property.
The property name is any fully-qualified URI. It is
possible for a SchemaFactory
to recognize a property name but
temporarily be unable to return its value.
SchemaFactory
s are not required to recognize any specific
property names.
Implementers are free (and encouraged) to invent their own properties, using names built on their own URIs.
Parameters
name | The property name, which is a non-null fully-qualified URI. |
---|
Returns
- The current value of the property.
Throws
SAXNotRecognizedException | If the property value can't be assigned or retrieved. |
---|---|
SAXNotSupportedException | When the XMLReader recognizes the property name but cannot determine its value at this time. |
NullPointerException | if the name parameter is null. |
See Also
public abstract LSResourceResolver getResourceResolver ()
Gets the current LSResourceResolver
set to this SchemaFactory
.
Returns
- This method returns the object that was last set through
the
setResourceResolver(LSResourceResolver)
method, or null if that method has never been called since thisSchemaFactory
has created.
See Also
public abstract boolean isSchemaLanguageSupported (String schemaLanguage)
Is specified schema supported by this SchemaFactory
?
Parameters
schemaLanguage | Specifies the schema language which the returned SchemaFactory will understand.
schemaLanguage must specify a valid schema language. |
---|
Returns
true
ifSchemaFactory
supportsschemaLanguage
, elsefalse
.
Throws
NullPointerException | If schemaLanguage is null . |
---|---|
IllegalArgumentException | If schemaLanguage.length() == 0
or schemaLanguage does not specify a valid schema language.
|
public static SchemaFactory newInstance (String schemaLanguage, String factoryClassName, ClassLoader classLoader)
Returns an instance of the named implementation of SchemaFactory
.
Parameters
schemaLanguage | |
---|---|
factoryClassName | |
classLoader |
Throws
IllegalArgumentException | if factoryClassName is not available, cannot be
instantiated, or doesn't support schemaLanguage . |
---|
public static SchemaFactory newInstance (String schemaLanguage)
Lookup an implementation of the SchemaFactory
that supports the specified
schema language and return it.
To find a SchemaFactory
object for a given schema language,
this method looks the following places in the following order
where "the class loader" refers to the context class loader:
-
If the system property
"javax.xml.validation.SchemaFactory:schemaLanguage"
is present (where schemaLanguage is the parameter to this method), then its value is read as a class name. The method will try to create a new instance of this class by using the class loader, and returns it if it is successfully created. -
$java.home/lib/jaxp.properties
is read and the value associated with the key being the system property above is looked for. If present, the value is processed just like above. -
The class loader is asked for service provider provider-configuration files matching
javax.xml.validation.SchemaFactory
in the resource directory META-INF/services. See the JAR File Specification for file format and parsing rules. Each potential service provider is required to implement the method: The first service provider found in class loader order that supports the specified schema language is returned.isSchemaLanguageSupported(String)
-
Platform default
SchemaFactory
is located in a implementation specific way. There must be a platform defaultSchemaFactory
for W3C XML Schema.
If everything fails, IllegalArgumentException
will be thrown.
Tip for Trouble-shooting:
See Properties.load(java.io.InputStream)
for
exactly how a property file is parsed. In particular, colons ':'
need to be escaped in a property file, so make sure schema language
URIs are properly escaped in it. For example:
http\://www.w3.org/2001/XMLSchema=org.acme.foo.XSSchemaFactory
Parameters
schemaLanguage | Specifies the schema language which the returned SchemaFactory will understand. See the list of available schema languages for the possible values. |
---|
Returns
- New instance of a
SchemaFactory
Throws
IllegalArgumentException | If no implementation of the schema language is available. |
---|---|
NullPointerException | If the schemaLanguage parameter is null. |
public Schema newSchema (File schema)
Parses the specified File
as a schema and returns it as a Schema
.
This is a convenience method for newSchema(Source)
.
Parameters
schema | File that represents a schema. |
---|
Returns
- New
Schema
from parsingschema
.
Throws
SAXException | If a SAX error occurs during parsing. |
---|---|
NullPointerException | if schema is null. |
public Schema newSchema (Source schema)
Parses the specified source as a schema and returns it as a schema.
