1   /* Copyright 2002-2016 CS Systèmes d'Information
2    * Licensed to CS Systèmes d'Information (CS) under one or more
3    * contributor license agreements.  See the NOTICE file distributed with
4    * this work for additional information regarding copyright ownership.
5    * CS licenses this file to You under the Apache License, Version 2.0
6    * (the "License"); you may not use this file except in compliance with
7    * the License.  You may obtain a copy of the License at
8    *
9    *   http://www.apache.org/licenses/LICENSE-2.0
10   *
11   * Unless required by applicable law or agreed to in writing, software
12   * distributed under the License is distributed on an "AS IS" BASIS,
13   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14   * See the License for the specific language governing permissions and
15   * limitations under the License.
16   */
17  package org.orekit.utils;
18  
19  import org.orekit.errors.OrekitException;
20  
21  
22  /** Interface for observing parameters changes.
23   * @see ParameterDriver
24   * @author Luc Maisonobe
25   * @since 8.0
26   */
27  public interface ParameterObserver {
28  
29      /** Notify that a parameter value has been changed.
30       * @param previousValue TODO
31       * @param driver parameter driver that has been changed
32       * @exception OrekitException if value is invalid for the driven model
33       */
34      void valueChanged(double previousValue, ParameterDriver driver) throws OrekitException;
35  
36  }