/* Copyright 2002-2017 CS Systèmes d'Information
* Licensed to CS Systèmes d'Information (CS) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* CS licenses this file to You 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.orekit.time;
import java.io.Serializable;
import org.hipparchus.RealFieldElement;
/** Interface for time scales.
* <p>This is the interface representing all time scales. Time scales are related
* to each other by some offsets that may be discontinuous (for example
* the {@link UTCScale UTC scale} with respect to the {@link TAIScale
* TAI scale}).</p>
* @author Luc Maisonobe
* @see AbsoluteDate
*/
public interface TimeScale extends Serializable {
/** Get the offset to convert locations from {@link TAIScale} to instance.
* @param date conversion date
* @return offset in seconds to add to a location in <em>{@link TAIScale}
* time scale</em> to get a location in <em>instance time scale</em>
* @see #offsetToTAI(DateComponents, TimeComponents)
*/
double offsetFromTAI(AbsoluteDate date);
/** Get the offset to convert locations from {@link TAIScale} to instance.
* @param date conversion date
* @param <T> type of the filed elements
* @return offset in seconds to add to a location in <em>{@link TAIScale}
* time scale</em> to get a location in <em>instance time scale</em>
* @see #offsetToTAI(DateComponents, TimeComponents)
* @since 9.0
*/
<T extends RealFieldElement<T>> T offsetFromTAI(FieldAbsoluteDate<T> date);
/** Get the offset to convert locations from instance to {@link TAIScale}.
* @param date date location in the time scale
* @param time time location in the time scale
* @return offset in seconds to add to a location in <em>instance time scale</em>
* to get a location in <em>{@link TAIScale} time scale</em>
* @see #offsetFromTAI(AbsoluteDate)
*/
default double offsetToTAI(final DateComponents date, final TimeComponents time) {
final AbsoluteDate reference = new AbsoluteDate(date, time, TimeScalesFactory.getTAI());
double offset = 0;
for (int i = 0; i < 8; i++) {
offset = -offsetFromTAI(reference.shiftedBy(offset));
}
return offset;
}
/** Check if date is within a leap second introduction <em>in this time scale</em>.
* <p>
* This method will return false for all time scales that do <em>not</em>
* implement leap seconds, even if the date corresponds to a leap second
* in {@link UTCScale UTC scale}.
* </p>
* @param date date to check
* @return true if time is within a leap second introduction
*/
default boolean insideLeap(final AbsoluteDate date) {
return false;
}
/** Check if date is within a leap second introduction <em>in this time scale</em>.
* <p>
* This method will return false for all time scales that do <em>not</em>
* implement leap seconds, even if the date corresponds to a leap second
* in {@link UTCScale UTC scale}.
* </p>
* @param date date to check
* @param <T> type of the filed elements
* @return true if time is within a leap second introduction
* @since 9.0
*/
default <T extends RealFieldElement<T>> boolean insideLeap(final FieldAbsoluteDate<T> date) {
return false;
}
/** Check length of the current minute <em>in this time scale</em>.
* <p>
* This method will return 60 for all time scales that do <em>not</em>
* implement leap seconds, even if the date corresponds to a leap second
* in {@link UTCScale UTC scale}, and 61 for time scales that do implement
* leap second when the current date is within the last minute before the
* leap, or during the leap itself.
* </p>
* @param date date to check
* @return 60 or 61 depending on leap seconds introduction
*/
default int minuteDuration(final AbsoluteDate date) {
return 60;
}
/** Check length of the current minute <em>in this time scale</em>.
* <p>
* This method will return 60 for all time scales that do <em>not</em>
* implement leap seconds, even if the date corresponds to a leap second
* in {@link UTCScale UTC scale}, and 61 for time scales that do implement
* leap second when the current date is within the last minute before the
* leap, or during the leap itself.
* </p>
* @param date date to check
* @param <T> type of the filed elements
* @return 60 or 61 depending on leap seconds introduction
* @since 9.0
*/
default <T extends RealFieldElement<T>> int minuteDuration(final FieldAbsoluteDate<T> date) {
return 60;
}
/** Get the value of the previous leap.
* <p>
* This method will return 0.0 for all time scales that do <em>not</em>
* implement leap seconds.
* </p>
* @param date date to check
* @return value of the previous leap
*/
default double getLeap(final AbsoluteDate date) {
return 0;
}
/** Get the value of the previous leap.
* <p>
* This method will return 0.0 for all time scales that do <em>not</em>
* implement leap seconds.
* </p>
* @param date date to check
* @param <T> type of the filed elements
* @return value of the previous leap
* @since 9.0
*/
default <T extends RealFieldElement<T>> T getLeap(final FieldAbsoluteDate<T> date) {
return date.getField().getZero();
}
/** Get the name time scale.
* @return name of the time scale
*/
String getName();
}