/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
*/
package javax.xml.bind.annotation;
import javax.xml.bind.ValidationEventHandler;
import javax.xml.transform.Result;
import javax.xml.transform.Source;
/**
* Converts an element (and its descendants)
* from/to DOM (or similar) representation.
*
* <p>
* Implementations of this interface will be used in conjunction with
* {@link XmlAnyElement} annotation to map an element of XML into a representation
* of infoset such as W3C DOM.
*
* <p>
* Implementations hide how a portion of XML is converted into/from such
* DOM-like representation, allowing JAXB providers to work with arbitrary
* such library.
*
* <P>
* This interface is intended to be implemented by library writers
* and consumed by JAXB providers. None of those methods are intended to
* be called from applications.
*
* @author Kohsuke Kawaguchi
* @since JAXB2.0
*/
public interface DomHandler<ElementT,ResultT extends Result> {
/**
* When a JAXB provider needs to unmarshal a part of a document into an
* infoset representation, it first calls this method to create a
* {@link Result} object.
*
* <p>
* A JAXB provider will then send a portion of the XML
* into the given result. Such a portion always form a subtree
* of the whole XML document rooted at an element.
*
* @param errorHandler
* if any error happens between the invocation of this method
* and the invocation of {@link #getElement(Result)}, they
* must be reported to this handler.
*
* The caller must provide a non-null error handler.
*
* The {@link Result} object created from this method
* may hold a reference to this error handler.
*
* @return
* null if the operation fails. The error must have been reported
* to the error handler.
*/
ResultT createUnmarshaller( ValidationEventHandler errorHandler );
/**
* Once the portion is sent to the {@link Result}. This method is called
* by a JAXB provider to obtain the unmarshalled element representation.
*
* <p>
* Multiple invocations of this method may return different objects.
* This method can be invoked only when the whole sub-tree are fed
* to the {@link Result} object.
*
* @param rt
* The {@link Result} object created by {@link #createUnmarshaller(ValidationEventHandler)}.
*
* @return
* null if the operation fails. The error must have been reported
* to the error handler.
*/
ElementT getElement(ResultT rt);
/**
* This method is called when a JAXB provider needs to marshal an element
* to XML.
*
* <p>
* If non-null, the returned {@link Source} must contain a whole document
* rooted at one element, which will then be weaved into a bigger document
* that the JAXB provider is marshalling.
*
* @param errorHandler
* Receives any errors happened during the process of converting
* an element into a {@link Source}.
*
* The caller must provide a non-null error handler.
*
* @return
* null if there was an error. The error should have been reported
* to the handler.
*/
Source marshal( ElementT n, ValidationEventHandler errorHandler );
}
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