Module java.xml

Package javax.xml.validation

Class Validator

java.lang.Object

javax.xml.validation.Validator

public abstract class Validator
extends Object

A processor that checks an XML document against Schema.

A validator object is not thread-safe and not reentrant. In other words, it is the application's responsibility to make sure that one Validator object is not used from more than one thread at any given time, and while the validate method is invoked, applications may not recursively call the validate method.

Since:

1.5

Constructor Summary

Constructors

Modifier	Constructor	Description
protected	Validator()	Constructor for derived classes.

Method Summary

Modifier and Type	Method	Description
abstract ErrorHandler	getErrorHandler()	Gets the current ErrorHandler set to this Validator.
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 LSResourceResolver set to this Validator.
abstract void	reset()	Reset this Validator to its original configuration.
abstract void	setErrorHandler(ErrorHandler errorHandler)	Sets the ErrorHandler to receive errors encountered during the validate method invocation.
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.
abstract void	setResourceResolver(LSResourceResolver resourceResolver)	Sets the LSResourceResolver to customize resource resolution while in a validation episode.
void	validate(Source source)	Validates the specified input.
abstract void	validate(Source source, Result result)	Validates the specified input and send the augmented validation result to the specified output.

Methods declared in class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

Validator

protected Validator()

Constructor for derived classes.

The constructor does nothing.

Derived classes must create Validator objects that have null ErrorHandler and null LSResourceResolver.

Method Details

reset

public abstract void reset()

Reset this Validator to its original configuration.

Validator is reset to the same state as when it was created with Schema.newValidator(). reset() is designed to allow the reuse of existing Validators thus saving resources associated with the creation of new Validators.

The reset Validator is not guaranteed to have the same LSResourceResolver or ErrorHandler Objects, e.g. Object.equals(Object obj). It is guaranteed to have a functionally equal LSResourceResolver and ErrorHandler.

validate

public void validate(Source source)
              throws SAXException,
IOException

Validates the specified input.

This is just a convenience method for validate(Source source, Result result) with result of null.

Parameters:

source - XML to be validated. Must be an XML document or XML element and must not be null. For backwards compatibility, the results of attempting to validate anything other than a document or element are implementation-dependent. Implementations must either recognize and process the input or throw an IllegalArgumentException.

Throws:

IllegalArgumentException - If the Source is an XML artifact that the implementation cannot validate (for example, a processing instruction).

SAXException - If the ErrorHandler throws a SAXException or if a fatal error is found and the ErrorHandler returns normally.

IOException - If the validator is processing a SAXSource and the underlying XMLReader throws an IOException.

NullPointerException - If source is null.

See Also:

• validate(Source source, Result result)

validate

public abstract void validate(Source source,
 Result result)
                       throws SAXException,
IOException

Validates the specified input and send the augmented validation result to the specified output.

This method places the following restrictions on the types of the Source/Result accepted.

Source / Result Accepted

	StreamSource	SAXSource	DOMSource	StAXSource
null	OK	OK	OK	OK
StreamResult	OK	IllegalArgumentException	IllegalArgumentException	IllegalArgumentException
SAXResult	IllegalArgumentException	OK	IllegalArgumentException	IllegalArgumentException
DOMResult	IllegalArgumentException	IllegalArgumentException	OK	IllegalArgumentException
StAXResult	IllegalArgumentException	IllegalArgumentException	IllegalArgumentException	OK

To validate one Source into another kind of Result, use the identity transformer (see TransformerFactory.newTransformer()).

Errors found during the validation is sent to the specified ErrorHandler.

If a document is valid, or if a document contains some errors but none of them were fatal and the ErrorHandler didn't throw any exception, then the method returns normally.

Parameters:

source - XML to be validated. Must be an XML document or XML element and must not be null. For backwards compatibility, the results of attempting to validate anything other than a document or element are implementation-dependent. Implementations must either recognize and process the input or throw an IllegalArgumentException.

result - The Result object that receives (possibly augmented) XML. This parameter can be null if the caller is not interested in it. Note that when a DOMResult is used, a validator might just pass the same DOM node from DOMSource to DOMResult (in which case source.getNode()==result.getNode()), it might copy the entire DOM tree, or it might alter the node given by the source.

Throws:

IllegalArgumentException - If the Result type doesn't match the Source type or if the Source is an XML artifact that the implementation cannot validate (for example, a processing instruction).

SAXException - If the ErrorHandler throws a SAXException or if a fatal error is found and the ErrorHandler returns normally.

IOException - If the validator is processing a SAXSource and the underlying XMLReader throws an IOException.

NullPointerException - If the source parameter is null.

See Also:

• validate(Source source)

setErrorHandler

public abstract void setErrorHandler(ErrorHandler errorHandler)

Sets the ErrorHandler to receive errors encountered during the validate method invocation.

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 caller of the validate method will be thrown the same Throwable object.

Validator 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 Validator 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 Validator.

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 this Validator 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.

Validator 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 Validator will abort the parsing and the caller of the validate method will receive the same RuntimeException.

When a new Validator 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 Validator.

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 this Validator has created.

See Also:

• setErrorHandler(ErrorHandler)

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 Validator 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 Validator recognizes the feature name but cannot determine its value at this time.

NullPointerException - When the name parameter is null.

See Also:

• setFeature(String, boolean)

setFeature

public void setFeature(String name,
 boolean value)
                throws SAXNotRecognizedException,
SAXNotSupportedException

Set the value of a feature flag.

Feature can be used to control the way a Validator parses schemas, although Validators are not required to recognize any specific feature names.

The feature name is any fully-qualified URI. It is possible for a Validator 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:

SAXNotRecognizedException - If the feature value can't be assigned or retrieved.

SAXNotSupportedException - When the Validator recognizes the feature name but cannot set the requested value.

NullPointerException - When the name parameter is null.

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 Validator 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.

All implementations that implement JAXP 1.5 or newer are required to support the XMLConstants.ACCESS_EXTERNAL_DTD and XMLConstants.ACCESS_EXTERNAL_SCHEMA properties.

• Access to external DTDs in source or Schema file is restricted to the protocols specified by the XMLConstants.ACCESS_EXTERNAL_DTD property. If access is denied during validation due to the restriction of this property, SAXException will be thrown by the validate(Source) method.

  Access to external reference set by the schemaLocation attribute is restricted to the protocols specified by the XMLConstants.ACCESS_EXTERNAL_SCHEMA property. If access is denied during validation due to the restriction of this property, SAXException will be thrown by the validate(Source) method.

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 Validator recognizes the property name but cannot set the requested value.

NullPointerException - When the name parameter is null.

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 Validator 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.

Validators 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 - When the name parameter is null.

See Also:

• setProperty(String, Object)