/*
 * Copyright 2004-2005 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.tiles;

/**
 * Root class for all Tiles-exceptions.
 * @author Cedric Dumoulin
 */
public class TilesException extends Exception
{


  /**
   * Any "wrapped" exception will be exposed when this is serialized.
   * @serial
   */
  private Exception exception;
  /**
    * Constructor.
    */
  public TilesException() {
    super();
    this.exception = null;
  }

  /**
    * Constructor.
    * @param message The error or warning message.
    */
  public TilesException(String message) {
    super(message);
    this.exception = null;
  }


  /**
    * Create a new <code>TilesException</code> wrapping an existing exception.
    *
    * <p>The existing exception will be embedded in the new
    * one, and its message will become the default message for
    * the TilesException.</p>
    *
    * @param e The exception to be wrapped.
    */
  public TilesException(Exception e) {
    super();
    this.exception = e;
  }


  /**
    * Create a new <code>TilesException</code> from an existing exception.
    *
    * <p>The existing exception will be embedded in the new
    * one, but the new exception will have its own message.</p>
    *
    * @param message The detail message.
    * @param e The exception to be wrapped.
    */
  public TilesException(String message, Exception e) {
    super(message);
    this.exception = e;
  }


  /**
    * Return a detail message for this exception.
    *
    * <p>If there is a embedded exception, and if the TilesException
    * has no detail message of its own, this method will return
    * the detail message from the embedded exception.</p>
    *
    * @return The error or warning message.
    */
  public String getMessage () {
    String message = super.getMessage ();

    if (message == null && exception != null) {
      return exception.getMessage();
    } else {
      return message;
    }
  }


  /**
    * Return the embedded exception, if any.
    *
    * @return The embedded exception, or <code>null</code> if there is none.
    */
  public Exception getException () {
    return exception;
  }

}