This is a convenience method for newSchema(Source[])
.
Parameters
schema | Source that represents a schema. |
---|
Returns
- New
Schema
from parsingschema
.
Throws
SAXException | If a SAX error occurs during parsing. |
---|---|
NullPointerException | if schema is null. |
public abstract Schema newSchema ()
Creates a special Schema
object.
The exact semantics of the returned Schema
object depends
on the schema language that this SchemaFactory
is created
for.
Also, implementations are allowed to use implementation-specific property/feature to alter the semantics of this method.
W3C XML Schema 1.0
For XML Schema, this method creates a Schema
object that
performs validation by using location hints specified in documents.
The returned Schema
object assumes that if documents
refer to the same URL in the schema location hints,
they will always resolve to the same schema document. This
assumption allows implementations to reuse parsed results of
schema documents so that multiple validations against the same
schema will run faster.
Note that the use of schema location hints introduces a vulnerability to denial-of-service attacks.
RELAX NG
RELAX NG does not support this operation.
Returns
- Always return non-null valid
Schema
object.
Throws
UnsupportedOperationException | If this operation is not supported by the callee. |
---|---|
SAXException | If this operation is supported but failed for some reason. |
public abstract Schema newSchema (Source[] schemas)
Parses the specified source(s) as a schema and returns it as a schema.
The callee will read all the Source
s and combine them into a
single schema. The exact semantics of the combination depends on the schema
language that this SchemaFactory
object is created for.
When an ErrorHandler
is set, the callee will report all the errors
found in sources to the handler. If the handler throws an exception, it will
abort the schema compilation and the same exception will be thrown from
this method. Also, after an error is reported to a handler, the callee is allowed
to abort the further processing by throwing it. If an error handler is not set,
the callee will throw the first error it finds in the sources.
W3C XML Schema 1.0
The resulting schema contains components from the specified sources. The same result would be achieved if all these sources were imported, using appropriate values for schemaLocation and namespace, into a single schema document with a different targetNamespace and no components of its own, if the import elements were given in the same order as the sources. Section 4.2.3 of the XML Schema recommendation describes the options processors have in this regard. While a processor should be consistent in its treatment of JAXP schema sources and XML Schema imports, the behavior between JAXP-compliant parsers may vary; in particular, parsers may choose to ignore all but the first <import> for a given namespace, regardless of information provided in schemaLocation.
If the parsed set of schemas includes error(s) as
specified in the section 5.1 of the XML Schema spec, then
the error must be reported to the ErrorHandler
.
RELAX NG
For RELAX NG, this method must throw UnsupportedOperationException
if schemas.length!=1.
Parameters
schemas | inputs to be parsed. SchemaFactory is required
to recognize StreamSource ,
SAXSource ,
and DOMSource . |
---|
Returns
Throws
SAXException | If an error is found during processing the specified inputs.
When an ErrorHandler is set, errors are reported to
there first. See setErrorHandler(ErrorHandler) . |
---|---|
NullPointerException | If the schemas parameter itself is null or
any item in the array is null. |
IllegalArgumentException | If any item in the array is not recognized by this method. |
UnsupportedOperationException | If the schema language doesn't support this operation. |
public Schema newSchema (URL schema)
Parses the specified URL
as a schema and returns it as a Schema
.
This is a convenience method for newSchema(Source)
.
Parameters
schema | URL that represents a schema. |
---|
Returns
- New
Schema
from parsingschema
.
Throws
SAXException | If a SAX error occurs during parsing. |
---|---|
NullPointerException | if schema is null. |
public abstract void setErrorHandler (ErrorHandler errorHandler)
Sets the ErrorHandler
to receive errors encountered
during the newSchema
method invocation.
Error handler can be used to customize the error handling process
during schema parsing. When an ErrorHandler
is set,
errors found during the parsing of schemas will be first sent
to the ErrorHandler
.
