Class ValidatorHandler
- All Implemented Interfaces:
ContentHandler
A ValidatorHandler object is not thread-safe and not reentrant.
In other words, it is the application's responsibility to make
sure that one ValidatorHandler object is not used from
more than one thread at any given time.
ValidatorHandler checks if the SAX events follow
the set of constraints described in the associated Schema,
and additionally it may modify the SAX events (for example
by adding default values, etc.)
ValidatorHandler extends from ContentHandler,
but it refines the underlying ContentHandler in
the following way:
- startElement/endElement events must receive non-null String
for
uri,localName, andqname, even though SAX allows some of them to be null. Similarly, the user-specifiedContentHandlerwill receive non-null Strings for all three parameters. - Applications must ensure that
ValidatorHandler'sContentHandler.startPrefixMapping(String,String)andContentHandler.endPrefixMapping(String)are invoked properly. Similarly, the user-specifiedContentHandlerwill receive startPrefixMapping/endPrefixMapping events. If theValidatorHandlerintroduces additional namespace bindings, the user-specifiedContentHandlerwill receive additional startPrefixMapping/endPrefixMapping events. Attributesfor theContentHandler.startElement(String,String,String,Attributes)method may or may not include xmlns* attributes.
A ValidatorHandler is automatically reset every time
the startDocument method is invoked.
Recognized Properties and Features
This spec defines the following feature that must be recognized
by all ValidatorHandler implementations.
http://xml.org/sax/features/namespace-prefixes
This feature controls how a ValidatorHandler introduces
namespace bindings that were not present in the original SAX event
stream.
When this feature is set to true, it must make
sure that the user's ContentHandler will see
the corresponding xmlns* attribute in
the Attributes object of the
ContentHandler.startElement(String,String,String,Attributes)
callback. Otherwise, xmlns* attributes must not be
added to Attributes that's passed to the
user-specified ContentHandler.
(Note that regardless of this switch, namespace bindings are
always notified to applications through
ContentHandler.startPrefixMapping(String,String) and
ContentHandler.endPrefixMapping(String) methods of the
ContentHandler specified by the user.)
Note that this feature does NOT affect the way
a ValidatorHandler receives SAX events. It merely
changes the way it augments SAX events.
This feature is set to false by default.
- Since:
- 1.5
-
Constructor Summary
Constructors -
Method Summary
Modifier and TypeMethodDescriptionabstract ContentHandlerGets theContentHandlerwhich receives the augmented validation result.abstract ErrorHandlerGets the currentErrorHandlerset to thisValidatorHandler.booleangetFeature(String name) Look up the value of a feature flag.getProperty(String name) Look up the value of a property.abstract LSResourceResolverGets the currentLSResourceResolverset to thisValidatorHandler.abstract TypeInfoProviderObtains theTypeInfoProviderimplementation of thisValidatorHandler.abstract voidsetContentHandler(ContentHandler receiver) Sets theContentHandlerwhich receives the augmented validation result.abstract voidsetErrorHandler(ErrorHandler errorHandler) Sets theErrorHandlerto receive errors encountered during the validation.voidsetFeature(String name, boolean value) Set a feature for thisValidatorHandler.voidsetProperty(String name, Object object) Set the value of a property.abstract voidsetResourceResolver(LSResourceResolver resourceResolver) Sets theLSResourceResolverto customize resource resolution while in a validation episode.Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, waitMethods declared in interface org.xml.sax.ContentHandler
characters, declaration, endDocument, endElement, endPrefixMapping, ignorableWhitespace, processingInstruction, setDocumentLocator, skippedEntity, startDocument, startElement, startPrefixMapping
-
Constructor Details
-
ValidatorHandler
protected ValidatorHandler()Constructor for derived classes.
The constructor does nothing.
Derived classes must create
ValidatorHandlerobjects that havenullErrorHandlerandnullLSResourceResolver.
-
-
Method Details
-
setContentHandler
Sets theContentHandlerwhich receives the augmented validation result.When a
ContentHandleris specified, aValidatorHandlerwill work as a filter and basically copy the incoming events to the specifiedContentHandler.In doing so, a
ValidatorHandlermay modify the events, for example by adding defaulted attributes.A
ValidatorHandlermay buffer events to certain extent, but to allowValidatorHandlerto be used by a parser, the following requirement has to be met.- When
ContentHandler.startElement(String, String, String, Attributes),ContentHandler.endElement(String, String, String),ContentHandler.startDocument(), orContentHandler.endDocument()are invoked on aValidatorHandler, the same method on the user-specifiedContentHandlermust be invoked for the same event before the callback returns. ValidatorHandlermay not introduce new elements that were not present in the input.ValidatorHandlermay not remove attributes that were present in the input.
