https://github.com/eclipse-ee4j/jaxb-api/jakarta.xml.bind-api: Jakarta XML Binding API (Eclipse Foundation)
  • Roman Grigoriadi (Oracle Corporation) 
/*
 * Copyright (c) 2003, 2019 Oracle and/or its affiliates. All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Distribution License v. 1.0, which is available at
 * http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

package javax.xml.bind;


As of JAXB 2.0, this class is deprecated and optional.

 The Validator class is responsible for controlling the validation of content trees during runtime. 


Three Forms of Validation



   

       
Unmarshal-Time Validation

       
This form of validation enables a client application to receive information about validation errors and warnings detected while unmarshalling XML data into a Java content tree and is completely orthogonal to the other types of validation. To enable or disable it, see the javadoc for Unmarshaller.setValidating. All JAXB 1.0 Providers are required to support this operation. 

       
On-Demand Validation

       
 This form of validation enables a client application to receive information about validation errors and warnings detected in the Java content tree. At any point, client applications can call the Validator.validate method on the Java content tree (or any sub-tree of it). All JAXB 1.0 Providers are required to support this operation. 

       
Fail-Fast Validation

       
 This form of validation enables a client application to receive 
            immediate feedback about modifications to the Java content tree 
            that violate type constraints on Java Properties as defined in 
            the specification.  JAXB Providers are not required support
            this type of validation.  Of the JAXB Providers that do support
            this type of validation, some may require you to decide at schema
            compile time whether or not a client application will be allowed
            to request fail-fast validation at runtime.
       

   




 The Validator class is responsible for managing On-Demand Validation. The Unmarshaller class is responsible for managing Unmarshal-Time Validation during the unmarshal operations. Although there is no formal method of enabling validation during the marshal operations, the Marshaller may detect errors, which will be reported to the ValidationEventHandler registered on it. 


Using the Default EventHandler


 If the client application does not set an event handler on their Validator, Unmarshaller, or Marshaller prior to calling the validate, unmarshal, or marshal methods, then a default event handler will receive notification of any errors or warnings encountered. The default event handler will cause the current operation to halt after encountering the first error or fatal error (but will attempt to continue after receiving warnings). 




Handling Validation Events



  There are three ways to handle events encountered during the unmarshal,
  validate, and marshal operations:
   

       
Use the default event handler

       
The default event handler will be used if you do not specify one via the setEventHandler API's on Validator, Unmarshaller, or Marshaller. 

       
Implement and register a custom event handler

       
Client applications that require sophisticated event processing can implement the ValidationEventHandler interface and register it with the Unmarshaller and/or Validator. 

       
Use the ValidationEventCollector utility

       
For convenience, a specialized event handler is provided that simply collects any ValidationEvent objects created during the unmarshal, validate, and marshal operations and returns them to the client application as a java.util.Collection. 

   





Validation and Well-Formedness




 Validation events are handled differently depending on how the client application is configured to process them as described in the previous section. However, there are certain cases where a JAXB Provider indicates that it is no longer able to reliably detect and report errors. In these cases, the JAXB Provider will set the severity of the ValidationEvent to FATAL_ERROR to indicate that the unmarshal, validate, or marshal operations should be terminated. The default event handler and ValidationEventCollector utility class must terminate processing after being notified of a fatal error. Client applications that supply their own ValidationEventHandler should also terminate processing after being notified of a fatal error. If not, unexpected behaviour may occur. 




Supported Properties





There currently are not any properties required to be supported by all 
JAXB Providers on Validator.  However, some providers may support 
their own set of provider specific properties.



