1 /* Copyright 2002-2024 CS GROUP 2 * Licensed to CS GROUP (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.time; 18 19 /** This interface represents objects that have a {@link AbsoluteDate} 20 * date attached to them. 21 * <p>Classes implementing this interface can be stored chronologically 22 * in sorted sets using {@link ChronologicalComparator} as the 23 * underlying comparator. An example using for {@link org.orekit.orbits.Orbit 24 * Orbit} instances is given here:</p> 25 * <pre> 26 * SortedSet<Orbit> sortedOrbits = 27 * new TreeSet<Orbit>(new ChronologicalComparator()); 28 * sortedOrbits.add(orbit1); 29 * sortedOrbits.add(orbit2); 30 * ... 31 * </pre> 32 * <p>This interface is also the base interface used to {@link 33 * org.orekit.utils.TimeStampedCache cache} series of time-dependent 34 * objects for interpolation in a thread-safe manner.</p> 35 * @see AbsoluteDate 36 * @see ChronologicalComparator 37 * @see org.orekit.utils.TimeStampedCache 38 * @author Luc Maisonobe 39 */ 40 public interface TimeStamped { 41 42 /** Get the date. 43 * @return date attached to the object 44 */ 45 AbsoluteDate getDate(); 46 47 /** Compute the physically elapsed duration between two instants. 48 * <p>The returned duration is the number of seconds physically 49 * elapsed between the two instants, measured in a regular time 50 * scale with respect to surface of the Earth (i.e either the {@link 51 * TAIScale TAI scale}, the {@link TTScale TT scale} or the {@link 52 * GPSScale GPS scale}). It is the only method that gives a 53 * duration with a physical meaning.</p> 54 * @param other instant to subtract from the instance 55 * @return offset in seconds between the two instants (positive 56 * if the instance is posterior to the argument) 57 * @see AbsoluteDate#durationFrom(AbsoluteDate) 58 * @since 12.0 59 */ 60 default double durationFrom(TimeStamped other) { 61 return getDate().durationFrom(other.getDate()); 62 } 63 64 }