/*

 * Copyright (c) 1996, 2003, 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.rmi;

/**

 * A {@code RemoteException} is the common superclass for a number of

 * communication-related exceptions that may occur during the execution of a

 * remote method call.  Each method of a remote interface, an interface that

 * extends {@code java.rmi.Remote}, must list

 * {@code RemoteException} in its throws clause.

 *

 * <p>As of release 1.4, this exception has been retrofitted to conform to

 * the general purpose exception-chaining mechanism.  The "wrapped remote

 * exception" that may be provided at construction time and accessed via

 * the public {@link #detail} field is now known as the <i>cause</i>, and

 * may be accessed via the {@link Throwable#getCause()} method, as well as

 * the aforementioned "legacy field."

 *

 * <p>Invoking the method {@link Throwable#initCause(Throwable)} on an

 * instance of {@code RemoteException} always throws {@link

 * IllegalStateException}.

 *

 * @author  Ann Wollrath

 * @since   1.1

 */

public class RemoteException extends java.io.IOException {

    /* indicate compatibility with JDK 1.1.x version of class */

    private static final long serialVersionUID = -5148567311918794206L;

    /**

     * The cause of the remote exception.

     *

     * <p>This field predates the general-purpose exception chaining facility.

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

     * obtaining this information.

     *

     * @serial

     */

    public Throwable detail;

    /**

     * Constructs a {@code RemoteException}.

     */

    public RemoteException() {

        initCause(null);  // Disallow subsequent initCause

    }

    /**

     * Constructs a {@code RemoteException} with the specified

     * detail message.

     *

     * @param s the detail message

     */

    public RemoteException(String s) {

        super(s);

        initCause(null);  // Disallow subsequent initCause

    }

    /**

     * Constructs a {@code RemoteException} with the specified detail

     * message and cause.  This constructor sets the {@link #detail}

     * field to the specified {@code Throwable}.

     *

     * @param s the detail message

     * @param cause the cause

     */

    public RemoteException(String s, Throwable cause) {

        super(s);

        initCause(null);  // Disallow subsequent initCause

        detail = cause;

    }

    /**

     * Returns the detail message, including the message from the cause, if

     * any, of this exception.

     *

     * @return the detail message

     */

    public String getMessage() {

        if (detail == null) {

            return super.getMessage();

        } else {

            return super.getMessage() + "; nested exception is: \n\t" +

                detail.toString();

        }

    }

    /**

     * Returns the cause of this exception.  This method returns the value

     * of the {@link #detail} field.

     *

     * @return  the cause, which may be {@code null}.

     * @since   1.4

     */

    public Throwable getCause() {

        return detail;

    }

}