Class ValidatorHandler
- java.lang.Object
-
- javax.xml.validation.ValidatorHandler
- All Implemented Interfaces:
ContentHandler
public abstract class ValidatorHandler extends Object implements ContentHandler
Streaming validator that works on SAX stream.
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-specifiedContentHandler
will 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-specifiedContentHandler
will receive startPrefixMapping/endPrefixMapping events. If theValidatorHandler
introduces additional namespace bindings, the user-specifiedContentHandler
will receive additional startPrefixMapping/endPrefixMapping events. -
Attributes
for 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
Modifier | Constructor | Description |
---|---|---|
protected | ValidatorHandler() | Constructor for derived classes. |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
abstract ContentHandler | getContentHandler() | Gets the |
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 TypeInfoProvider | getTypeInfoProvider() | Obtains the |
abstract void | setContentHandler(ContentHandler receiver) | Sets the |
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
Methods declared in interface org.xml.sax.ContentHandler
characters, endDocument, endElement, endPrefixMapping, ignorableWhitespace, processingInstruction, setDocumentLocator, skippedEntity, startDocument, startElement, startPrefixMapping
Constructor Detail
ValidatorHandler
protected ValidatorHandler()
Constructor for derived classes.
The constructor does nothing.
Derived classes must create ValidatorHandler
objects that have null
ErrorHandler
and null
LSResourceResolver
.
Method Detail
setContentHandler
public abstract void setContentHandler(ContentHandler receiver)
Sets the ContentHandler
which receives the augmented validation result.
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
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-specifiedContentHandler
must be invoked for the same event before the callback returns. -
ValidatorHandler
may not introduce new elements that were not present in the input. -
ValidatorHandler
may not remove attributes that were present in the input.
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
- AContentHandler
or a null value.
getContentHandler
public abstract ContentHandler getContentHandler()
Gets the ContentHandler
which 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 thisValidatorHandler
has created. - See Also:
setContentHandler(ContentHandler)
setErrorHandler
public abstract void setErrorHandler(ErrorHandler errorHandler)
Sets the ErrorHandler
to receive errors encountered during the validation.
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.
getErrorHandler
public abstract ErrorHandler getErrorHandler()
Gets the current ErrorHandler
set to this ValidatorHandler
.
- 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 thisValidatorHandler
has created. - See Also:
setErrorHandler(ErrorHandler)
setResourceResolver
public abstract void setResourceResolver(LSResourceResolver resourceResolver)
Sets the LSResourceResolver
to customize resource resolution while in a validation episode.
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.
getResourceResolver
public abstract LSResourceResolver getResourceResolver()
Gets the current LSResourceResolver
set to this ValidatorHandler
.
- 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 thisValidatorHandler
has created. - See Also:
setErrorHandler(ErrorHandler)
getTypeInfoProvider
public abstract TypeInfoProvider getTypeInfoProvider()
Obtains the TypeInfoProvider
implementation of this ValidatorHandler
.
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 validTypeInfoProvider
.
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 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:
-
SAXNotRecognizedException
- If the feature value can't be assigned or retrieved. -
SAXNotSupportedException
- When theValidatorHandler
recognizes the feature name but cannot determine its value at this time. -
NullPointerException
- Whenname
isnull
. - See Also:
setFeature(String, boolean)
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 ValidatorHandler
parses schemas. 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. 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_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 theValidatorHandler
recognizes the feature name but cannot set the requested value. -
NullPointerException
- Whenname
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 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.
ValidatorHandler
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 theValidatorHandler
recognizes the property name but cannot set the requested value. -
NullPointerException
- Whenname
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 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.
ValidatorHandler
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
- Whenname
isnull
. - See Also:
setProperty(String, Object)