Class SchemaFactory
- java.lang.Object
-
- javax.xml.validation.SchemaFactory
public abstract class SchemaFactory extends Object
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 implementors 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 |
- Since:
- 1.5
Constructor Summary
Modifier | Constructor | Description |
---|---|---|
protected | SchemaFactory() | Constructor for derived classes. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
abstract ErrorHandler | getErrorHandler() | Gets the current |
boolean | getFeature(String name) | Look up the value of a feature flag. |
Object | getProperty(String name) | Look up the value of a property. |
abstract LSResourceResolver | getResourceResolver() | Gets the current |
abstract boolean | isSchemaLanguageSupported(String schemaLanguage) | Is specified schema supported by this |
static SchemaFactory | newDefaultInstance() | Creates a new instance of the |
static SchemaFactory | newInstance(String schemaLanguage) | Lookup an implementation of the |
static SchemaFactory | newInstance(String schemaLanguage,
String factoryClassName,
ClassLoader classLoader) | Obtain a new instance of a |
abstract Schema | newSchema() | Creates a special |
Schema | newSchema(File schema) | Parses the specified |
Schema | newSchema(URL schema) | Parses the specified |
Schema | newSchema(Source schema) | Parses the specified source as a schema and returns it as a schema. |
abstract Schema | newSchema(Source[] schemas) | Parses the specified source(s) as a schema and returns it as a schema. |
abstract void | setErrorHandler(ErrorHandler errorHandler) | Sets the |
void | setFeature(String name,
boolean value) | Set a feature for this |
void | setProperty(String name,
Object object) | Set the value of a property. |
abstract void | setResourceResolver(LSResourceResolver resourceResolver) | Sets the |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
SchemaFactory
protected SchemaFactory()
Constructor for derived classes.
The constructor does nothing.
Derived classes must create SchemaFactory
objects that have null
ErrorHandler
and null
LSResourceResolver
.
Method Detail
newDefaultInstance
public static SchemaFactory newDefaultInstance()
Creates a new instance of the SchemaFactory
builtin system-default implementation.
- Implementation Requirements:
- The
SchemaFactory
builtin system-default implementation is only required to support the W3C XML Schema 1.0, but may support additional schema languages. - Returns:
- A new instance of the
SchemaFactory
builtin system-default implementation. - Since:
- 9
newInstance
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:<i>schemaLanguage</i>"
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. -
Use the configuration file "jaxp.properties". The file is in standard
Properties
format and typically located in the conf directory of the Java installation. It contains the fully qualified name of the implementation class with the key being the system property defined above.The jaxp.properties file is read only once by the JAXP implementation and its values are then cached for future use. If the file does not exist when the first attempt is made to read from it, no further attempts are made to check for its existence. It is not possible to change the value of any property in jaxp.properties after it has been read for the first time.
-
Use the service-provider loading facility, defined by the
ServiceLoader
class, to attempt to locate and load an implementation of the service using the default loading mechanism: the service-provider loading facility will use the current thread's context class loader to attempt to load the service. If the context class loader is null, the system class loader will be used.
Each potential service provider is required to implement the methodisSchemaLanguageSupported(String schemaLanguage)
.
The first service provider found that supports the specified schema language is returned.
In case ofServiceConfigurationError
aSchemaFactoryConfigurationError
will be thrown. -
Platform default
SchemaFactory
is located in an 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 theschemaLanguage
parameter is null. -
SchemaFactoryConfigurationError
- If a configuration error is encountered. - See Also:
newInstance(String schemaLanguage, String factoryClassName, ClassLoader classLoader)
newInstance
public static SchemaFactory newInstance(String schemaLanguage, String factoryClassName, ClassLoader classLoader)
Obtain a new instance of a SchemaFactory
from class name. SchemaFactory
is returned if specified factory class name supports the specified schema language. This function is useful when there are multiple providers in the classpath. It gives more control to the application as it can specify which provider should be loaded.
Tip for Trouble-shooting
Setting the jaxp.debug
system property will cause this method to print a lot of debug messages to System.err
about what it is doing and where it is looking at.
If you have problems try:
java -Djaxp.debug=1 YourProgram ....
- Parameters:
-
schemaLanguage
- Specifies the schema language which the returnedSchemaFactory
will understand. See the list of available schema languages for the possible values. -
factoryClassName
- fully qualified factory class name that provides implementation ofjavax.xml.validation.SchemaFactory
. -
classLoader
-ClassLoader
used to load the factory class. Ifnull
currentThread
's context classLoader is used to load the factory class. - Returns:
- New instance of a
SchemaFactory
- Throws:
-
IllegalArgumentException
- iffactoryClassName
isnull
, or the factory class cannot be loaded, instantiated or doesn't support the schema language specified inschemLanguage
parameter. -
NullPointerException
- If theschemaLanguage
parameter is null. - Since:
- 1.6
- See Also:
newInstance(String schemaLanguage)
isSchemaLanguageSupported
public abstract boolean isSchemaLanguageSupported(String schemaLanguage)
Is specified schema supported by this SchemaFactory
?
- Parameters:
-
schemaLanguage
- Specifies the schema language which the returnedSchemaFactory
will understand.schemaLanguage
must specify a valid schema language. - Returns:
-
true
ifSchemaFactory
supportsschemaLanguage
, elsefalse
. - Throws:
-
NullPointerException
- IfschemaLanguage
isnull
. -
IllegalArgumentException
- IfschemaLanguage.length() == 0
orschemaLanguage
does not specify a valid schema language.
getFeature
public boolean getFeature(String name) throws SAXNotRecognizedException, SAXNotSupportedException
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.
