/*******************************************************************************
 * Copyright (c) 2004, 2008 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.core.commands.common;

/**
 * Signals that an exception occured within the command architecture.
 * <p>
 * This class is not intended to be extended by clients.
 * </p>
 * 
 * @since 3.1
 * @noextend This class is not intended to be subclassed by clients.
 */
public abstract class CommandException extends Exception {
	
	/**
	 * Generated serial version UID for this class.
	 * 
	 * @since 3.4
	 */
	private static final long serialVersionUID = 5389763628699257234L;
	
	/**
	 * This member variable is required here to allow us to compile against JCL
	 * foundation libraries.  The value may be <code>null</code>.
	 */
	private Throwable cause;
	
    /**
     * Creates a new instance of this class with the specified detail message.
     * 
     * @param message
     *            the detail message; may be <code>null</code>.
     */
    public CommandException(final String message) {
        super(message);
    }

    /**
     * Creates a new instance of this class with the specified detail message
     * and cause.
     * 
     * @param message
     *            the detail message; may be <code>null</code>.
     * @param cause
     *            the cause; may be <code>null</code>.
     */
    public CommandException(final String message, final Throwable cause) {
        super(message);
        // don't pass the cause to super, to allow compilation against JCL Foundation
        this.cause = cause;
    }
    
    /**
     * Returns the cause of this throwable or <code>null</code> if the
     * cause is nonexistent or unknown. 
     * 
     * @return the cause or <code>null</code>
     */
    public Throwable getCause() {
        return cause;
    }
    
}
