ValidatorHandlerpublic abstract class ValidatorHandler extends Object implements ContentHandler| Streaming validator that works on SAX stream.
A {@link ValidatorHandler} object is a thread-unsafe, non-reentrant object.
In other words, it is the application's responsibility to make
sure that one {@link ValidatorHandler} object is not used from
more than one thread at any given time.
{@link ValidatorHandler} checks if the SAX events follow
the set of constraints described in the associated {@link Schema},
and additionally it may modify the SAX events (for example
by adding default values, etc.)
{@link ValidatorHandler} extends from {@link ContentHandler},
but it refines the underlying {@link ContentHandler} in
the following way:
- startElement/endElement events must receive non-null String
for
uri, localName, and qname,
even though SAX allows some of them to be null.
Similarly, the user-specified {@link ContentHandler} will receive non-null
Strings for all three parameters.
- Applications must ensure that {@link ValidatorHandler}'s
{@link ContentHandler#startPrefixMapping(String,String)} and
{@link ContentHandler#endPrefixMapping(String)} are invoked
properly. Similarly, the user-specified {@link ContentHandler}
will receive startPrefixMapping/endPrefixMapping events.
If the {@link ValidatorHandler} introduces additional namespace
bindings, the user-specified {@link ContentHandler} will receive
additional startPrefixMapping/endPrefixMapping events.
- {@link org.xml.sax.Attributes} for the
{@link ContentHandler#startElement(String,String,String,Attributes)} method
may or may not include xmlns* attributes.
A {@link 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 {@link ValidatorHandler} implementations.
http://xml.org/sax/features/namespace-prefixes
This feature controls how a {@link 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 {@link ContentHandler} will see
the corresponding xmlns* attribute in
the {@link org.xml.sax.Attributes} object of the
{@link ContentHandler#startElement(String,String,String,Attributes)}
callback. Otherwise, xmlns* attributes must not be
added to {@link org.xml.sax.Attributes} that's passed to the
user-specified {@link ContentHandler}.
(Note that regardless of this switch, namespace bindings are
always notified to applications through
{@link ContentHandler#startPrefixMapping(String,String)} and
{@link ContentHandler#endPrefixMapping(String)} methods of the
{@link ContentHandler} specified by the user.)
Note that this feature does NOT affect the way
a {@link ValidatorHandler} receives SAX events. It merely
changes the way it augments SAX events.
This feature is set to false by default. |
| Constructors Summary |
|---|
protected ValidatorHandler()Constructor for derived classes.
The constructor does nothing.
Derived classes must create {@link ValidatorHandler} objects that have
null {@link ErrorHandler} and
null {@link LSResourceResolver}.
|
| Methods Summary |
|---|
| public abstract org.xml.sax.ContentHandler | getContentHandler()Gets the {@link ContentHandler} which receives the
augmented validation result.
| | public abstract org.xml.sax.ErrorHandler | getErrorHandler()Gets the current {@link ErrorHandler} set to this {@link ValidatorHandler}.
| | public boolean | getFeature(java.lang.String name)Look up the value of a feature flag.
The feature name is any fully-qualified URI. It is
possible for a {@link 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.
if(name==null)
throw new NullPointerException();
throw new SAXNotRecognizedException(name);
| | public java.lang.Object | getProperty(java.lang.String name)Look up the value of a property.
The property name is any fully-qualified URI. It is
possible for a {@link 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.
{@link 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.
if(name==null)
throw new NullPointerException();
throw new SAXNotRecognizedException(name);
| | public abstract org.w3c.dom.ls.LSResourceResolver | getResourceResolver()Gets the current {@link LSResourceResolver} set to this {@link ValidatorHandler}.
| | public abstract javax.xml.validation.TypeInfoProvider | getTypeInfoProvider()Obtains the {@link TypeInfoProvider} implementation of this
{@link ValidatorHandler}.
The obtained {@link 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.
| | public abstract void | setContentHandler(org.xml.sax.ContentHandler receiver)Sets the {@link ContentHandler} which receives
the augmented validation result.
