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Validator (Java 2 Platform SE 5.0) - JDK 5 Documentation v1.5.0, Java 2 SDK 英文文档

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javax.xml.validation
Class Validator

java.lang.Object
  extended by javax.xml.validation.Validator

public abstract class Validator
extends Object

A processor that checks an XML document against Schema.

A validator is a thread-unsafe and non-reentrant object. 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.

Note that while the validate(javax.xml.transform.Source) and validate(javax.xml.transform.Source, javax.xml.transform.Result) methods take a Source instance, the Source instance must be a SAXSource or DOMSource.

Since:
1.5

Constructor Summary
protected Validator()
          Constructor for derived classes.
 
Method Summary
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 inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Constructor Detail

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 Detail

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 of: 

 validate(source,null);

Throws:
SAXException
IOException
See Also:
setErrorHandler(ErrorHandler)

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:

SAXSource DOMSource
null OK OK
SAXResult OK Err
DOMResult Err OK

Note that StreamSource instances are not allowed. To process a StreamSource, or 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 not be null.
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 specified source is neither SAXSource nor DOMSource.
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)

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 property 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.

Validators 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 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)
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2004 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.