1   /* Copyright 2002-2013 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.propagation.sampling;
18  
19  import org.orekit.errors.PropagationException;
20  import org.orekit.propagation.SpacecraftState;
21  import org.orekit.time.AbsoluteDate;
22  
23  /** This interface is a space-dynamics aware fixed size step handler.
24   *
25   * <p>It mirrors the <code>FixedStepHandler</code> interface from <a
26   * href="http://commons.apache.org/math/">commons-math</a> but provides
27   * a space-dynamics interface to the methods.</p>
28   * @author Luc Maisonobe
29   */
30  public interface OrekitFixedStepHandler {
31  
32      /** Initialize step handler at the start of a propagation.
33       * <p>
34       * This method is called once at the start of the propagation. It
35       * may be used by the step handler to initialize some internal data
36       * if needed.
37       * </p>
38       * @param s0 initial state
39       * @param t target time for the integration
40       * @exception PropagationException if step handler cannot be initialized
41       */
42      void init(SpacecraftState s0, AbsoluteDate t) throws PropagationException;
43  
44      /** Handle the current step.
45       * @param currentState current state at step time
46       * @param isLast if true, this is the last integration step
47       * @exception PropagationException if step cannot be handled
48       */
49      void handleStep(final SpacecraftState currentState, final boolean isLast)
50          throws PropagationException;
51  
52  }