/*

 * Copyright (c) 2010, 2011, 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.nio.file;

import java.util.ConcurrentModificationException;

import java.util.Objects;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.InvalidObjectException;

/**

 * Runtime exception thrown if an I/O error is encountered when iterating over

 * the entries in a directory. The I/O error is retrieved as an {@link

 * IOException} using the {@link #getCause() getCause()} method.

 *

 * @since 1.7

 * @see DirectoryStream

 */

public final class DirectoryIteratorException

    extends ConcurrentModificationException

{

    private static final long serialVersionUID = -6012699886086212874L;

    /**

     * Constructs an instance of this class.

     *

     * @param   cause

     *          the {@code IOException} that caused the directory iteration

     *          to fail

     *

     * @throws  NullPointerException

     *          if the cause is {@code null}

     */

    public DirectoryIteratorException(IOException cause) {

        super(Objects.requireNonNull(cause));

    }

    /**

     * Returns the cause of this exception.

     *

     * @return  the cause

     */

    @Override

    public IOException getCause() {

        return (IOException)super.getCause();

    }

    /**

     * Called to read the object from a stream.

     *

     * @throws  InvalidObjectException

     *          if the object is invalid or has a cause that is not

     *          an {@code IOException}

     */

    private void readObject(ObjectInputStream s)

        throws IOException, ClassNotFoundException

    {

        s.defaultReadObject();

        Throwable cause = super.getCause();

        if (!(cause instanceof IOException))

            throw new InvalidObjectException("Cause must be an IOException");

    }

}