Author:
  • Ryan Shoemaker, Sun Microsystems, Inc.
  • Kohsuke Kawaguchi, Sun Microsystems, Inc.
  • Joe Fialli, Sun Microsystems, Inc.
See Also:
Since:1.6, JAXB 1.0
Deprecated:since JAXB 2.0
/**
 * As of JAXB 2.0, this class is deprecated and optional.
 * <p>
 * The {@code Validator} class is responsible for controlling the validation
 * of content trees during runtime.
 *
 * <p>
 * <a id="validationtypes"></a>
 * <b>Three Forms of Validation</b><br>
 * <blockquote>
 *    <dl>
 *        <dt><b>Unmarshal-Time Validation</b></dt>
 *        <dd>This form of validation enables a client application to receive 
 *            information about validation errors and warnings detected while
 *            unmarshalling XML data into a Java content tree and is completely 
 *            orthogonal to the other types of validation.  To enable or disable 
 *            it, see the javadoc for 
 *            {@link Unmarshaller#setValidating(boolean) Unmarshaller.setValidating}.
 *            All JAXB 1.0 Providers are required to support this operation.
 *        </dd>
 *
 *        <dt><b>On-Demand Validation</b></dt>
 *        <dd> This form of validation enables a client application to receive 
 *             information about validation errors and warnings detected in the 
 *             Java content tree.  At any point, client applications can call
 *             the {@link Validator#validate(Object) Validator.validate} method
 *             on the Java content tree (or any sub-tree of it).  All JAXB 1.0
 *             Providers are required to support this operation.
 *        </dd>
 *
 *        <dt><b>Fail-Fast Validation</b></dt>
 *        <dd> This form of validation enables a client application to receive 
 *             immediate feedback about modifications to the Java content tree 
 *             that violate type constraints on Java Properties as defined in 
 *             the specification.  JAXB Providers are not required support
 *             this type of validation.  Of the JAXB Providers that do support
 *             this type of validation, some may require you to decide at schema
 *             compile time whether or not a client application will be allowed
 *             to request fail-fast validation at runtime.
 *        </dd>
 *    </dl>
 * </blockquote>
 *
 * <p>
 * The {@code Validator} class is responsible for managing On-Demand Validation.
 * The {@code Unmarshaller} class is responsible for managing Unmarshal-Time
 * Validation during the unmarshal operations.  Although there is no formal
 * method of enabling validation during the marshal operations, the 
 * {@code Marshaller} may detect errors, which will be reported to the
 * {@code ValidationEventHandler} registered on it.
 *
 * <p>
 * <a id="defaulthandler"></a>
 * <b>Using the Default EventHandler</b><br>
 * <blockquote>
 *   If the client application does not set an event handler on their
 *   {@code Validator}, {@code Unmarshaller}, or {@code Marshaller} prior to
 *   calling the validate, unmarshal, or marshal methods, then a default event 
 *   handler will receive notification of any errors or warnings encountered.  
 *   The default event handler will cause the current operation to halt after 
 *   encountering the first error or fatal error (but will attempt to continue 
 *   after receiving warnings).
 * </blockquote>
 *
 * <p>
 * <a id="handlingevents"></a>
 * <b>Handling Validation Events</b><br>
 * <blockquote>
 *   There are three ways to handle events encountered during the unmarshal,
 *   validate, and marshal operations:
 *    <dl>
 *        <dt>Use the default event handler</dt>
 *        <dd>The default event handler will be used if you do not specify one
 *            via the {@code setEventHandler} API's on {@code Validator},
 *            {@code Unmarshaller}, or {@code Marshaller}.
 *        </dd>
 * 
 *        <dt>Implement and register a custom event handler</dt>
 *        <dd>Client applications that require sophisticated event processing
 *            can implement the {@code ValidationEventHandler} interface and
 *            register it with the {@code Unmarshaller} and/or
 *            {@code Validator}.
 *        </dd>
 *
 *        <dt>Use the {@link javax.xml.bind.util.ValidationEventCollector ValidationEventCollector} 
 *            utility</dt>
 *        <dd>For convenience, a specialized event handler is provided that
 *            simply collects any {@code ValidationEvent} objects created
 *            during the unmarshal, validate, and marshal operations and 
 *            returns them to the client application as a 
 *            {@code java.util.Collection}.
 *        </dd>
 *    </dl>
 * </blockquote>
 *
 * <p>
 * <b>Validation and Well-Formedness</b><br>
 * <blockquote>
 * <p>
 * Validation events are handled differently depending on how the client 
 * application is configured to process them as described in the previous
 * section.  However, there are certain cases where a JAXB Provider indicates
 * that it is no longer able to reliably detect and report errors.  In these
 * cases, the JAXB Provider will set the severity of the ValidationEvent to
 * FATAL_ERROR to indicate that the unmarshal, validate, or marshal operations 
 * should be terminated.  The default event handler and 
 * {@code ValidationEventCollector} utility class must terminate processing
 * after being notified of a fatal error.  Client applications that supply their 
 * own {@code ValidationEventHandler} should also terminate processing after
 * being notified of a fatal error.  If not, unexpected behaviour may occur.
 * </blockquote>
 *
 * <p>
 * <a id="supportedProps"></a>
 * <b>Supported Properties</b><br>
 * <blockquote>
 * <p>
 * There currently are not any properties required to be supported by all 
 * JAXB Providers on Validator.  However, some providers may support 
 * their own set of provider specific properties.
 * </blockquote>
 * 
 * 
 * @author <ul><li>Ryan Shoemaker, Sun Microsystems, Inc.</li><li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li><li>Joe Fialli, Sun Microsystems, Inc.</li></ul> 
 * @see JAXBContext
 * @see Unmarshaller
 * @see ValidationEventHandler
 * @see ValidationEvent
 * @see javax.xml.bind.util.ValidationEventCollector
 * @since 1.6, JAXB 1.0
 * @deprecated since JAXB 2.0
 */
public interface Validator {