The error handler can abort the parsing of a schema immediately
by throwing SAXException
from the handler. Or for example
it can print an error to the screen and try to continue the
processing by returning normally from the ErrorHandler
If any Throwable
(or instances of its derived classes)
is thrown from an ErrorHandler
,
the caller of the newSchema
method will be thrown
the same Throwable
object.
SchemaFactory
is not allowed to
throw SAXException
without first reporting it to
ErrorHandler
.
Applications can call this method even during a Schema
is being parsed.
When the ErrorHandler
is null, the implementation will
behave as if the following ErrorHandler
is set:
class DraconianErrorHandler implementsErrorHandler
{ public void fatalError(SAXParseException
e ) throwsSAXException
{ throw e; } public void error(SAXParseException
e ) throwsSAXException
{ throw e; } public void warning(SAXParseException
e ) throwsSAXException
{ // noop } }
When a new SchemaFactory
object is created, initially
this field is set to null. This field will NOT be
inherited to Schema
s, Validator
s, or
ValidatorHandler
s that are created from this SchemaFactory
.
Parameters
errorHandler | A new error handler to be set. This parameter can be null. |
---|
public void setFeature (String name, boolean value)
Set the value of a feature flag.
Feature can be used to control the way a SchemaFactory
parses schemas, although SchemaFactory
s are not required
to recognize any specific feature names.
The feature name is any fully-qualified URI. It is
possible for a SchemaFactory
to expose a feature value but
to be unable to change the current value.
All implementations are required to support the XMLConstants.FEATURE_SECURE_PROCESSING
feature.
When the feature is:
-
true
: the implementation will limit XML processing to conform to implementation limits. Examples include entity expansion limits and XML Schema constructs that would consume large amounts of resources. If XML processing is limited for security reasons, it will be reported via a call to the registeredErrorHandler.fatalError(org.xml.sax.SAXParseException)
. SeesetErrorHandler(ErrorHandler)
. -
false
: the implementation will processing XML according to the XML specifications without regard to possible implementation limits.
Parameters
name | The feature name, which is a non-null fully-qualified URI. |
---|---|
value | The requested value of the feature (true or false). |
Throws
SAXNotRecognizedException | If the feature value can't be assigned or retrieved. |
---|---|
SAXNotSupportedException | When the
SchemaFactory recognizes the feature name but
cannot set the requested value. |
NullPointerException | if the name parameter is null. |
See Also
public void setProperty (String name, Object object)
Set the value of a property.
The property name is any fully-qualified URI. It is
possible for a SchemaFactory
to recognize a property name but
to be unable to change the current value.
SchemaFactory
s are not required to recognize setting
any specific property names.
Parameters
name | The property name, which is a non-null fully-qualified URI. |
---|---|
object | The requested value for the property. |
Throws
SAXNotRecognizedException | If the property value can't be assigned or retrieved. |
---|---|
SAXNotSupportedException | When the
SchemaFactory recognizes the property name but
cannot set the requested value. |
NullPointerException | if the name parameter is null. |
public abstract void setResourceResolver (LSResourceResolver resourceResolver)
Sets the LSResourceResolver
to customize
resource resolution when parsing schemas.
SchemaFactory
uses a LSResourceResolver
when it needs to locate external resources while parsing schemas,
although exactly what constitutes "locating external resources" is
up to each schema language. For example, for W3C XML Schema,
this includes files <include>d or <import>ed,
and DTD referenced from schema files, etc.
Applications can call this method even during a Schema
is being parsed.
When the LSResourceResolver
is null, the implementation will
behave as if the following LSResourceResolver
is set:
class DumbDOMResourceResolver implementsLSResourceResolver
{ publicLSInput
resolveResource( String publicId, String systemId, String baseURI) { return null; // always return null } }
If a LSResourceResolver
throws a RuntimeException
(or instances of its derived classes),
then the SchemaFactory
will abort the parsing and
the caller of the newSchema
method will receive
the same RuntimeException
.
When a new SchemaFactory
object is created, initially
this field is set to null. This field will NOT be
inherited to Schema
s, Validator
s, or
ValidatorHandler
s that are created from this SchemaFactory
.
Parameters
resourceResolver | A new resource resolver to be set. This parameter can be null. |
---|