/*
 * Copyright 1999-2004 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 org.apache.commons.jxpath;

/**
 * Thrown in various situations by JXPath; may contain a nested exception.
 *
 * @author Dmitri Plotnikov
 * @version $Revision: 1.5 $ $Date: 2004/02/29 14:17:42 $
 */

public class JXPathException extends RuntimeException {

    /** @serial */
    private Throwable exception;

    /**
     * Create a new JXPathException with no
     * detail mesage.
     */

     public JXPathException() {
         super();
         this.exception = null;
     }

    /**
     * Create a new JXPathException with
     * the String  specified as an error message.
     *
     * @param msg The error message for the exception.
     */
    public JXPathException(String msg) {
        super(msg);
        this.exception = null;
    }


    /**
     * Create a new JXPathException with a
     * given Throwable base cause of the error.
     *
     * @param e The exception to be encapsulated in a
     * JXPathException.
     */
    public JXPathException(Throwable e) {
        super(e.toString());
        this.exception = e;
    }

    /**
     * Create a new JXPathException with the
     * given Exception base cause and detail message.
     *
     * @param e The exception to be encapsulated in a
     * JXPathException
     * @param msg The detail message.
     */
    public JXPathException(String msg, Throwable e) {
        super(msg);
        this.exception = e;
    }


    /**
     * Return the message (if any) for this error . If there is no
     * message for the exception and there is an encapsulated
     * exception then the message of that exception will be returned.
     *
     * @return The error message.
     */
    public String getMessage() {
        String message = super.getMessage();

        if (exception != null) {
            if (message == null) {
                if (exception.getMessage() != null) {
                    return exception.getMessage();
                }
                else {
                    return exception.getClass().getName();
                }
            }
            else {
                if (exception.getMessage() != null) {
                    return message + "; " + exception.getMessage();
                }
                else {
                    return message + "; " + exception.getClass().getName();
                }
            }
        }

        return message;
    }

    /**
     * Return the actual exception (if any) that caused this exception to
     * be raised.
     *
     * @return The encapsulated exception, or null if there is none.
     */
    public Throwable getException() {
        return exception;
    }
}