When a callback method on the specified
ContentHandlerthrows an exception, the same exception object must be thrown from theValidatorHandler. TheErrorHandlershould not be notified of such an exception.This method can be called even during a middle of a validation.
- Parameters:
receiver- AContentHandleror a null value.
- When
-
getContentHandler
Gets theContentHandlerwhich receives the augmented validation result.- Returns:
- This method returns the object that was last set through
the
getContentHandler()method, or null if that method has never been called since thisValidatorHandlerhas created. - See Also:
-
setErrorHandler
Sets theErrorHandlerto receive errors encountered during the validation.Error handler can be used to customize the error handling process during a validation. When an
ErrorHandleris set, errors found during the validation will be first sent to theErrorHandler.The error handler can abort further validation immediately by throwing
SAXExceptionfrom the handler. Or for example it can print an error to the screen and try to continue the validation by returning normally from theErrorHandlerIf any
Throwableis thrown from anErrorHandler, the sameThrowableobject will be thrown toward the root of the call stack.ValidatorHandleris not allowed to throwSAXExceptionwithout first reporting it toErrorHandler.When the
ErrorHandleris null, the implementation will behave as if the followingErrorHandleris set:class DraconianErrorHandler implements
ErrorHandler{ public void fatalError(SAXParseExceptione ) throwsSAXException{ throw e; } public void error(SAXParseExceptione ) throwsSAXException{ throw e; } public void warning(SAXParseExceptione ) throwsSAXException{ // noop } }When a new
ValidatorHandlerobject is created, initially this field is set to null.- Parameters:
errorHandler- A new error handler to be set. This parameter can be null.
-
getErrorHandler
Gets the currentErrorHandlerset to thisValidatorHandler.- 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 thisValidatorHandlerhas created. - See Also:
-
setResourceResolver
Sets theLSResourceResolverto customize resource resolution while in a validation episode.ValidatorHandleruses aLSResourceResolverwhen it needs to locate external resources while a validation, although exactly what constitutes "locating external resources" is up to each schema language.When the
LSResourceResolveris null, the implementation will behave as if the followingLSResourceResolveris set:class DumbLSResourceResolver implements
LSResourceResolver{ publicLSInputresolveResource( String publicId, String systemId, String baseURI) { return null; // always return null } }If a
LSResourceResolverthrows aRuntimeException(or instances of its derived classes), then theValidatorHandlerwill abort the parsing and the caller of thevalidatemethod will receive the sameRuntimeException.When a new
ValidatorHandlerobject is created, initially this field is set to null.- Parameters:
resourceResolver- A new resource resolver to be set. This parameter can be null.
-
getResourceResolver
Gets the currentLSResourceResolverset to thisValidatorHandler.- 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 thisValidatorHandlerhas created. - See Also:
-
getTypeInfoProvider
Obtains theTypeInfoProviderimplementation of thisValidatorHandler.The obtained
TypeInfoProvidercan be queried during a parse to access the type information determined by the validator.Some schema languages do not define the notion of type, for those languages, this method may not be supported. However, to be compliant with this specification, implementations for W3C XML Schema 1.0 must support this operation.
- Returns:
- null if the validator / schema language does not support
the notion of
TypeInfo. Otherwise a non-null validTypeInfoProvider.
-
getFeature
Look up the value of a feature flag.The feature name is any fully-qualified URI. It is possible for a
ValidatorHandlerto recognize a feature name but temporarily be unable to return its value. Some feature values may be available only in specific contexts, such as before, during, or after a validation.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 theValidatorHandlerrecognizes the feature name but cannot determine its value at this time.NullPointerException- Whennameisnull.- See Also:
-
setFeature
public void setFeature(String name, boolean value) throws SAXNotRecognizedException, SAXNotSupportedException Set a feature for this
ValidatorHandler.Feature can be used to control the way a
ValidatorHandlerparses schemas. The feature name is any fully-qualified URI. It is possible for aSchemaFactoryto expose a feature value but to be unable to change the current value. Some feature values may be immutable or mutable only in specific contexts, such as before, during, or after a validation.All implementations are required to support the
XMLConstants.FEATURE_SECURE_PROCESSINGfeature. 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 theValidatorHandlerrecognizes the feature name but cannot set the requested value.NullPointerException- Whennameisnull.- See Also:
-
-
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
ValidatorHandlerto recognize a property name but to be unable to change the current value. Some property values may be immutable or mutable only in specific contexts, such as before, during, or after a validation.ValidatorHandlers 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 theValidatorHandlerrecognizes the property name but cannot set the requested value.NullPointerException- Whennameisnull.
-
getProperty
Look up the value of a property.The property name is any fully-qualified URI. It is possible for a
ValidatorHandlerto recognize a property name but temporarily be unable to return its value. Some property values may be available only in specific contexts, such as before, during, or after a validation.ValidatorHandlers 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- Whennameisnull.- See Also:
-