/*

 * Copyright (c) 1999, 2013, 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 javax.security.sasl;

import java.io.IOException;

/**

 * This class represents an error that has occurred when using SASL.

 *

 * @since 1.5

 *

 * @author Rosanna Lee

 * @author Rob Weltman

 */

public class SaslException extends IOException {

    /**

     * The possibly null root cause exception.

     * @serial

     */

    // Required for serialization interoperability with JSR 28

    private Throwable _exception;

    /**

     * Constructs a new instance of {@code SaslException}.

     * The root exception and the detailed message are null.

     */

    public SaslException () {

        super();

    }

    /**

     * Constructs a new instance of {@code SaslException} with a detailed message.

     * The root exception is null.

     * @param detail A possibly null string containing details of the exception.

     *

     * @see java.lang.Throwable#getMessage

     */

    public SaslException (String detail) {

        super(detail);

    }

    /**

     * Constructs a new instance of {@code SaslException} with a detailed message

     * and a root exception.

     * For example, a SaslException might result from a problem with

     * the callback handler, which might throw a NoSuchCallbackException if

     * it does not support the requested callback, or throw an IOException

     * if it had problems obtaining data for the callback. The

     * SaslException's root exception would be then be the exception thrown

     * by the callback handler.

     *

     * @param detail A possibly null string containing details of the exception.

     * @param ex A possibly null root exception that caused this exception.

     *

     * @see java.lang.Throwable#getMessage

     * @see #getCause

     */

    public SaslException (String detail, Throwable ex) {

        super(detail);

        if (ex != null) {

            initCause(ex);

        }

    }

    /*

     * Override Throwable.getCause() to ensure deserialized object from

     * JSR 28 would return same value for getCause() (i.e., _exception).

     */

    public Throwable getCause() {

        return _exception;

    }

    /*

     * Override Throwable.initCause() to match getCause() by updating

     * _exception as well.

     */

    public Throwable initCause(Throwable cause) {

        super.initCause(cause);

        _exception = cause;

        return this;

    }

    /**

     * Returns the string representation of this exception.

     * The string representation contains

     * this exception's class name, its detailed message, and if

     * it has a root exception, the string representation of the root

     * exception. This string representation

     * is meant for debugging and not meant to be interpreted

     * programmatically.

     * @return The non-null string representation of this exception.

     * @see java.lang.Throwable#getMessage

     */

    // Override Throwable.toString() to conform to JSR 28

    public String toString() {

        String answer = super.toString();

        if (_exception != null && _exception != this) {

            answer += " [Caused by " + _exception.toString() + "]";

        }

        return answer;

    }

    /** Use serialVersionUID from JSR 28 RI for interoperability */

    private static final long serialVersionUID = 4579784287983423626L;

}