https://github.com/eclipse-ee4j/jaxb-api/jakarta.xml.bind-api: Jakarta XML Binding API (Eclipse Foundation)
  • Roman Grigoriadi (Oracle Corporation) 
/*
 * Copyright (c) 2003, 2020 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 jakarta.xml.bind.helpers;

import org.xml.sax.InputSource;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import org.w3c.dom.Node;

import jakarta.xml.bind.JAXBException;
import jakarta.xml.bind.PropertyException;
import jakarta.xml.bind.UnmarshalException;
import jakarta.xml.bind.Unmarshaller;
import jakarta.xml.bind.ValidationEventHandler;
import jakarta.xml.bind.JAXBElement;
import jakarta.xml.bind.annotation.adapters.XmlAdapter;
import jakarta.xml.bind.attachment.AttachmentUnmarshaller;
import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParserFactory;
import javax.xml.stream.XMLEventReader;
import javax.xml.stream.XMLStreamReader;
import javax.xml.transform.Source;
import javax.xml.transform.dom.DOMSource;
import javax.xml.transform.sax.SAXSource;
import javax.xml.transform.stream.StreamSource;
import javax.xml.validation.Schema;
import java.io.*;
import java.net.URL;


Partial default Unmarshaller implementation. 
 This class provides a partial default implementation for the Unmarshallerinterface. 

A Jakarta XML Binding Provider has to implement five methods (getUnmarshallerHandler,
unmarshal(Node), unmarshal(XMLReader,InputSource),
unmarshal(XMLStreamReader), and unmarshal(XMLEventReader).

Author:
    
        
  • Kohsuke Kawaguchi, Sun Microsystems, Inc.
    • 
        
See Also:
Since:1.6, JAXB 1.0
/**
 * Partial default {@code Unmarshaller} implementation.
 * 
 * <p>
 * This class provides a partial default implementation for the
 * {@link jakarta.xml.bind.Unmarshaller}interface.
 * 
 * <p>
 * A Jakarta XML Binding Provider has to implement five methods (getUnmarshallerHandler,
 * unmarshal(Node), unmarshal(XMLReader,InputSource),
 * unmarshal(XMLStreamReader), and unmarshal(XMLEventReader).
 * 
 * @author <ul>
 *         <li>Kohsuke Kawaguchi, Sun Microsystems, Inc.</li>
 *         </ul>
 * @see jakarta.xml.bind.Unmarshaller
 * @since 1.6, JAXB 1.0
 */
public abstract class AbstractUnmarshallerImpl implements Unmarshaller
{    
    
handler that will be used to process errors and warnings during unmarshal 
/** handler that will be used to process errors and warnings during unmarshal */
    private ValidationEventHandler eventHandler = 
        new DefaultValidationEventHandler();
    
    
whether or not the unmarshaller will validate 
/** whether or not the unmarshaller will validate */
    protected boolean validating = false;

    
XMLReader that will be used to parse a document.

/**
     * XMLReader that will be used to parse a document.
     */
    private XMLReader reader = null;

    
Obtains a configured XMLReader. This method is used when the client-specified SAXSource object doesn't have XMLReader. Unmarshaller is not re-entrant, so we will only use one instance of XMLReader. 
/**
     * Obtains a configured XMLReader.
     * 
     * This method is used when the client-specified
     * {@link SAXSource} object doesn't have XMLReader.
     * 
     * {@link Unmarshaller} is not re-entrant, so we will
     * only use one instance of XMLReader.
     */
    protected XMLReader getXMLReader() throws JAXBException {
        if(reader==null) {
            try {
                SAXParserFactory parserFactory;
                parserFactory = SAXParserFactory.newInstance();
                parserFactory.setNamespaceAware(true);
                // there is no point in asking a validation because 
                // there is no guarantee that the document will come with
                // a proper schemaLocation.
                parserFactory.setValidating(false);
                reader = parserFactory.newSAXParser().getXMLReader();
            } catch( ParserConfigurationException e ) {
                throw new JAXBException(e);
            } catch( SAXException e ) {
                throw new JAXBException(e);
            }
        }
        return reader;
    }
    
    public Object unmarshal( Source source ) throws JAXBException {
        if( source == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "source" ) );
        }
        
        if(source instanceof SAXSource)
            return unmarshal( (SAXSource)source );
        if(source instanceof StreamSource)
            return unmarshal( streamSourceToInputSource((StreamSource)source));
        if(source instanceof DOMSource)
            return unmarshal( ((DOMSource)source).getNode() );
        
        // we don't handle other types of Source
        throw new IllegalArgumentException();
    }

    // use the client specified XMLReader contained in the SAXSource.
    private Object unmarshal( SAXSource source ) throws JAXBException {
        
        XMLReader r = source.getXMLReader();
        if( r == null )
            r = getXMLReader();
        
        return unmarshal( r, source.getInputSource() );
    }

    
Unmarshals an object by using the specified XMLReader and the InputSource.
The callee should call the setErrorHandler method of the XMLReader
so that errors are passed to the client-specified ValidationEventHandler.

