javax.xml.validation
class ValidatorHandler

java.lang.Object javax.xml.validation.ValidatorHandler

All Implemented Interfaces:

ContentHandler

Most common way to construct:

Schema schema = …;

ValidatorHandler vh = schema.newValidatorHandler();

Based on 42 examples

public abstract class ValidatorHandler
extends Object
implements ContentHandler

Streaming validator that works on SAX stream.

A {@link ValidatorHandler} object is not thread-safe and not reentrant. 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:

1. 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.
2. 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.
3. {@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.

ValidatorHandler

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}.

getContentHandler

public abstract ContentHandler getContentHandler()

Gets the {@link ContentHandler} which receives the augmented validation result.

Returns:

This method returns the object that was last set through the {@link #getContentHandler()} method, or null if that method has never been called since this {@link ValidatorHandler} has created.

getErrorHandler

public abstract ErrorHandler getErrorHandler()

Gets the current {@link ErrorHandler} set to this {@link ValidatorHandler}.

Returns:

This method returns the object that was last set through the {@link #setErrorHandler(ErrorHandler)} method, or null if that method has never been called since this {@link ValidatorHandler} has created.

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 {@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.

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 the {@link ValidatorHandler} recognizes the feature name but cannot determine its value at this time.

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 {@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.

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.

getResourceResolver

public abstract LSResourceResolver getResourceResolver()

Gets the current {@link LSResourceResolver} set to this {@link ValidatorHandler}.

Returns:

This method returns the object that was last set through the {@link #setResourceResolver(LSResourceResolver)} method, or null if that method has never been called since this {@link ValidatorHandler} has created.

getTypeInfoProvider

public abstract 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.

Returns:

null if the validator / schema language does not support the notion of {@link org.w3c.dom.TypeInfo}. Otherwise a non-null valid {@link TypeInfoProvider}.

setContentHandler

public abstract void setContentHandler(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.

1. 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.
2. {@link ValidatorHandler} may not introduce new elements that were not present in the input.
3. {@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.

Parameters:

receiver - A {@link ContentHandler} or a null value.

setErrorHandler

public abstract void setErrorHandler(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.

Parameters:

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 a feature for this ValidatorHandler.

Feature can be used to control the way a {@link ValidatorHandler} parses schemas. The feature name is any fully-qualified URI. It is possible for a {@link 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 {@link javax.xml.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 {@link ErrorHandler#fatalError(SAXParseException exception)}. See {@link #setErrorHandler(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 the {@link ValidatorHandler} recognizes the feature name but cannot set the requested value.

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 {@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.

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 the {@link ValidatorHandler} recognizes the property name but cannot set the requested value.

setResourceResolver

public abstract void setResourceResolver(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.

Parameters:

resourceResolver - A new resource resolver to be set. This parameter can be null.