When a {@link ContentHandler} is specified, a
{@link ValidatorHandler} will work as a filter
and basically copy the incoming events to the
specified {@link ContentHandler}.
In doing so, a {@link ValidatorHandler} may modify
the events, for example by adding defaulted attributes.
A {@link ValidatorHandler} may buffer events to certain
extent, but to allow {@link ValidatorHandler} to be used
by a parser, the following requirement has to be met.
- When
{@link ContentHandler#startElement(String, String, String, Attributes)},
{@link ContentHandler#endElement(String, String, String)},
{@link ContentHandler#startDocument()}, or
{@link ContentHandler#endDocument()}
are invoked on a {@link ValidatorHandler},
the same method on the user-specified {@link ContentHandler}
must be invoked for the same event before the callback
returns.
- {@link ValidatorHandler} may not introduce new elements that
were not present in the input.
- {@link ValidatorHandler} may not remove attributes that were
present in the input.
When a callback method on the specified {@link ContentHandler}
throws an exception, the same exception object must be thrown
from the {@link ValidatorHandler}. The {@link ErrorHandler}
should not be notified of such an exception.
This method can be called even during a middle of a validation.
| | public abstract void | setErrorHandler(org.xml.sax.ErrorHandler errorHandler)Sets the {@link ErrorHandler} to receive errors encountered
during the validation.
Error handler can be used to customize the error handling process
during a validation. When an {@link ErrorHandler} is set,
errors found during the validation will be first sent
to the {@link ErrorHandler}.
The error handler can abort further validation immediately
by throwing {@link org.xml.sax.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 {@link ErrorHandler}
If any {@link Throwable} is thrown from an {@link ErrorHandler},
the same {@link Throwable} object will be thrown toward the
root of the call stack.
{@link ValidatorHandler} is not allowed to
throw {@link org.xml.sax.SAXException} without first reporting it to
{@link ErrorHandler}.
When the {@link ErrorHandler} is null, the implementation will
behave as if the following {@link ErrorHandler} is set:
class DraconianErrorHandler implements {@link ErrorHandler} {
public void fatalError( {@link org.xml.sax.SAXParseException} e ) throws {@link org.xml.sax.SAXException} {
throw e;
}
public void error( {@link org.xml.sax.SAXParseException} e ) throws {@link org.xml.sax.SAXException} {
throw e;
}
public void warning( {@link org.xml.sax.SAXParseException} e ) throws {@link org.xml.sax.SAXException} {
// noop
}
}
When a new {@link ValidatorHandler} object is created, initially
this field is set to null.
| | public void | setFeature(java.lang.String name, boolean value)Set the value of a feature flag.
Feature can be used to control the way a {@link ValidatorHandler}
parses schemas, although {@link ValidatorHandler}s are not required
to recognize any specific property names.
The feature name is any fully-qualified URI. It is
possible for a {@link 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.
if(name==null)
throw new NullPointerException();
throw new SAXNotRecognizedException(name);
| | public void | setProperty(java.lang.String name, java.lang.Object object)Set the value of a property.
The property name is any fully-qualified URI. It is
possible for a {@link 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.
{@link ValidatorHandler}s are not required to recognize setting
any specific property names.
if(name==null)
throw new NullPointerException();
throw new SAXNotRecognizedException(name);
| | public abstract void | setResourceResolver(org.w3c.dom.ls.LSResourceResolver resourceResolver)Sets the {@link LSResourceResolver} to customize
resource resolution while in a validation episode.
{@link ValidatorHandler} uses a {@link 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 {@link LSResourceResolver} is null, the implementation will
behave as if the following {@link LSResourceResolver} is set:
class DumbLSResourceResolver implements {@link LSResourceResolver} {
public {@link org.w3c.dom.ls.LSInput} resolveResource(
String publicId, String systemId, String baseURI) {
return null; // always return null
}
}
If a {@link LSResourceResolver} throws a {@link RuntimeException}
(or instances of its derived classes),
then the {@link ValidatorHandler} will abort the parsing and
the caller of the validate method will receive
the same {@link RuntimeException}.
When a new {@link ValidatorHandler} object is created, initially
this field is set to null.
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