    
Allow an application to register a validation event handler.

 The validation event handler will be called by the JAXB Provider if any validation errors are encountered during calls to validate. If the client application does not register a validation event handler before invoking the validate method, then validation events will be handled by the default event handler which will terminate the validate operation after the first error or fatal error is encountered. 

Calling this method with a null parameter will cause the Validator
to revert back to the default default event handler.

Params:
  • handler – the validation event handler
Throws:
  • JAXBException – if an error was encountered while setting the
        event handler
Deprecated:since JAXB2.0
/**
     * Allow an application to register a validation event handler.
     * <p>
     * The validation event handler will be called by the JAXB Provider if any
     * validation errors are encountered during calls to 
     * {@link #validate(Object) validate}.  If the client application does not 
     * register a validation event handler before invoking the validate method, 
     * then validation events will be handled by the default event handler which
     * will terminate the validate operation after the first error or fatal error
     * is encountered.
     * <p>
     * Calling this method with a null parameter will cause the Validator
     * to revert back to the default default event handler.
     *
     * @param handler the validation event handler
     * @throws JAXBException if an error was encountered while setting the
     *         event handler
     * @deprecated since JAXB2.0
     */
    public void setEventHandler( ValidationEventHandler handler )
        throws JAXBException;

    
Return the current event handler or the default event handler if one
hasn't been set.

Throws:
  • JAXBException – if an error was encountered while getting the 
        current event handler
Returns:the current ValidationEventHandler or the default event handler
        if it hasn't been set
Deprecated:since JAXB2.0
/**
     * Return the current event handler or the default event handler if one
     * hasn't been set.
     *
     * @return the current ValidationEventHandler or the default event handler
     *         if it hasn't been set
     * @throws JAXBException if an error was encountered while getting the 
     *         current event handler
     * @deprecated since JAXB2.0
     */
    public ValidationEventHandler getEventHandler()
        throws JAXBException;
        
    
Validate the Java content tree starting at subrootObj. 

Client applications can use this method to validate Java content trees
on-demand at runtime.  This method can be used to validate any arbitrary
subtree of the Java content tree.  Global constraint checking will not
 be performed as part of this operation (i.e. ID/IDREF constraints).

Params:
  • subrootObj – the obj to begin validation at
Throws:
Returns:true if the subtree rooted at subrootObj is valid, false otherwise
Deprecated:since JAXB2.0
/**
     * Validate the Java content tree starting at {@code subrootObj}.
     * <p>
     * Client applications can use this method to validate Java content trees
     * on-demand at runtime.  This method can be used to validate any arbitrary
     * subtree of the Java content tree.  Global constraint checking <b>will not
     * </b> be performed as part of this operation (i.e. ID/IDREF constraints).
     *
     * @param subrootObj the obj to begin validation at
     * @throws JAXBException if any unexpected problem occurs during validation
     * @throws ValidationException 
     *     If the {@link ValidationEventHandler ValidationEventHandler}
     *     returns false from its {@code handleEvent} method or the
     *     {@code Validator} is unable to validate the content tree rooted
     *     at {@code subrootObj}
     * @throws IllegalArgumentException
     *      If the subrootObj parameter is null
     * @return true if the subtree rooted at {@code subrootObj} is valid, false
     *         otherwise
     * @deprecated since JAXB2.0
     */
    public boolean validate( Object subrootObj ) throws JAXBException;
    
    
Validate the Java content tree rooted at rootObj. 

