1   /* Copyright 2002-2018 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.OrekitException;
20  import org.orekit.propagation.SpacecraftState;
21  import org.orekit.time.AbsoluteDate;
22  
23  /** This interface is a space-dynamics aware step handler.
24   *
25   * <p>It mirrors the <code>StepHandler</code> interface from <a
26   * href="https://hipparchus.org/">Hipparchus</a> but
27   * provides a space-dynamics interface to the methods.</p>
28   * @author Luc Maisonobe
29   */
30  public interface OrekitStepHandler {
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       * <p>
39       * The default method does nothing
40       * </p>
41       * @param s0 initial state
42       * @param t target time for the integration
43       * @exception OrekitException if step handler cannot be initialized
44       */
45      default void init(SpacecraftState s0, AbsoluteDate t) throws OrekitException {
46          // nothing by default
47      }
48  
49      /** Handle the current step.
50       * @param interpolator interpolator set up for the current step
51       * @param isLast if true, this is the last integration step
52       * @exception OrekitException if step cannot be handled
53       */
54      void handleStep(OrekitStepInterpolator interpolator, boolean isLast)
55          throws OrekitException;
56  
57  }