001 /*
002 * GeoAPI - Java interfaces for OGC/ISO standards
003 * http://www.geoapi.org
004 *
005 * Copyright (C) 2004-2012 Open Geospatial Consortium, Inc.
006 * All Rights Reserved. http://www.opengeospatial.org/ogc/legal
007 *
008 * Permission to use, copy, and modify this software and its documentation, with
009 * or without modification, for any purpose and without fee or royalty is hereby
010 * granted, provided that you include the following on ALL copies of the software
011 * and documentation or portions thereof, including modifications, that you make:
012 *
013 * 1. The full text of this NOTICE in a location viewable to users of the
014 * redistributed or derivative work.
015 * 2. Notice of any changes or modifications to the OGC files, including the
016 * date changes were made.
017 *
018 * THIS SOFTWARE AND DOCUMENTATION IS PROVIDED "AS IS," AND COPYRIGHT HOLDERS MAKE
019 * NO REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
020 * TO, WARRANTIES OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE OR THAT
021 * THE USE OF THE SOFTWARE OR DOCUMENTATION WILL NOT INFRINGE ANY THIRD PARTY
022 * PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER RIGHTS.
023 *
024 * COPYRIGHT HOLDERS WILL NOT BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL OR
025 * CONSEQUENTIAL DAMAGES ARISING OUT OF ANY USE OF THE SOFTWARE OR DOCUMENTATION.
026 *
027 * The name and trademarks of copyright holders may NOT be used in advertising or
028 * publicity pertaining to the software without specific, written prior permission.
029 * Title to copyright in this software and any associated documentation will at all
030 * times remain with copyright holders.
031 */
032 package org.opengis.geometry.coordinate;
033
034 import org.opengis.geometry.DirectPosition;
035 import org.opengis.geometry.primitive.Point;
036 import org.opengis.annotation.UML;
037
038 import static org.opengis.annotation.Obligation.*;
039 import static org.opengis.annotation.Specification.*;
040
041
042 /**
043 * A type consisting of either a {@linkplain DirectPosition direct position} or of a
044 * {@linkplain Point point} from which a {@linkplain DirectPosition direct position}
045 * shall be obtained. The use of this data type allows the identification of a position
046 * either directly as a coordinate (variant direct) or indirectly as a {@linkplain Point point}
047 * (variant indirect).
048 *
049 * @departure constraint
050 * ISO 19107 defines <code>Position</code> as a <code>union</code> of
051 * <code>DirectPosition</code> and <code>Point</code> but unions are not allowed in Java.
052 * GeoAPI defines <code>Position</code> as the base interface of both types so the two
053 * conditional accessor methods, <code>getPoint()</code> and <code>getDirectPosition()</code>,
054 * can be replaced by an <code>instanceof</code> check. However, the
055 * <code>getDirectPosition()</code> has been retained with different semantics, conceptually
056 * returning a <code>DirectPosition</code> at the same location. The conditionality has also
057 * been changed to mandatory since all three types conceptually have a well defined location.
058 *
059 * @author Martin Desruisseaux (IRD)
060 * @version 3.0
061 * @since 1.0
062 *
063 * @issue http://jira.codehaus.org/browse/GEO-87
064 */
065 @UML(identifier="GM_Position", specification=ISO_19107)
066 public interface Position {
067 /**
068 * Returns the direct position. This method shall never returns {@code null}, but may returns
069 * {@code this} if invoked on an object which is already a {@code DirectPosition} instance.
070 *
071 * @return The direct position (may be {@code this}).
072 *
073 * @since 2.2
074 */
075 @UML(identifier="direct", obligation=CONDITIONAL, specification=ISO_19107)
076 DirectPosition getDirectPosition();
077 }