/*

 * Copyright (c) 1996, 2020, 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

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 */

package java.lang;

import java.io.IOException;

import java.io.ObjectInputStream;

import java.io.ObjectOutputStream;

import java.io.ObjectStreamField;

/**

 * Signals that an unexpected exception has occurred in a static initializer.

 * An {@code ExceptionInInitializerError} is thrown to indicate that an

 * exception occurred during evaluation of a static initializer or the

 * initializer for a static variable.

 *

 * @author  Frank Yellin

 * @since   1.1

 */

public class ExceptionInInitializerError extends LinkageError {

    /**

     * Use serialVersionUID from JDK 1.1.X for interoperability

     */

    @java.io.Serial

    private static final long serialVersionUID = 1521711792217232256L;

    /**

     * Constructs an {@code ExceptionInInitializerError} with

     * {@code null} as its detail message string and with no saved

     * throwable object.

     * A detail message is a String that describes this particular exception.

     */

    public ExceptionInInitializerError() {

        initCause(null); // Disallow subsequent initCause

    }

    /**

     * Constructs a new {@code ExceptionInInitializerError} class by

     * saving a reference to the {@code Throwable} object thrown for

     * later retrieval by the {@link #getException()} method. The detail

     * message string is set to {@code null}.

     *

     * @param thrown The exception thrown

     */

    public ExceptionInInitializerError(Throwable thrown) {

        super(null, thrown); // Disallow subsequent initCause

    }

    /**

     * Constructs an {@code ExceptionInInitializerError} with the specified detail

     * message string.  A detail message is a String that describes this

     * particular exception. The detail message string is saved for later

     * retrieval by the {@link Throwable#getMessage()} method. There is no

     * saved throwable object.

     *

     * @param s the detail message

     */

    public ExceptionInInitializerError(String s) {

        super(s, null);  // Disallow subsequent initCause

    }

    /**

     * Returns the exception that occurred during a static initialization that

     * caused this error to be created.

     *

     * @apiNote

     * This method predates the general-purpose exception chaining facility.

     * The {@link Throwable#getCause()} method is now the preferred means of

     * obtaining this information.

     *

     * @return the saved throwable object of this

     *         {@code ExceptionInInitializerError}, or {@code null}

     *         if this {@code ExceptionInInitializerError} has no saved

     *         throwable object.

     */

    public Throwable getException() {

        return super.getCause();

    }

    /**

     * Serializable fields for ExceptionInInitializerError.

     *

     * @serialField exception Throwable the exception

     */

    @java.io.Serial

    private static final ObjectStreamField[] serialPersistentFields = {

        new ObjectStreamField("exception", Throwable.class)

    };

    /**

     * Reconstitutes the ExceptionInInitializerError instance from a stream

     * and initialize the cause properly when deserializing from an older

     * version.

     *

     * The getException and getCause method returns the private "exception"

     * field in the older implementation and ExceptionInInitializerError::cause

     * was set to null.

     *

     * @param  s the {@code ObjectInputStream} from which data is read

     * @throws IOException if an I/O error occurs

     * @throws ClassNotFoundException if a serialized class cannot be loaded

     */

    @java.io.Serial

    private void readObject(ObjectInputStream s) throws IOException, ClassNotFoundException {

        ObjectInputStream.GetField fields = s.readFields();

        Throwable exception = (Throwable) fields.get("exception", null);

        if (exception != null) {

            setCause(exception);

        }

    }

    /**

     * To maintain compatibility with older implementation, write a serial

     * "exception" field with the cause as the value.

     *

     * @param  out the {@code ObjectOutputStream} to which data is written

     * @throws IOException if an I/O error occurs

     */

    @java.io.Serial

    private void writeObject(ObjectOutputStream out) throws IOException {

        ObjectOutputStream.PutField fields = out.putFields();

        fields.put("exception", super.getCause());

        out.writeFields();

    }

}