aoqi@0: /*
aoqi@0:  * Copyright (c) 1997, 2011, Oracle and/or its affiliates. All rights reserved.
aoqi@0:  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
aoqi@0:  *
aoqi@0:  * This code is free software; you can redistribute it and/or modify it
aoqi@0:  * under the terms of the GNU General Public License version 2 only, as
aoqi@0:  * published by the Free Software Foundation.  Oracle designates this
aoqi@0:  * particular file as subject to the "Classpath" exception as provided
aoqi@0:  * by Oracle in the LICENSE file that accompanied this code.
aoqi@0:  *
aoqi@0:  * This code is distributed in the hope that it will be useful, but WITHOUT
aoqi@0:  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
aoqi@0:  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
aoqi@0:  * version 2 for more details (a copy is included in the LICENSE file that
aoqi@0:  * accompanied this code).
aoqi@0:  *
aoqi@0:  * You should have received a copy of the GNU General Public License version
aoqi@0:  * 2 along with this work; if not, write to the Free Software Foundation,
aoqi@0:  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
aoqi@0:  *
aoqi@0:  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
aoqi@0:  * or visit www.oracle.com if you need additional information or have any
aoqi@0:  * questions.
aoqi@0:  */
aoqi@0: 
aoqi@0: package com.sun.xml.internal.bind.api;
aoqi@0: 
aoqi@0: import javax.xml.bind.JAXBContext;
aoqi@0: import javax.xml.bind.Unmarshaller;
aoqi@0: import javax.xml.bind.ValidationEventHandler;
aoqi@0: import javax.xml.bind.annotation.XmlAnyElement;
aoqi@0: 
aoqi@0: import com.sun.istack.internal.NotNull;
aoqi@0: import com.sun.istack.internal.Nullable;
aoqi@0: 
aoqi@0: /**
aoqi@0:  * Dynamically locates classes to represent elements discovered during the unmarshalling.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * <b>THIS INTERFACE IS SUBJECT TO CHANGE WITHOUT NOTICE.</b>
aoqi@0:  *
aoqi@0:  * <h2>Background</h2>
aoqi@0:  * <p>
aoqi@0:  * {@link JAXBContext#newInstance(Class...)} requires that application informs JAXB
aoqi@0:  * about all the classes that it may see in the instance document. While this allows
aoqi@0:  * JAXB to take time to optimize the unmarshalling, it is sometimes inconvenient
aoqi@0:  * for applications.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * This is where {@link ClassResolver} comes to resucue.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * A {@link ClassResolver} instance can be specified on {@link Unmarshaller} via
aoqi@0:  * {@link Unmarshaller#setProperty(String, Object)} as follows:
aoqi@0:  *
aoqi@0:  * <pre>
aoqi@0:  * unmarshaller.setProperty( ClassResolver.class.getName(), new MyClassResolverImpl() );
aoqi@0:  * </pre>
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * When an {@link Unmarshaller} encounters (i) an unknown root element or (ii) unknown
aoqi@0:  * elements where unmarshaller is trying to unmarshal into {@link XmlAnyElement} with
aoqi@0:  * <tt>lax=true</tt>, unmarshaller calls {@link #resolveElementName(String, String)}
aoqi@0:  * method to see if the application may be able to supply a class that corresponds
aoqi@0:  * to that class.
aoqi@0:  *
aoqi@0:  * <p>
aoqi@0:  * When a {@link Class} is returned, a new {@link JAXBContext} is created with
aoqi@0:  * all the classes known to it so far, plus a new class returned. This operation
aoqi@0:  * may fail (for example because of some conflicting annotations.) This failure
aoqi@0:  * is handled just like {@link Exception}s thrown from
aoqi@0:  * {@link ClassResolver#resolveElementName(String, String)}.
aoqi@0:  *
aoqi@0:  * @author Kohsuke Kawaguchi
aoqi@0:  * @since 2.1
aoqi@0:  */
aoqi@0: public abstract class ClassResolver {
aoqi@0:     /**
aoqi@0:      * JAXB calls this method when it sees an unknown element.
aoqi@0:      *
aoqi@0:      * <p>
aoqi@0:      * See the class javadoc for details.
aoqi@0:      *
aoqi@0:      * @param nsUri
aoqi@0:      *      Namespace URI of the unknown element. Can be empty but never null.
aoqi@0:      * @param localName
aoqi@0:      *      Local name of the unknown element. Never be empty nor null.
aoqi@0:      *
aoqi@0:      * @return
aoqi@0:      *      If a non-null class is returned, it will be used to unmarshal this element.
aoqi@0:      *      If null is returned, the resolution is assumed to be failed, and
aoqi@0:      *      the unmarshaller will behave as if there was no {@link ClassResolver}
aoqi@0:      *      to begin with (that is, to report it to {@link ValidationEventHandler},
aoqi@0:      *      then move on.)
aoqi@0:      *
aoqi@0:      * @throws Exception
aoqi@0:      *      Throwing any {@link RuntimeException} causes the unmarshaller to stop
aoqi@0:      *      immediately. The exception will be propagated up the call stack.
aoqi@0:      *      Throwing any other checked {@link Exception} results in the error
aoqi@0:      *      reproted to {@link ValidationEventHandler} (just like any other error
aoqi@0:      *      during the unmarshalling.)
aoqi@0:      */
aoqi@0:     public abstract @Nullable Class<?> resolveElementName(@NotNull String nsUri, @NotNull String localName) throws Exception;
aoqi@0: }