/*

 * Copyright (c) 2006, 2012, Oracle and/or its affiliates. All rights reserved.

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

 * or visit www.oracle.com if you need additional information or have any

 * questions.

 */

package java.io;

/**

 * Context during upcalls from object stream to class-defined

 * readObject/writeObject methods.

 * Holds object currently being deserialized and descriptor for current class.

 *

 * This context keeps track of the thread it was constructed on, and allows

 * only a single call of defaultReadObject, readFields, defaultWriteObject

 * or writeFields which must be invoked on the same thread before the class's

 * readObject/writeObject method has returned.

 * If not set to the current thread, the getObj method throws NotActiveException.

 */

final class SerialCallbackContext {

    private final Object obj;

    private final ObjectStreamClass desc;

    /**

     * Thread this context is in use by.

     * As this only works in one thread, we do not need to worry about thread-safety.

     */

    private Thread thread;

    public SerialCallbackContext(Object obj, ObjectStreamClass desc) {

        this.obj = obj;

        this.desc = desc;

        this.thread = Thread.currentThread();

    }

    public Object getObj() throws NotActiveException {

        checkAndSetUsed();

        return obj;

    }

    public ObjectStreamClass getDesc() {

        return desc;

    }

    public void check() throws NotActiveException {

        if (thread != null && thread != Thread.currentThread()) {

            throw new NotActiveException(

                "expected thread: " + thread + ", but got: " + Thread.currentThread());

        }

    }

    private void checkAndSetUsed() throws NotActiveException {

        if (thread != Thread.currentThread()) {

             throw new NotActiveException(

              "not in readObject invocation or fields already read");

        }

        thread = null;

    }

    public void setUsed() {

        thread = null;

    }

}