javax.xml.validation
public abstract class ValidatorHandler extends Object implements ContentHandler
A ValidatorHandler object is a thread-unsafe, non-reentrant object. 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:
uri
, localName
, and qname
,
even though SAX allows some of them to be null.
Similarly, the user-specified ContentHandler will receive non-null
Strings for all three parameters.
A ValidatorHandler is automatically reset every time the startDocument method is invoked.
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
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 startPrefixMapping and endPrefixMapping 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
Version: $Revision: 446598 $, $Date: 2006-09-15 15:55:40 +0300 (Fri, 15 Sep 2006) $
Constructor Summary | |
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protected | ValidatorHandler()
Constructor for derived classes.
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Method Summary | |
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abstract ContentHandler | getContentHandler()
Gets the ContentHandler which receives the
augmented validation result.
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abstract ErrorHandler | getErrorHandler()
Gets the current ErrorHandler set to this ValidatorHandler.
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boolean | getFeature(String name)
Look up the value of a feature flag.
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Object | getProperty(String name)
Look up the value of a property.
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abstract LSResourceResolver | getResourceResolver()
Gets the current LSResourceResolver set to this ValidatorHandler.
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abstract TypeInfoProvider | getTypeInfoProvider()
Obtains the TypeInfoProvider implementation of this
ValidatorHandler.
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abstract void | setContentHandler(ContentHandler receiver)
Sets the ContentHandler which receives
the augmented validation result.
|
abstract void | setErrorHandler(ErrorHandler errorHandler)
Sets the ErrorHandler to receive errors encountered
during the validation.
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void | setFeature(String name, boolean value)
Set the value of a feature flag.
|
void | setProperty(String name, Object object)
Set the value of a property.
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abstract void | setResourceResolver(LSResourceResolver resourceResolver)
Sets the LSResourceResolver to customize
resource resolution while in a validation episode.
|
The constructor does nothing.
Derived classes must create ValidatorHandler objects that have null ErrorHandler and null LSResourceResolver.
Returns: This method returns the object that was last set through the getContentHandler method, or null if that method has never been called since this ValidatorHandler has created.
See Also: setContentHandler
Returns: This method returns the object that was last set through the setErrorHandler method, or null if that method has never been called since this ValidatorHandler has created.
See Also: setErrorHandler
The feature name is any fully-qualified URI. It is possible for a ValidatorHandler to 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: org.xml.sax.SAXNotRecognizedException If the feature value can't be assigned or retrieved. org.xml.sax.SAXNotSupportedException When the ValidatorHandler recognizes the feature name but cannot determine its value at this time. NullPointerException When the name parameter is null.
See Also: ValidatorHandler
The property name is any fully-qualified URI. It is possible for a ValidatorHandler to 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: org.xml.sax.SAXNotRecognizedException If the property value can't be assigned or retrieved. org.xml.sax.SAXNotSupportedException When the XMLReader recognizes the property name but cannot determine its value at this time. NullPointerException When the name parameter is null.
See Also: ValidatorHandler
Returns: This method returns the object that was last set through the setResourceResolver method, or null if that method has never been called since this ValidatorHandler has created.
See Also: setErrorHandler
The obtained TypeInfoProvider can 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 valid TypeInfoProvider.
When a ContentHandler is specified, a ValidatorHandler will work as a filter and basically copy the incoming events to the specified ContentHandler.
In doing so, a ValidatorHandler may modify the events, for example by adding defaulted attributes.
A ValidatorHandler may buffer events to certain extent, but to allow ValidatorHandler to be used by a parser, the following requirement has to be met.
When a callback method on the specified ContentHandler throws an exception, the same exception object must be thrown from the ValidatorHandler. The ErrorHandler should not be notified of such an exception.
This method can be called even during a middle of a validation.
Parameters: receiver A ContentHandler or a null value.
Error handler can be used to customize the error handling process during a validation. When an ErrorHandler is set, errors found during the validation will be first sent to the ErrorHandler.
The error handler can abort further validation immediately by throwing SAXException from the handler. Or for example it can print an error to the screen and try to continue the validation by returning normally from the ErrorHandler
If any Throwable is thrown from an ErrorHandler, the same Throwable object will be thrown toward the root of the call stack.
ValidatorHandler is not allowed to throw SAXException without first reporting it to ErrorHandler.
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 ValidatorHandler object is created, initially this field is set to null.
Parameters: errorHandler A new error handler to be set. This parameter can be null.
Feature can be used to control the way a ValidatorHandler parses schemas, although ValidatorHandlers are not required to recognize any specific property names.
The feature name is any fully-qualified URI. It is possible for a ValidatorHandler to 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.
Parameters: name The feature name, which is a non-null fully-qualified URI. value The requested value of the feature (true or false).
Throws: org.xml.sax.SAXNotRecognizedException If the feature value can't be assigned or retrieved. org.xml.sax.SAXNotSupportedException When the ValidatorHandler recognizes the feature name but cannot set the requested value. NullPointerException When the name parameter is null.
See Also: getFeature
The property name is any fully-qualified URI. It is possible for a ValidatorHandler to 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: org.xml.sax.SAXNotRecognizedException If the property value can't be assigned or retrieved. org.xml.sax.SAXNotSupportedException When the ValidatorHandler recognizes the property name but cannot set the requested value. NullPointerException When the name parameter is null.
ValidatorHandler uses a LSResourceResolver when it needs to locate external resources while a validation, although exactly what constitutes "locating external resources" is up to each schema language.
When the LSResourceResolver is null, the implementation will behave as if the following LSResourceResolver is set:
class DumbLSResourceResolver 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 ValidatorHandler will abort the parsing and
the caller of the validate
method will receive
the same RuntimeException.
When a new ValidatorHandler object is created, initially this field is set to null.
Parameters: resourceResolver A new resource resolver to be set. This parameter can be null.