Implementors 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 theSchemaFactory
recognizes the feature name but cannot determine its value at this time. -
NullPointerException
- Ifname
isnull
. - See Also:
setFeature(String, boolean)
setFeature
public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException
Set a feature for this SchemaFactory
, Schema
s created by this factory, and by extension, Validator
s and ValidatorHandler
s created by those Schema
s.
Implementors and developers should pay particular attention to how the special Schema
object returned by newSchema()
is processed. In some cases, for example, when the SchemaFactory
and the class actually loading the schema come from different implementations, it may not be possible for SchemaFactory
features to be inherited automatically. Developers should make sure that features, such as secure processing, are explicitly set in both places.
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(SAXParseException exception)
. SeesetErrorHandler(ErrorHandler 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 theSchemaFactory
recognizes the feature name but cannot set the requested value. -
NullPointerException
- Ifname
isnull
. - See Also:
getFeature(String)
setProperty
public void setProperty(String name, Object object) throws SAXNotRecognizedException, SAXNotSupportedException
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.
All implementations that implement JAXP 1.5 or newer are required to support the XMLConstants.ACCESS_EXTERNAL_DTD
and XMLConstants.ACCESS_EXTERNAL_SCHEMA
properties.
-
Access to external DTDs in Schema files is restricted to the protocols specified by the
XMLConstants.ACCESS_EXTERNAL_DTD
property. If access is denied during the creation of new Schema due to the restriction of this property,SAXException
will be thrown by thenewSchema(Source)
ornewSchema(File)
ornewSchema(URL)
ornewSchema(Source[])
method.Access to external DTDs in xml source files is restricted to the protocols specified by the
XMLConstants.ACCESS_EXTERNAL_DTD
property. If access is denied during validation due to the restriction of this property,SAXException
will be thrown by theValidator.validate(Source)
orValidator.validate(Source, Result)
method.Access to external reference set by the schemaLocation attribute is restricted to the protocols specified by the
XMLConstants.ACCESS_EXTERNAL_SCHEMA
property. If access is denied during validation due to the restriction of this property,SAXException
will be thrown by theValidator.validate(Source)
orValidator.validate(Source, Result)
method.Access to external reference set by the Import and Include element is restricted to the protocols specified by the
XMLConstants.ACCESS_EXTERNAL_SCHEMA
property. If access is denied during the creation of new Schema due to the restriction of this property,SAXException
will be thrown by thenewSchema(Source)
ornewSchema(File)
ornewSchema(URL)
ornewSchema(Source[])
method.
- 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 theSchemaFactory
recognizes the property name but cannot set the requested value. -
NullPointerException
- Ifname
isnull
.
getProperty
public Object getProperty(String name) throws SAXNotRecognizedException, SAXNotSupportedException
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.
Implementors 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
- Ifname
isnull
. - See Also:
setProperty(String, Object)
setErrorHandler
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 implements ErrorHandler { public void fatalError( SAXParseException e ) throws SAXException { throw e; } public void error( SAXParseException e ) throws SAXException { throw e; } public void warning( SAXParseException e ) throws SAXException { // 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 benull
.
getErrorHandler
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:
setErrorHandler(ErrorHandler)
setResourceResolver
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 implements LSResourceResolver { public LSInput 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.
getResourceResolver
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:
setErrorHandler(ErrorHandler)
newSchema
public Schema newSchema(Source schema) throws SAXException
Parses the specified source as a schema and returns it as a schema.
This is a convenience method for newSchema(Source[] schemas)
.
- Parameters:
-
schema
- Source that represents a schema. - Returns:
- New
Schema
from parsingschema
. - Throws:
-
SAXException
- If a SAX error occurs during parsing. -
NullPointerException
- ifschema
is null.
newSchema
public Schema newSchema(File schema) throws SAXException
Parses the specified File
as a schema and returns it as a Schema
.
This is a convenience method for newSchema(Source schema)
.
- Parameters:
-
schema
- File that represents a schema. - Returns:
- New
Schema
from parsingschema
. - Throws:
-
SAXException
- If a SAX error occurs during parsing. -
NullPointerException
- ifschema
is null.
newSchema
public Schema newSchema(URL schema) throws SAXException
Parses the specified URL
as a schema and returns it as a Schema
.
This is a convenience method for newSchema(Source schema)
.
- Parameters:
-
schema
-URL
that represents a schema. - Returns:
- New
Schema
from parsingschema
. - Throws:
-
SAXException
- If a SAX error occurs during parsing. -
NullPointerException
- ifschema
is null.
newSchema
public abstract Schema newSchema(Source[] schemas) throws SAXException
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 behaviour 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 recognizeSAXSource
,StreamSource
,StAXSource
, andDOMSource
. Input schemas must be XML documents or XML elements and must not be null. For backwards compatibility, the results of passing anything other than a document or element are implementation-dependent. Implementations must either recognize and process the input or thrown an IllegalArgumentException. - Returns:
- Always return a non-null valid
Schema
object. Note that when an error has been reported, there is no guarantee that the returnedSchema
object is meaningful. - Throws:
-
SAXException
- If an error is found during processing the specified inputs. When anErrorHandler
is set, errors are reported to there first. SeesetErrorHandler(ErrorHandler)
. -
NullPointerException
- If theschemas
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.
newSchema
public abstract Schema newSchema() throws SAXException
Creates a special Schema
object.
The exact semantics of the returned Schema
object depend on the schema language for which this SchemaFactory
is created.
Also, implementations are allowed to use implementation-specific property/feature to alter the semantics of this method.
Implementors and developers should pay particular attention to how the features set on this SchemaFactory
are processed by this special Schema
. In some cases, for example, when the SchemaFactory
and the class actually loading the schema come from different implementations, it may not be possible for SchemaFactory
features to be inherited automatically. Developers should make sure that features, such as secure processing, are explicitly set in both places.
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 asusmption 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.