/*
 * Copyright (c) 2003, 2018 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.util;

import javax.xml.bind.JAXBContext;
import javax.xml.bind.JAXBException;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.UnmarshallerHandler;
import javax.xml.transform.sax.SAXResult;

JAXP Result implementation that unmarshals a JAXB object. 

This utility class is useful to combine JAXB with
other Java/XML technologies.

The following example shows how to use JAXB to unmarshal a document
resulting from an XSLT transformation.

   
      JAXBResult result = new JAXBResult(
        JAXBContext.newInstance("org.acme.foo") );
      
      // set up XSLT transformation
      TransformerFactory tf = TransformerFactory.newInstance();
      Transformer t = tf.newTransformer(new StreamSource("test.xsl"));
      
      // run transformation
      t.transform(new StreamSource("document.xml"),result);
      // obtain the unmarshalled content tree
      Object o = result.getResult();
   


The fact that JAXBResult derives from SAXResult is an implementation
detail. Thus in general applications are strongly discouraged from
accessing methods defined on SAXResult.

In particular it shall never attempt to call the setHandler, 
setLexicalHandler, and setSystemId methods.
Author:

	Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
Since:
1.6/**
 * JAXP {@link javax.xml.transform.Result} implementation
 * that unmarshals a JAXB object.
 * 
 * <p>
 * This utility class is useful to combine JAXB with
 * other Java/XML technologies.
 * 
 * <p>
 * The following example shows how to use JAXB to unmarshal a document
 * resulting from an XSLT transformation.
 * 
 * <blockquote>
 *    <pre>
 *       JAXBResult result = new JAXBResult(
 *         JAXBContext.newInstance("org.acme.foo") );
 *       
 *       // set up XSLT transformation
 *       TransformerFactory tf = TransformerFactory.newInstance();
 *       Transformer t = tf.newTransformer(new StreamSource("test.xsl"));
 *       
 *       // run transformation
 *       t.transform(new StreamSource("document.xml"),result);
 * 
 *       // obtain the unmarshalled content tree
 *       Object o = result.getResult();
 *    </pre>
 * </blockquote>
 * 
 * <p>
 * The fact that JAXBResult derives from SAXResult is an implementation
 * detail. Thus in general applications are strongly discouraged from
 * accessing methods defined on SAXResult.
 * 
 * <p>
 * In particular it shall never attempt to call the setHandler, 
 * setLexicalHandler, and setSystemId methods.
 * 
 * @author
 * 	Kohsuke Kawaguchi (kohsuke.kawaguchi@sun.com)
 * @since 1.6
 */
public class JAXBResult extends SAXResult {

    
Creates a new instance that uses the specified
JAXBContext to unmarshal.
Params:
context – The JAXBContext that will be used to create the
necessary Unmarshaller.  This parameter must not be null.
Throws:
JAXBException – if an error is encountered while creating the
JAXBResult or if the context parameter is null./**
     * Creates a new instance that uses the specified
     * JAXBContext to unmarshal.
     * 
     * @param context The JAXBContext that will be used to create the
     * necessary Unmarshaller.  This parameter must not be null.
     * @exception JAXBException if an error is encountered while creating the
     * JAXBResult or if the context parameter is null.
     */
    public JAXBResult( JAXBContext context ) throws JAXBException {
        this( ( context == null ) ? assertionFailed() : context.createUnmarshaller() );
    }
    
    
Creates a new instance that uses the specified
Unmarshaller to unmarshal an object.

This JAXBResult object will use the specified Unmarshaller
instance. It is the caller's responsibility not to use the
same Unmarshaller for other purposes while it is being
used by this object.

The primary purpose of this method is to allow the client
to configure Unmarshaller. Unless you know what you are doing,
it's easier and safer to pass a JAXBContext.
Params:
_unmarshaller – the unmarshaller.  This parameter must not be null.
Throws:
JAXBException – if an error is encountered while creating the
JAXBResult or the Unmarshaller parameter is null./**
     * Creates a new instance that uses the specified
     * Unmarshaller to unmarshal an object.
     * 
     * <p>
     * This JAXBResult object will use the specified Unmarshaller
     * instance. It is the caller's responsibility not to use the
     * same Unmarshaller for other purposes while it is being
     * used by this object.
     * 
     * <p>
     * The primary purpose of this method is to allow the client
     * to configure Unmarshaller. Unless you know what you are doing,
     * it's easier and safer to pass a JAXBContext.
     * 
     * @param _unmarshaller the unmarshaller.  This parameter must not be null.
     * @throws JAXBException if an error is encountered while creating the
     * JAXBResult or the Unmarshaller parameter is null.
     */
    public JAXBResult( Unmarshaller _unmarshaller ) throws JAXBException {
        if( _unmarshaller == null )
            throw new JAXBException( 
                Messages.format( Messages.RESULT_NULL_UNMARSHALLER ) );
            
        this.unmarshallerHandler = _unmarshaller.getUnmarshallerHandler();
        
        super.setHandler(unmarshallerHandler);
    }
    
    
Unmarshaller that will be used to unmarshal
the input documents.
/**
     * Unmarshaller that will be used to unmarshal
     * the input documents.
     */
    private final UnmarshallerHandler unmarshallerHandler;

    
Gets the unmarshalled object created by the transformation.
Throws:
IllegalStateException – 
	if this method is called before an object is unmarshalled.
JAXBException – 
     if there is any unmarshalling error.
     Note that the implementation is allowed to throw SAXException
     during the parsing when it finds an error.
Returns:

     Always return a non-null object./**
     * Gets the unmarshalled object created by the transformation.
     * 
     * @return
     *      Always return a non-null object.
     * 
     * @exception IllegalStateException
     * 	if this method is called before an object is unmarshalled.
     * 
     * @exception JAXBException
     *      if there is any unmarshalling error.
     *      Note that the implementation is allowed to throw SAXException
     *      during the parsing when it finds an error.
     */
    public Object getResult() throws JAXBException {
        return unmarshallerHandler.getResult();
    }
    
    
Hook to throw exception from the middle of a contructor chained call
to this
/**
     * Hook to throw exception from the middle of a contructor chained call
     * to this
     */
    private static Unmarshaller assertionFailed() throws JAXBException {
        throw new JAXBException( Messages.format( Messages.RESULT_NULL_CONTEXT ) );
    }
}