/*
 * Copyright (c) 1997, 2020 Oracle and/or its affiliates and others.
 * All rights reserved.
 * Copyright 2004 The Apache Software Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package jakarta.servlet;

/**
 * Defines a general exception a servlet can throw when it encounters difficulty.
 *
 * @author Various
 */
public class ServletException extends Exception {

    private static final long serialVersionUID = 4221302886851315160L;

    private Throwable rootCause;

    /**
     * Constructs a new servlet exception.
     *
     */
    public ServletException() {
        super();
    }

    /**
     * Constructs a new servlet exception with the specified message. The message can be written to the server log and/or
     * displayed for the user.
     *
     * @param message a <code>String</code> specifying the text of the exception message
     *
     */
    public ServletException(String message) {
        super(message);
    }

    /**
     * Constructs a new servlet exception when the servlet needs to throw an exception and include a message about the "root
     * cause" exception that interfered with its normal operation, including a description message.
     *
     *
     * @param message a <code>String</code> containing the text of the exception message
     *
     * @param rootCause the <code>Throwable</code> exception that interfered with the servlet's normal operation, making
     * this servlet exception necessary
     *
     */
    public ServletException(String message, Throwable rootCause) {
        super(message, rootCause);
        this.rootCause = rootCause;
    }

    /**
     * Constructs a new servlet exception when the servlet needs to throw an exception and include a message about the "root
     * cause" exception that interfered with its normal operation. The exception's message is based on the localized message
     * of the underlying exception.
     *
     * <p>
     * This method calls the <code>getLocalizedMessage</code> method on the <code>Throwable</code> exception to get a
     * localized exception message. When subclassing <code>ServletException</code>, this method can be overridden to create
     * an exception message designed for a specific locale.
     *
     * @param rootCause the <code>Throwable</code> exception that interfered with the servlet's normal operation, making the
     * servlet exception necessary
     *
     */
    public ServletException(Throwable rootCause) {
        super(rootCause);
        this.rootCause = rootCause;
    }

    /**
     * Returns the exception that caused this servlet exception.
     *
     *
     * @return the <code>Throwable</code> that caused this servlet exception
     *
     */
    public Throwable getRootCause() {
        return rootCause;
    }
}
