impl.com.sun.xml.bind.api.ClassResolver Maven / Gradle / Ivy
/*
* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.
*
* Copyright (c) 2010 Oracle and/or its affiliates. All rights reserved.
*
* The contents of this file are subject to the terms of either the GNU
* General Public License Version 2 only ("GPL") or the Common Development
* and Distribution License("CDDL") (collectively, the "License"). You
* may not use this file except in compliance with the License. You can
* obtain a copy of the License at
* https://glassfish.dev.java.net/public/CDDL+GPL_1_1.html
* or packager/legal/LICENSE.txt. See the License for the specific
* language governing permissions and limitations under the License.
*
* When distributing the software, include this License Header Notice in each
* file and include the License file at packager/legal/LICENSE.txt.
*
* GPL Classpath Exception:
* Oracle designates this particular file as subject to the "Classpath"
* exception as provided by Oracle in the GPL Version 2 section of the License
* file that accompanied this code.
*
* Modifications:
* If applicable, add the following below the License Header, with the fields
* enclosed by brackets [] replaced by your own identifying information:
* "Portions Copyright [year] [name of copyright owner]"
*
* Contributor(s):
* If you wish your version of this file to be governed by only the CDDL or
* only the GPL Version 2, indicate your decision by adding "[Contributor]
* elects to include this software in this distribution under the [CDDL or GPL
* Version 2] license." If you don't indicate a single choice of license, a
* recipient has the option to distribute your version of this file under
* either the CDDL, the GPL Version 2 or to extend the choice of license to
* its licensees as provided above. However, if you add GPL Version 2 code
* and therefore, elected the GPL Version 2 license, then the option applies
* only if the new code is made subject to such option by the copyright
* holder.
*/
package com.sun.xml.bind.api;
import javax.xml.bind.JAXBContext;
import javax.xml.bind.Unmarshaller;
import javax.xml.bind.ValidationEventHandler;
import javax.xml.bind.annotation.XmlAnyElement;
import com.sun.istack.NotNull;
import com.sun.istack.Nullable;
/**
* Dynamically locates classes to represent elements discovered during the unmarshalling.
*
*
* THIS INTERFACE IS SUBJECT TO CHANGE WITHOUT NOTICE.
*
*
Background
*
* {@link JAXBContext#newInstance(Class...)} requires that application informs JAXB
* about all the classes that it may see in the instance document. While this allows
* JAXB to take time to optimize the unmarshalling, it is sometimes inconvenient
* for applications.
*
*
* This is where {@link ClassResolver} comes to resucue.
*
*
* A {@link ClassResolver} instance can be specified on {@link Unmarshaller} via
* {@link Unmarshaller#setProperty(String, Object)} as follows:
*
*
* unmarshaller.setProperty( ClassResolver.class.getName(), new MyClassResolverImpl() );
*
*
*
* When an {@link Unmarshaller} encounters (i) an unknown root element or (ii) unknown
* elements where unmarshaller is trying to unmarshal into {@link XmlAnyElement} with
* lax=true, unmarshaller calls {@link #resolveElementName(String, String)}
* method to see if the application may be able to supply a class that corresponds
* to that class.
*
*
* When a {@link Class} is returned, a new {@link JAXBContext} is created with
* all the classes known to it so far, plus a new class returned. This operation
* may fail (for example because of some conflicting annotations.) This failure
* is handled just like {@link Exception}s thrown from
* {@link ClassResolver#resolveElementName(String, String)}.
*
* @author Kohsuke Kawaguchi
* @since 2.1
*/
public abstract class ClassResolver {
/**
* JAXB calls this method when it sees an unknown element.
*
*
* See the class javadoc for details.
*
* @param nsUri
* Namespace URI of the unknown element. Can be empty but never null.
* @param localName
* Local name of the unknown element. Never be empty nor null.
*
* @return
* If a non-null class is returned, it will be used to unmarshal this element.
* If null is returned, the resolution is assumed to be failed, and
* the unmarshaller will behave as if there was no {@link ClassResolver}
* to begin with (that is, to report it to {@link ValidationEventHandler},
* then move on.)
*
* @throws Exception
* Throwing any {@link RuntimeException} causes the unmarshaller to stop
* immediately. The exception will be propagated up the call stack.
* Throwing any other checked {@link Exception} results in the error
* reproted to {@link ValidationEventHandler} (just like any other error
* during the unmarshalling.)
*/
public abstract @Nullable Class resolveElementName(@NotNull String nsUri, @NotNull String localName) throws Exception;
}