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 implentors 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.
getErrorHandler
public abstract ErrorHandler getErrorHandler()
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.
name
- The feature name, which is a non-null fully-qualified URI.
- The current value of the feature (true or false).
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.
name
- The property name, which is a non-null fully-qualified URI.
- The current value of the property.
isSchemaLanguageSupported
public abstract boolean isSchemaLanguageSupported(String schemaLanguage)
Is specified schema supported by this SchemaFactory
?
schemaLanguage
- Specifies the schema language which the returned SchemaFactory
will understand.
schemaLanguage
must specify a valid schema language.
true
if SchemaFactory
supports schemaLanguage
, else false
.
newInstance
public static final 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:
isSchemaLanguageSupported(String schemaLanguage)
The first service provider found in class loader order that supports the specified schema language is returned.
-
Platform default
SchemaFactory
is located
in a implementation specific way. There must be a platform default
SchemaFactory
for W3C XML Schema.
If everything fails,
IllegalArgumentException
will be thrown.
Tip for Trouble-shooting:
See
java.util.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
- New instance of a
SchemaFactory
newSchema
public abstract Schema newSchema()
throws SAXException
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
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.
- Always return non-null valid
Schema
object.
SAXException
- If this operation is supported but failed for some reason.
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)
.
schema
- File that represents a schema.
- New
Schema
from parsing schema
.
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)
.
schema
- URL
that represents a schema.
- New
Schema
from parsing schema
.
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)
.
schema
- Source that represents a schema.
- New
Schema
from parsing schema
.
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.
- Always return a non-null valid
Schema
object.
Note that when an error has been reported, there is no
guarantee that the returned Schema
object is
meaningful.
setErrorHandler
public abstract void setErrorHandler(ErrorHandler errorHandler)
errorHandler
- A new error handler to be set. This parameter can be null.
setFeature
public void setFeature(String name,
boolean value)
throws SAXNotRecognizedException,
SAXNotSupportedException
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 enity 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 registered
ErrorHandler.fatalError(SAXParseException exception)
.
See setErrorHandler(ErrorHandler errorHandler)
.
-
false
: the implementation will processing XML according to the XML specifications without
regard to possible implementation limits.
name
- The feature name, which is a non-null fully-qualified URI.value
- The requested value of the feature (true or false).
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.
SchemaFactory
s are not required to recognize setting
any specific property names.
name
- The property name, which is a non-null fully-qualified URI.object
- The requested value for the property.
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
.
resourceResolver
- A new resource resolver to be set. This parameter can be null.