Client applications can use this method to validate Java content trees
on-demand at runtime.  This method is used to validate an entire Java
content tree.  Global constraint checking will be performed as 
part of this operation (i.e. ID/IDREF constraints).

Params:
  • rootObj – the root obj to begin validation at
Throws:
Returns:true if the tree rooted at rootObj is valid, false otherwise
Deprecated:since JAXB2.0
/**
     * Validate the Java content tree rooted at {@code rootObj}.
     * <p>
     * Client applications can use this method to validate Java content trees
     * on-demand at runtime.  This method is used to validate an entire Java
     * content tree.  Global constraint checking <b>will</b> be performed as 
     * part of this operation (i.e. ID/IDREF constraints).
     *
     * @param rootObj the root obj to begin validation at
     * @throws JAXBException if any unexpected problem occurs during validation
     * @throws ValidationException 
     *     If the {@link ValidationEventHandler ValidationEventHandler}
     *     returns false from its {@code handleEvent} method or the
     *     {@code Validator} is unable to validate the content tree rooted
     *     at {@code rootObj}
     * @throws IllegalArgumentException
     *      If the rootObj parameter is null
     * @return true if the tree rooted at {@code rootObj} is valid, false
     *         otherwise
     * @deprecated since JAXB2.0
     */
    public boolean validateRoot( Object rootObj ) throws JAXBException;

    
Set the particular property in the underlying implementation of Validator. This method can only be used to set one of the standard JAXB defined properties above or a provider specific property. Attempting to set an undefined property will result in a PropertyException being thrown. See 
Supported Properties.

Params:
  • name – the name of the property to be set. This value can either
             be specified using one of the constant fields or a user 
             supplied string.
  • value – the value of the property to be set
Throws:
Deprecated:since JAXB2.0
/**
     * Set the particular property in the underlying implementation of 
     * {@code Validator}.  This method can only be used to set one of
     * the standard JAXB defined properties above or a provider specific
     * property.  Attempting to set an undefined property will result in
     * a PropertyException being thrown.  See <a href="#supportedProps">
     * Supported Properties</a>.
     *
     * @param name the name of the property to be set. This value can either
     *              be specified using one of the constant fields or a user 
     *              supplied string.
     * @param value the value of the property to be set
     *
     * @throws PropertyException when there is an error processing the given
     *                            property or value
     * @throws IllegalArgumentException
     *      If the name parameter is null
     * @deprecated since JAXB2.0
     */
    public void setProperty( String name, Object value ) 
        throws PropertyException;
    
    
Get the particular property in the underlying implementation of Validator. This method can only be used to get one of the standard JAXB defined properties above or a provider specific property. Attempting to get an undefined property will result in a PropertyException being thrown. See 
Supported Properties.

Params:
  • name – the name of the property to retrieve
Throws:
Returns:the value of the requested property
Deprecated:since JAXB2.0
/**
     * Get the particular property in the underlying implementation of 
     * {@code Validator}.  This method can only be used to get one of
     * the standard JAXB defined properties above or a provider specific
     * property.  Attempting to get an undefined property will result in
     * a PropertyException being thrown.  See <a href="#supportedProps">
     * Supported Properties</a>.
     *
     * @param name the name of the property to retrieve
     * @return the value of the requested property
     *
     * @throws PropertyException
     *      when there is an error retrieving the given property or value
     *      property name
     * @throws IllegalArgumentException
     *      If the name parameter is null
     * @deprecated since JAXB2.0
     */
    public Object getProperty( String name ) throws PropertyException;
    
}