/**
     * Unmarshals an object by using the specified XMLReader and the InputSource.
     * 
     * The callee should call the setErrorHandler method of the XMLReader
     * so that errors are passed to the client-specified ValidationEventHandler.
     */
    protected abstract Object unmarshal( XMLReader reader, InputSource source ) throws JAXBException;
    
    public final Object unmarshal( InputSource source ) throws JAXBException {
        if( source == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "source" ) );
        }

        return unmarshal( getXMLReader(), source );
    }
        

    private Object unmarshal( String url ) throws JAXBException {
        return unmarshal( new InputSource(url) );
    }
    
    public final Object unmarshal( URL url ) throws JAXBException {
        if( url == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "url" ) );
        }

        return unmarshal( url.toExternalForm() );
    }
    
    public final Object unmarshal( File f ) throws JAXBException {
        if( f == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "file" ) );
        }

        try {
            return unmarshal(new BufferedInputStream(new FileInputStream(f)));
        } catch( FileNotFoundException e ) {
            throw new IllegalArgumentException(e.getMessage());
        }
    }
    
    public final Object unmarshal( java.io.InputStream is ) 
        throws JAXBException {
            
        if( is == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "is" ) );
        }

        InputSource isrc = new InputSource( is );
        return unmarshal( isrc );
    }

    public final Object unmarshal( Reader reader ) throws JAXBException {
        if( reader == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "reader" ) );
        }

        InputSource isrc = new InputSource( reader );
        return unmarshal( isrc );
    }


    private static InputSource streamSourceToInputSource( StreamSource ss ) {
        InputSource is = new InputSource();
        is.setSystemId( ss.getSystemId() );
        is.setByteStream( ss.getInputStream() );
        is.setCharacterStream( ss.getReader() );
        
        return is;
    }
    
    
    
Indicates whether or not the Unmarshaller is configured to validate
during unmarshal operations.


Note: I named this method isValidating() to stay in-line
with JAXP, as opposed to naming it getValidating(). 

Throws:
  • JAXBException – if an error occurs while retrieving the validating
       flag
Returns:true if the Unmarshaller is configured to validate during
       unmarshal operations, false otherwise
/**
     * Indicates whether or not the Unmarshaller is configured to validate
     * during unmarshal operations.
     * <p>
     * <i><b>Note:</b> I named this method isValidating() to stay in-line
     * with JAXP, as opposed to naming it getValidating(). </i>
     *
     * @return true if the Unmarshaller is configured to validate during
     *        unmarshal operations, false otherwise
     * @throws JAXBException if an error occurs while retrieving the validating
     *        flag
     */
    public boolean isValidating() throws JAXBException {
        return validating;
    }
    
    
Allow an application to register a validation event handler.

 The validation event handler will be called by the Jakarta XML Binding Provider if any validation errors are encountered during calls to any of the unmarshal methods. If the client application does not register a validation event handler before invoking the unmarshal methods, then all validation events will be silently ignored and may result in unexpected behaviour. 
Params:
  • handler – the validation event handler
Throws:
  • JAXBException – if an error was encountered while setting the
       event handler
/**
     * Allow an application to register a validation event handler.
     * <p>
     * The validation event handler will be called by the Jakarta XML Binding Provider if any
     * validation errors are encountered during calls to any of the
     * {@code unmarshal} methods.  If the client application does not register
     * a validation event handler before invoking the unmarshal methods, then
     * all validation events will be silently ignored and may result in
     * unexpected behaviour.
     *
     * @param handler the validation event handler
     * @throws JAXBException if an error was encountered while setting the
     *        event handler
     */
    public void setEventHandler(ValidationEventHandler handler) 
        throws JAXBException {
        
        if( handler == null ) {
            eventHandler = new DefaultValidationEventHandler();
        } else {
            eventHandler = handler;
        }
    }
    
    
Specifies whether or not the Unmarshaller should validate during unmarshal operations. By default, the Unmarshaller does not validate. 

This method may only be invoked before or after calling one of the
unmarshal methods.

Params:
  • validating – true if the Unmarshaller should validate during
      unmarshal, false otherwise
Throws:
  • JAXBException – if an error occurred while enabling or disabling
validation at unmarshal time
/**
     * Specifies whether or not the Unmarshaller should validate during
     * unmarshal operations. By default, the {@code Unmarshaller} does
     * not validate.
     * <p>
     * This method may only be invoked before or after calling one of the
     * unmarshal methods.
     *
     * @param validating true if the Unmarshaller should validate during
     *       unmarshal, false otherwise
     * @throws JAXBException if an error occurred while enabling or disabling
     * validation at unmarshal time
     */
    public void setValidating(boolean validating) throws JAXBException {
        this.validating = validating;
    }
    
    
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
/**
     * 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
     */
    public ValidationEventHandler getEventHandler() throws JAXBException {
        return eventHandler;
    }
    
    
    
Creates an UnmarshalException from a SAXException.
This is an utility method provided for the derived classes.


