001/*
002 *    GeoAPI - Java interfaces for OGC/ISO standards
003 *    Copyright © 2006-2023 Open Geospatial Consortium, Inc.
004 *    http://www.geoapi.org
005 *
006 *    Licensed under the Apache License, Version 2.0 (the "License");
007 *    you may not use this file except in compliance with the License.
008 *    You may obtain a copy of the License at
009 *
010 *        http://www.apache.org/licenses/LICENSE-2.0
011 *
012 *    Unless required by applicable law or agreed to in writing, software
013 *    distributed under the License is distributed on an "AS IS" BASIS,
014 *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 *    See the License for the specific language governing permissions and
016 *    limitations under the License.
017 */
018package org.opengis.temporal;
019
020import java.time.DateTimeException;
021import java.time.temporal.TemporalAmount;
022import org.opengis.annotation.UML;
023
024import static org.opengis.annotation.Obligation.*;
025import static org.opengis.annotation.Specification.*;
026
027
028/**
029 * A one-dimensional temporal primitive that represent extent in time.
030 * A period is an open interval bounded by beginning and ending points.
031 * Those two points <em>should</em> be of the same class. For example,
032 * if the {@linkplain #getBeginning() beginning} is an instance of {@link java.time.LocalDate},
033 * then the {@link #getEnding() ending} should also be an instance of {@code LocalDate}.
034 * If the two points are {@linkplain org.opengis.geometry.DirectPosition direct positions},
035 * then they <em>shall</em> be associated to the same {@linkplain org.opengis.referencing.crs.TemporalCRS}.
036 *
037 * @author  ISO 19108 (for abstract model and documentation)
038 * @author  Stephane Fellah (Image Matters)
039 * @author  Alexander Petkov
040 * @author  Martin Desruisseaux (Geomatys)
041 * @author  Remi Marechal (Geomatys).
042 * @since   3.1
043 * @version 3.1
044 */
045@UML(identifier="TM_Period", specification=ISO_19108)
046public interface Period extends TemporalPrimitive {
047    /**
048     * Returns the beginning instant at which this period starts.
049     * Its position on the timeline shall be before the period {@linkplain #getEnding() ending}.
050     *
051     * @return the beginning instant at which this period starts.
052     */
053    @UML(identifier="Beginning", obligation=MANDATORY, specification=ISO_19108)
054    Instant getBeginning();
055
056    /**
057     * Returns the ending instant at which this period ends.
058     * Its position on the timeline shall be after the period {@linkplain #getBeginning() beginning}.
059     *
060     * @return the ending instant at which this period ends.
061     */
062    @UML(identifier="Ending", obligation=MANDATORY, specification=ISO_19108)
063    Instant getEnding();
064
065    /**
066     * Returns the duration of this period (optional operation).
067     * This is the {@linkplain Instant#distance(TemporalPrimitive) distance}
068     * between the period beginning and ending positions.
069     * The default implementation is as below:
070     *
071     * {@snippet lang="java" :
072     * return getBeginning().distance(getEnding());
073     * }
074     *
075     * <h4>Exceptions</h4>
076     * This method shall throw an {@link IndeterminatePositionException} if the temporal
077     * position of a bound is {@linkplain Instant#getIndeterminatePosition() indeterminate}.
078     * A {@link DateTimeException} may also be thrown if the coordinates are
079     * {@link org.opengis.referencing.cs.CoordinateDataType#INTEGER ordinal values}.
080     *
081     * @return duration of this period.
082     * @throws UnsupportedOperationException if this operation is not supported.
083     * @throws IndeterminatePositionException if the temporal position of a bound is indeterminate.
084     * @throws DateTimeException if the duration cannot be computed between the temporal objects used as bounds.
085     * @throws ArithmeticException if the duration exceeds the capacity of the implementation.
086     *
087     * @see Instant#distance(TemporalPrimitive)
088     * @see java.time.Duration#between(Temporal, Temporal)
089     */
090    @UML(identifier="TM_Separation.length", obligation=OPTIONAL, specification=ISO_19108)
091    default TemporalAmount length() {
092        return getBeginning().distance(getEnding());
093    }
094}