When a provider-implemented ContentHandler wants to throw a
JAXBException, it needs to wrap the exception by a SAXException.
If the unmarshaller implementation blindly wrap SAXException
by JAXBException, such an exception will be a JAXBException
wrapped by a SAXException wrapped by another JAXBException.
This is silly.


This method checks the nested exception of SAXException
and reduce those excessive wrapping.

Returns:the resulting UnmarshalException
/**
     * Creates an UnmarshalException from a SAXException.
     * 
     * This is an utility method provided for the derived classes.
     * 
     * <p>
     * When a provider-implemented ContentHandler wants to throw a
     * JAXBException, it needs to wrap the exception by a SAXException.
     * If the unmarshaller implementation blindly wrap SAXException
     * by JAXBException, such an exception will be a JAXBException
     * wrapped by a SAXException wrapped by another JAXBException.
     * This is silly.
     * 
     * <p>
     * This method checks the nested exception of SAXException
     * and reduce those excessive wrapping.
     * 
     * @return the resulting UnmarshalException
     */
    protected UnmarshalException createUnmarshalException( SAXException e ) {
        // check the nested exception to see if it's an UnmarshalException
        Exception nested = e.getException();
        if(nested instanceof UnmarshalException)
            return (UnmarshalException)nested;
        
        if(nested instanceof RuntimeException)
            // typically this is an unexpected exception,
            // just throw it rather than wrap it, so that the full stack
            // trace can be displayed.
            throw (RuntimeException)nested;
                
        
        // otherwise simply wrap it
        if(nested!=null)
            return new UnmarshalException(nested);
        else
            return new UnmarshalException(e);
    }
    
    
Default implementation of the setProperty method always 
throws PropertyException since there are no required
properties. If a provider needs to handle additional 
properties, it should override this method in a derived class.

/**
     * Default implementation of the setProperty method always 
     * throws PropertyException since there are no required
     * properties. If a provider needs to handle additional 
     * properties, it should override this method in a derived class.
     */
    public void setProperty( String name, Object value )
        throws PropertyException {

        if( name == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "name" ) );
        }

        throw new PropertyException(name, value);
    }
    
    
Default implementation of the getProperty method always 
throws PropertyException since there are no required
properties. If a provider needs to handle additional 
properties, it should override this method in a derived class.

/**
     * Default implementation of the getProperty method always 
     * throws PropertyException since there are no required
     * properties. If a provider needs to handle additional 
     * properties, it should override this method in a derived class.
     */
    public Object getProperty( String name )
        throws PropertyException {
            
        if( name == null ) {
            throw new IllegalArgumentException(
                Messages.format( Messages.MUST_NOT_BE_NULL, "name" ) );
        }

        throw new PropertyException(name);
    }
    
    public Object unmarshal(XMLEventReader reader) throws JAXBException {
        
        throw new UnsupportedOperationException();
    }

    public Object unmarshal(XMLStreamReader reader) throws JAXBException {
        
        throw new UnsupportedOperationException();
    }

    public <T> JAXBElement<T> unmarshal(Node node, Class<T> expectedType) throws JAXBException {
        throw new UnsupportedOperationException();
    }

    public <T> JAXBElement<T> unmarshal(Source source, Class<T> expectedType) throws JAXBException {
        throw new UnsupportedOperationException();
    }

    public <T> JAXBElement<T> unmarshal(XMLStreamReader reader, Class<T> expectedType) throws JAXBException {
        throw new UnsupportedOperationException();
    }

    public <T> JAXBElement<T> unmarshal(XMLEventReader reader, Class<T> expectedType) throws JAXBException {
        throw new UnsupportedOperationException();
    }

    public void setSchema(Schema schema) {
        throw new UnsupportedOperationException();
    }

    public Schema getSchema() {
        throw new UnsupportedOperationException();
    }

    public void setAdapter(XmlAdapter adapter) {
        if(adapter==null)
            throw new IllegalArgumentException();
        setAdapter((Class)adapter.getClass(),adapter);
    }

    public <A extends XmlAdapter> void setAdapter(Class<A> type, A adapter) {
        throw new UnsupportedOperationException();
    }

    public <A extends XmlAdapter> A getAdapter(Class<A> type) {
        throw new UnsupportedOperationException();
    }

    public void setAttachmentUnmarshaller(AttachmentUnmarshaller au) {
        throw new UnsupportedOperationException();
    }

    public AttachmentUnmarshaller getAttachmentUnmarshaller() {
        throw new UnsupportedOperationException();
    }

    public void setListener(Listener listener) {
        throw new UnsupportedOperationException();
    }

    public Listener getListener() {
        throw new UnsupportedOperationException();
    }
}